Author name code: carpenter ADS astronomy entries on 2022-09-14 author:"Carpenter, Kenneth G." ------------------------------------------------------------------------ Title: Transmissive H2O Reconnaissance Sounder, TH2OR — A Compact Time-Domain Electromagnetic Instrument for Groundwater Detection Authors: Nunes, D. C.; Grimm, R. E.; Barba, N.; Burgin, M.; Carpenter, K.; Krieger, S.; Manthena, R.; McGarey, P. Bibcode: 2022LPICo2655.5054N Altcode: We are developing a planetary low-power, low-mass transient electromagnetic sounding instrument intended to test the hypothesis of an extant deep global aquifer at Mars. Title: VizieR Online Data Catalog: ASTRAL: abundance analysis of HR 465 (Nielsen+, 2020) Authors: Nielsen, K. E.; Carpenter, K. G.; Kober, G. V.; Wahlgren, G. M. Bibcode: 2021yCat..18990166N Altcode: The ASTRAL: Hot Stars Treasury Program was designed to achieve the ultimate combination of high spectral resolution and signal-to-noise over the far- and near-ultraviolet spectrum. The spectrum of HR465 covers the wavelength interval between 1150 and 3047Å and is composed of 21 coadded and merged individual recordings. The spectral resolution shortward of 2334Å is R~30000; however, for wavelengths below 1600Å the spectrum is modeled with a lower value (R~25000) to achieve a better match to the observation. For wavelengths above 2350Å the spectral resolution is ~117000.

(2 data files). Title: After All, Where is the Martian Ground Water? TH2OR Can Help Authors: Nunes, D. C.; Grimm, R. E.; Barba, N.; Burgin, M.; Carpenter, K.; Krieger, S.; Manthena, R.; McGarey, P. Bibcode: 2021LPICo2595.8020N Altcode: The detection of groundwater at Mars continues to be elusive. Geoelectric analogs offer guidance on using of the transient electromagnetic method (TEM), implemented as the TH2OR instrument, to sound for deep groundwater at Mars. Title: Exposing the Lyman-alpha Profiles of Low-Mass Stars Authors: Peacock, Sarah; Barman, Travis Stuart; Carpenter, Kenneth G.; Hintz, Dominik; Loyd, R. O. Parke; Schneider, Adam; Shkolnik, Evgenya L. Bibcode: 2021hst..prop16646P Altcode: Characterizing potentially habitable planets around low mass stars is a key focus of current and upcoming missions such as JWST and TESS. This focus stresses the need for a comprehensive understanding of the radiation environments in which such planets reside. Low-mass stars are typically much more active than solar type stars and the proximity of their habitable zones can be one tenth the distance. The far-ultraviolet (FUV) radiation emitted by these stars has the potential to alter an orbiting planet's atmospheric photochemistry, while the extreme-ultraviolet (EUV) radiation can cause the loss of planetary atmospheres and surface volatiles. Ly-a emission at 1216 A is the dominant radiation source for low mass stars at FUV wavelengths and is critical for informing stellar atmosphere models used to predict the EUV spectrum, but directly measuring a low-mass star's Ly-a emission is almost always impossible because of the contaminating effects of interstellar hydrogen. Using Gaia DR2, we have identified a unique sample of six low mass stars for which a complete and accurate measurement of their Ly-a line profile is possible due to their very large radial velocities. Stars with very large radial velocities (>100 km/s) will have their Ly-a emission Doppler shifted away from contaminating sources allowing for the rare opportunity to measure intrinsic Ly-a emission. These proposed observations of this rare sample of stars will triple the number of stars with Ly-a emission measured in this way and will improve the accuracy of computed spectra for all low-mass stars across wavelengths that drive planetary atmospheric evolution. Title: A New Look into K-giants' Chromospheres Authors: Rau, Gioia; Peacock, Sarah; Carpenter, Kenneth G. Bibcode: 2021RNAAS...5...73R Altcode: We report the preliminary modeling of archival Center for High Angular Resolution Astronomy (CHARA)/Visible spEctroGraph and polArimeter interferometric data of a K-giant star using the PHOENIX atmosphere code. We find that our preparatory model that includes only the chromospheric contribution closely reproduces the observed infrared Ca II triplet line profiles of a test star: the K-giant, β Cet. This preliminary work requires the additional modeling of the wind contribution to improve the agreement with observations. We plan to perform a systematic study of K-giants chromospheric emission with multi-wavelength and multi-technique observations and modeling. Our plans include extending the modeling work to include the underlying wind component for a larger set of stars. Stellar Parameters and Images with a Cophased Array, the second-generation instrument at CHARA, will be the ideal instrument to perform such observations and reveal the chromospheric activity of K-giants. Title: Adaptable Autonomous Ocean Access Through Erupting Conduits Authors: Carpenter, K.; Cable, M. L.; Ono, M.; Kornfeld, R. P. Bibcode: 2020AGUFMP044.0015C Altcode: The EELS architecture is designed to carry the latest instruments. It is adaptable to traverse ocean world inspired terrain, fluidized media, enclosed labyrinthian environments and liquids. It is a snake-like self-propelled endoscope form comprising serially-replicated segments with encapsulated locomotion and bending. Multiple segments sequentially reverse rotations to reduce torsion, or replicate rotations to perform holonomic movements for steering. This is a first of its kind Archimedes screw propulsion configuration that act as wheels, tracks, gripping mechanisms, and propelling units under water working as propellers. These enable a robot to get to a plume and follow the streamline to its source and proceed into the open water. In the case of the unconsolidated plume ejected the robot is buoyant and propelled though the loose media by the threads, even up steep slopes and can burrow. In an open fracture system, EELS extends across the gap near the initiation point of a fracture out of the stream line and pushes the two end screw mechanisms on each side into the walls, driving into the plume, then descending. In the vent the threads bite the side walls, reacting the plume jet forces and creating forward movement when rotated. The robot stays on the edge of the vent pushing on the outer walls allowing the vent streamline to pass through the middle. Sensor feedback enables us to perform accurate force/compliance control without perfect knowledge of the geometry of the environment; hence the robot can naturally conform its shape to the size of the vent. This is used to move the drive screws in any direction to maintain a desired outward force on crack and vent walls, make the screw threads grip the surface, direct the robot around bends, and to follow the correct branch of a conduit across wide gaps. This potential concept has never before been realized. We will report on the latest developments of this concept and implications for unique ocean world science. Title: The Advanced Spectral Library (ASTRAL): Abundance Analysis of the Chemically Peculiar Star HR 465 Authors: Nielsen, Krister E.; Carpenter, Kenneth G.; Kober, Gladys V.; Wahlgren, Glenn M. Bibcode: 2020ApJ...899..166N Altcode: This paper presents the results of the spectrum analysis of the B-type magnetic chemically peculiar star HR 465. HR 465 shows unusual abundance patterns that vary with a period of 21.5 yr. Our observations are recorded at φ = 0.45, 0.68, and 0.85 of the spectroscopic period, where φ = 0 represents the phase of maximum flux in the photometric y-band. Synthetic spectra, computed using an LTE atmosphere model, are fit to high-resolution ultraviolet Hubble Space Telescope (φ = 0.45) spectra obtained as part of the Advanced Spectral Library Project: Hot Stars program. The ultraviolet data are supplemented by high-resolution optical spectra (φ = 0.68 and 0.85) recorded at the Nordic Optical Telescope with the SOFIN spectrograph. The optical data are used as a complement to the high line-density ultraviolet spectrum to derive accurate abundances for elements without spectral lines in the ultraviolet and to improve the abundance phase coverage for many atoms/ions. This analysis presents abundance results for more than 70 atoms/ions and confirms parts of the abundance characteristics previously reported where elements with high mass numbers show significant abundance enhancements compared with solar values while some of the lighter elements show abundance deficiencies. In addition, our measured abundances are consistent with the periodic variability for chromium and rare-earth elements. Our results are compared with earlier investigations of this peculiar object to constrain stellar abundance and diffusion. * Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Title: The Search for Liquid Water and Modern-Day Habitats in the Martian Subsurface Authors: Stamenkovic, V.; Grimm, R. E.; Burgin, M. S.; Barba, N.; Manthena, R.; Carpenter, K.; Wright, D.; Krieger, S.; Arumugam, D.; Beauchamp, R.; Wilcox, B.; Edwards, C. Bibcode: 2020LPI....51.1778S Altcode: We show how transient electromagnetic sounding can be used to search for liquid groundwater and modern-day habitats in the martian subsurface. Title: Stellar Imager (SI) — A UV/Optical Interferometer to Observe the Universe in High Definition Authors: Carpenter, K. G.; Karovska, M.; Rau, G.; Schrijver, C.; SI Team Bibcode: 2020AAS...23530102C Altcode: The concept for a space based, UV/Optical Interferometer with over 200x HST's resolution, named "Stellar Imager" (http://hires.gsfc.nasa.gov/si/), was developed as part of the NASA Vision Mission studies ("NASA Space Science Vision Missions" 2008, ed. M. Allen). SI was a "Landmark/Discovery Mission" in the 2005 Heliophysics Roadmap and a candidate UV-optical interferometer (UVOI) in the 2006 Astrophysics Strategic Plan. SI would enable 0.1 milli-arcsec spectral imaging of stellar surfaces, and many sources in the Universe in general, and open an enormous new "discovery space" for Astrophysics with its combination of high angular resolution, dynamic imaging, and spectral energy resolution. SI's goal is to study the role of magnetism in the Universe and revolutionize our understanding of: 1) Solar/Stellar Magnetic Activity and their impact on Space Weather, Planetary Climates, and Life; 2) Magnetic and Accretion Processes and their roles in the Origin and Evolution of Structure and in the Transport of Matter throughout the Universe; 3) the close-in structure of Active Galactic Nuclei; and 4) Exo-Solar Planet Transits and Disks. Significant technology development is critical to enabling SI and other future space-based, sparse aperture telescopes and distributed-spacecraft missions. The key technology needs include: 1) precision formation flying of many spacecraft, 2) precision metrology over km-scales, 3) closed-loop control of many-element, sparse optical arrays, 4) staged-control systems with very high dynamic ranges (nm to km-scale). We describe the needed technology development, science goals, and feasibility of interferometry from space, as well as provide detail performance parameters and simulations of the data that could be acquired by this space interferometer. Title: Sailing the winds: exploring the mechanisms driving the winds in carbon-rich AGB Stars Authors: Rau, G.; Ohnaka, K.; Wittkowski, M.; Carpenter, K.; Airapetian, V. Bibcode: 2020AAS...23530101R Altcode: Evolved stars produce molecules and dust in their extended atmospheres, enriching significantly the interstellar medium. To understand their mass loss, it is of fundamental importance to investigate the structure and atmospheric dynamics of these stars. V Oph, a carbon-rich Asymptotic Giant Branch (AGB) star, shows extended molecular layers, which vary over a time scales of tens of days. Our study aims at understanding if these variations can be explained by dust-driven winds triggered by stellar pulsation alone, or if other mechanisms are operating. We show our results, presented in a recent ApJ article, using our multi-technique modeling of existing photometric and interferometric VLTI/MIDI data using the latest generation DARWIN models for C-rich AGB stars. Our results include estimates of the values of fundamental stellar parameters and a comparison with evolutionary tracks. We also compute an alternative scenario for the mechanism that drive winds, based on Alfvén waves propagating in V Oph atmosphere. We found that the latter mechanism could partially contribute to the acceleration of the stellar winds of this star. Moreover, using period-luminosity sequences and interferometric modeling, we infer that V Oph could be reclassified to a semi-regular star. Future studies, such as observations with the new capabilities of the James Webb Space Telescope and with the second-generation instrument at the VLTI, MATISSE, will be discussed. Title: AGB star atmospheres modeling as feedback to stellar evolutionary and galaxy models Authors: Rau, Gioia; Wittkowski, M.; Chiavassa, A.; Carpenter, K.; Nielsen, K.; Airapetian, V. S. Bibcode: 2019IAUS..343..491R Altcode: The chemical enrichment of the Universe is considerably affected by the contribution of cool evolved stars. We studied the O-rich star R Peg and the C-rich star V Oph, using respectively the VLTI/GRAVITY and VLTI/MIDI instruments. We interpret the data using grids of 1-D and 3-D dynamic model atmospheres. Title: The Impact of Dust/Gas Ratios on Chromospheric Activity in Red Giant and Supergiant Stars Authors: Carpenter, Kenneth G.; Rau, Gioia Bibcode: 2019IAUS..343..365C Altcode: Stencel et al. (1986) analyzed IUE spectra of a modest set of cool stars and found that they continue to produce chromospheres even in the presence of high dust levels in their outer atmospheres. This reversed the previous results of Jennings (1973) and Jennings & Dyck (1972). We describe an on-going extension of these studies to a sample of stars representing a broader range in dust/gas ratios, using archival IUE and archival and new HST data on both RGB and AGB stars. Surface fluxes in emission lines will be analyzed to assess the chromospheric activity and obscuration by dust in each star, as those fluxes will follow a different pattern for reduced activity (temperature/density dependent) vs. dust obscuration (wavelength dependent). Wind characteristics will be measured by modeling of wind-reversed chromospheric emission lines. Title: Searching for Liquid Water in the Martian Deep with TH2OR Authors: Burgin, M. S.; Stamenkovic, V.; Grimm, R. E.; Arumugam, D.; Beauchamp, R.; Barba, N.; Manthena, R.; Wright, D.; Wilcox, B. H.; Carpenter, K.; Edwards, C. D. Bibcode: 2019AGUFM.P44B..02B Altcode: The "holy grail" of planet exploration is the quest for life. This quest has been framed around "follow the (liquid) water", with the implication that seeking liquid water is tantamount to seeking habitable environments. For Mars, pure liquid water is generally only stable in the deep subsurface, at depths of kilometers. Here, we will describe (i) how we can use transient electromagnetic techniques (TEM) to sense liquid groundwater in the Martian subsurface and (ii) discuss the capabilities of the TH2 OR (Transient H2 O Reconnaissance) TEM instrument, which is currently being developed at JPL - with a targeted capability to detect liquid groundwater in the Martian subsurface down to depths of several kilometers while keeping payload mass and power small. Our TEM approach is different from radar soundings as it is not sensitive to the dielectric constant but rather to electric conductivity and allows much deeper penetration down to aquifer depths of ~1-10 km due to the lower frequencies that are being used (~Hz-kHz for EM versus ~MHz for radar). EM exploits the fact that only slightly-saline water has an electric conductivity orders-of magnitude greater than dry rock. On Mars, we expect especially highly-saline waters due to the much longer residence time of groundwater than on the geologically and hydrologically much more active Earth. Moreover, as the Martian crust is expected to be much drier than the Earth's crust, we expect much greater contrast ratios in electric conductivity between overburden (crustal part above aquifer) and a putative aquifer on Mars than on the Earth. These "Martian TEM advantages" allow us to sound with TH2 OR down to depths of kilometers in order to infer the depth, thickness, and also salinity of liquid subsurface water. Salinity, especially in combination with information on local geothermal gradients, can hence also allow us to indirectly estimate its chemical composition. The ability to characterize the water chemistry to some degree is a particularly important feature of TEM sounding, which other methods generally lack. This opens the possibility to use TH2 OR to detect and characterize the habitability of deep subsurface environments on modern-day Mars. Title: Exobiology Extant Life Surveyor (EELS) Authors: Ono, M.; Carpenter, K.; Cable, M. L.; Wilcox, B. H.; Tosi, L. P. Bibcode: 2019AGUFM.P21D3410O Altcode: Exploring the depths of the Enceladus plume vents for liquid water, searching for life is one of the larger goals of current space exploration. Descending crevasses in ice sheets on Earth to discover the fate of melt water runoff and its effects are of Earth science interest. Finding a path to liquid water is the goal of any mission seeking extant life. We present a potential solution that is adaptable to the envelope of environmental parameters modeled.

The EELS architecture is designed to carry the latest instruments. It is adaptable to traverse ocean world inspired terrain, fluidized media, enclosed labyrinthian environments and liquids. It is a snake-like self-propelled endoscope form comprising serially-replicated segments with encapsulated locomotion and bending. Multiple segments sequentially reverse rotations to reduce torsion in the endoscope, or replicate rotations to perform holonomic movements for steering. The concept is a first of its kind Archimedes screw propulsion configuration that act as wheels, tracks, gripping mechanisms, and propelling units under water working as propellers. These enable a robot to get to a plume and follow the streamline to its source and proceed into the open water. In the case of the unconsolidated plume ejected the robot is buoyant and propelled though the loose media by the threads, even up steep slopes and can burrow. In an open fracture system, EELS extends across the gap near the initiation point of a fracture out of the stream line and pushes the two end screw mechanisms on each side into the walls, driving into the plume, then descending. In the vent the threads bite into the side walls, reacting the plume jet forces and creating forward movement when rotated. The robot stays on the outside of the vent pushing on the outer walls allowing the vent streamline to pass through the middle. The rotation of the screws is reacted by counter rotating secondary units which provide anchoring and thrust. In the case of wide caverns or slip of the leading screw unit, the additional Archimedes screw units provide grip until the leading units find their next secure position. Series elastic actuators enable us to perform accurate force/compliance control without perfect knowledge of the geometry of the environment; hence the robot can naturally conform its shape to the size of the vent. This is used to move the drive screws in any direction to maintain a desired outward force on crack and vent walls, make the screw threads grip the surface, direct the robot around bends, and to follow the correct branch of a conduit across wide gaps. This architecture has never been realized in any other robots to this point. It prioritizes reducing traversal time to the water gas interface in case of a primary battery only mission. Sensor arrays, cameras, and instruments at the head segment will provide in-situ feedback. Title: Feasibility of a Mission to Enceladus' Subsurface Ocean for the Next Planetary Science Decadal Survey Authors: Hofgartner, J. D.; Choukroun, M.; Cable, M. L.; Brophy, J. R.; Carpenter, K.; Polit Casillas, R.; Chmielewski, A. B.; Cooley, P.; Cutts, J. A.; Fleurial, J. P.; Landau, D.; Parness, A.; Reh, K. R.; Wilcox, B. H. Bibcode: 2019AGUFM.P34C..06H Altcode: Saturn's moon Enceladus is a high priority target for astrobiology as it harbors a subsurface ocean that erupts into space and is likely habitable. Searching for life at Enceladus is a top priority, near term goal of Ocean Worlds exploration (e.g., Hendrix et al., 2019, The NASA Roadmap to Ocean Worlds, and references therein). Several mission concepts to search for life in Enceladus' plume have been studied including proposed Discovery and New Frontiers missions. Is a mission that accesses the ocean and directly searches for life in unaltered ocean samples feasible in the coming decade? We present the results of an internal study at the Jet Propulsion Laboratory for an ambitious yet implementable mission concept to Enceladus' ocean. This innovative mission would include autonomous landing at Enceladus' south pole and penetration through the ice shell via both an intelligent melt probe and an adaptable multi-terrain robot (robotic eel) that navigates down an erupting vent. Both the eel and melt probe would be instrumented, able to search for evidence of life in samples acquired during their descent, and capable of maneuvering within the ocean. The baseline mission architecture would include a solar-powered orbiter to identify safe, compelling landing zones and relay data to Earth as well as an RTG-powered lander that would execute a precision landing, deploy the melt and eel probes, relay data to the orbiter, and also search for evidence of life in samples of surface material. A new surface sampling system has been developed to enable the latter search, based on experimentally-derived surface strength expectations (Hodyss et al., this meeting). The mission design would not be inhibited by winter darkness at Enceladus' south pole; all operations could be accomplished at any Enceladus season. The concept would utilize the state-of-the-art in astrodynamics techniques, systems architecture, optimization, and advanced manufacturing. A single Flagship-level mission that would search for life on Enceladus' surface, within its ice shell, and in the subsurface ocean may be the most comprehensive opportunity for astrobiology in the coming decade. Title: Mobile Instruments for Mars Exploration (MIMEs) (Characterizing Recurring Slope Linea) Authors: Carpenter, K.; Noell, A. C.; Christensen, L. E.; Zent, A.; Quinn, R. C. Bibcode: 2019AGUFM.P44B..07C Altcode: Definitive confirmation of current liquid water activity on Mars would be a major step in establishing the present day habitability of Mars and the possibility of extant life. The recurring slope lineae (RSL) are one of the most intriguing targets for exploring current water activity.

The RSL are identified as seasonally dependent streaks that darken and grow downward on steep (≥20°) slopes. Currently, they are best explained as intergranular briny water flows percolating through the top layers of the regolith, but orbital observations cannot provide a definitive confirmation. However, landing and probing near RSL presents a number of challenges to traditional mission architectures including stringent planetary protection requirements of a Mars special region mission.

To this we propose utilizing two versions of the Pop-Up Flat Folding Explorer Rover capable of traversing greater than 50 degree slopes and able to be cleaned to a greater then log 7 reduction in bio burden. These will be equipped with the Thermal and Electrical Conductivity Probe (TECP) and/or a miniature version of the Tunable Laser Spectrometer (TLS) to characterize RSL and establish habitability. Having multiple PUFFER agents increases the communication range of the field survey by using individual PUFFERs as repeaters.

We will determine the permafrost freeze-thaw cycle that drives the underlying RSL processes at our field sites and characterize the chemical makeup of the flows. This will inform on the period of liquid phase and the available chemicals for biological processes. Overall, the MIME mission concept addresses fundamental NASA priorities of searching for life and habitable areas in our solar system. On Mars, present day habitability is still fundamentally tied to finding liquid water.

The Curiosity rover has provided abundant evidence of Mars habitability 3 - 4 billion years ago in the active lacustrine system of Gale Crater. MIME will pursue evidence for modern day liquid flows, and hence modern day habitability. A confirmed detection of liquid activity near the surface of Mars would intensify the already robust debate about the suitability of exploring Mars not only for signatures of past life, but also for signatures of extant life. Title: Mars Subsurface Hydrology in 4D and Implications for Extant Life Authors: Stamenkovic, V.; Plesa, A. C.; Breuer, D.; Burgin, M.; Grimm, R.; Arumugam, D.; Beauchamp, R.; Barba, N.; Manthena, R.; Wright, D.; Wilcox, B.; Carpenter, K.; Edwards, C. Bibcode: 2019LPICo2108.5052S Altcode: In this study, we show how ground-water levels might have evolved over the last 4.5 Ga inside the martian subsurface as a function of location, depth, and time using numerical geodynamical evolution models. We also show how to search for them. Title: VizieR Online Data Catalog: ASTRAL: reference spectra for evolved M stars (Carpenter+, 2018) Authors: Carpenter, K. G.; Nielsen, K. E.; Kober, G. V.; Ayres, T. R.; Wahlgren, G. M.; Rau, G. Bibcode: 2019yCat..18690157C Altcode: This paper focuses on the evolved cool stars γCru and αOri and compares their spectral characteristics to the well-studied K1.5III star αBoo (Hinkle+ 2005uaas.book.....H). The observational strategy for α Ori and γ Cru, as for the other objects in the ASTRAL Cool Star Program, was crafted to find the optimal combination of spectral resolution and signal-to-noise over the complete FUV and NUV spectra (1150-3159Å).

All of the HST Space Telescope Imaging Spectrograph (STIS) spectra for the two objects are splined in a top-level data set covering the entire wavelength region. An overview of the data used in this paper is presented in Table 1, and a more detailed description of the data, including the observing strategy, data reduction, coaddition, and splicing, can be found on the Advances Spectral Library (ASTRAL) website (http://casa.colorado.edu/~ayres/ASTRAL/) and at the Mikulski Archive for Space Telescopes (MAST) (http://archive.stsci.edu/prepds/astral/).

(4 data files). Title: The Potential of Exozodiacal Disks Observations with the WFIRST Coronagraph Instrument Authors: Mennesson, B.; Bailey, V.; Kasdin, J.; Trauger, J.; Absil, O.; Akeson, R.; Armus, L.; Baudino, J. L.; Baudoz, P.; Bellini, A.; Bennett, D.; Berriman, B.; Boccaletti, A.; Calchi-Novati, S.; Carpenter, K.; Chen, C.; Danchi, W.; Debes, J.; Defrere, D.; Ertel, S.; Frerking, M.; Gelino, C.; Girard, J.; Groff, T.; Kane, S.; Helou, G.; Kalirai, J.; Kral, Q.; Krist, J.; Kruk, J.; Hasegawa, Y.; Lagrange, A. M.; Laine, S.; Langlois, M.; Lowrance, P.; Maire, A. L.; Malhotra, S.; Mandell, A.; Marshall, P.; McElwain, M.; Meshkat, T.; Millan-Gabet, R.; Moustakas, L.; Nemati, B.; Paladini, R.; Postman, M.; Pueyo, L.; Quintana, E.; Ramirez, S.; Rhodes, J.; Riggs, A. J. E.; Rizzo, M.; Rouan, D.; Soummer, R.; Stapelfeldt, K.; Stark, C.; Turnbull, M.; van der Marel, R.; Vigan, A.; Ygouf, M.; Wyatt, M.; Zhao, F.; Zimmerman, N. Bibcode: 2019arXiv190902161M Altcode: The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) will be the first high-performance stellar coronagraph using active wavefront control for deep starlight suppression in space, providing unprecedented levels of contrast, spatial resolution, and sensitivity for astronomical observations in the optical. One science case enabled by the CGI will be taking images and(R~50)spectra of faint interplanetary dust structures present in the habitable zone of nearby sunlike stars (~10 pc) and within the snow-line of more distant ones(~20pc), down to dust density levels commensurate with that of the solar system zodiacal cloud. Reaching contrast levels below~10-7 for the first time, CGI will cross an important threshold in debris disks physics, accessing disks with low enough optical depths that their structure is dominated by transport phenomena than collisions. Hence, CGI results will be crucial for determining how exozodiacal dust grains are produced and transported in low-density disks around mature stars. Additionally, CGI will be able to measure the brightness level and constrain the degree of asymmetry of exozodiacal clouds around individual nearby sunlike stars in the optical, at the ~10x solar zodiacal emission level. This information will be extremely valuable for optimizing the observational strategy of possible future exo-Earth direct imaging missions, especially those planning to operate at optical wavelengths, such as Habitable Exoplanet Observatory (HabEx) and the Large Ultraviolet/Optical/Infrared Surveyor (LUVOIR). Title: Constraining Stellar Parameters and Atmospheric Dynamics of the Carbon AGB star V Oph Authors: Rau, Gioia; Ohnaka, Keiichi; Wittkowski, Markus; Airapetian, Vladimir; Carpenter, Kenneth G. Bibcode: 2019ApJ...882...37R Altcode: 2019arXiv190708693R Molecules and dust produced by the atmospheres of cool evolved stars contribute to a significant amount of the total material found in the interstellar medium. To understand the mechanism behind the mass loss of these stars, it is of pivotal importance to investigate the structure and dynamics of their atmospheres. Our goal is to verify if the extended molecular and dust layers of the carbon-rich asymptotic giant branch (AGB) star V Oph, and their time variations, can be explained by dust-driven winds triggered by stellar pulsation alone, or if other mechanisms are in play. We model V Oph mid-infrared interferometric VLTI-MIDI data (8-13 μm), at phases 0.18, 0.49, and 0.65, together with literature photometric data, using the latest-generation self-consistent dynamic atmosphere models for carbon-rich stars: DARWIN. We determine the fundamental stellar parameters: T eff = 2600 K, L bol = 3585 L ⊙, M = 1.5 M ⊙, C/O = 1.35, \dot{M}=2.50× {10}-6 M ⊙ yr-1. We calculate the stellar photospheric radii at the three phases: 479, 494, 448 R ⊙ and the dust radii: 780, 853, 787 R ⊙. The dynamic models can fairly explain the observed N-band visibility and spectra, although there is some discrepancy between the data and the models, which is discussed in the text. We discuss the possible causes of the temporal variations of the outer atmosphere, deriving an estimate of the magnetic field strength, and computing upper limits for the Alfvén waves velocity. In addition, using period-luminosity sequences, and interferometric modeling, we suggest V Oph as a candidate to be reclassified as a semi-regular star. Title: Stars at High Spatial Resolution Authors: Carpenter, Kenneth G.; van Belle, Gerard; Brown, Alexander; Cranmer, Steven R.; Drake, Jeremy; Dupree, Andrea K.; Creech-Eakman, Michelle; Evans, Nancy R.; Grady, Carol A.; Guinan, Edward F.; Harper, Graham; Karovska, Margarita; Kolenberg, Katrien; Labeyrie, Antoine; Linsky, Jeffrey; Peters, Geraldine J.; Rau, Gioia; Ridgway, Stephen; Roettenbacher, Rachael M.; Saar, Steven H.; Walter, Frederick M.; Wood, Brian Bibcode: 2019arXiv190805665C Altcode: We summarize some of the compelling new scientific opportunities for understanding stars and stellar systems that can be enabled by sub-milliarcsec (sub-mas) angular resolution, UV-Optical spectral imaging observations, which can reveal the details of the many dynamic processes (e.g., evolving magnetic fields, accretion, convection, shocks, pulsations, winds, and jets) that affect stellar formation, structure, and evolution. These observations can only be provided by long-baseline interferometers or sparse aperture telescopes in space, since the aperture diameters required are in excess of 500 m (a regime in which monolithic or segmented designs are not and will not be feasible) and since they require observations at wavelengths (UV) not accessible from the ground. Such observational capabilities would enable tremendous gains in our understanding of the individual stars and stellar systems that are the building blocks of our Universe and which serve as the hosts for life throughout the Cosmos. Title: Understanding Component/Materials Performance in the Lunar Environment Authors: Patterson, M. C. L.; Tucker, J.; Carpenter, K.; Parness, A. Bibcode: 2019LPICo2152.5056P Altcode: A test environment that closely approximates the lunar surface has been established to characterize the wear and degradation mechanisms associated with components such as gear boxes, predict performance, and establish mitigation strategies. Title: Cool, evolved stars: results, challenges, and promises for the next decade Authors: Rau, Gioia; Montez, Rodolfo, Jr.; Carpenter, Kenneth; Wittkowski, Markus; Bladh, Sara; Karovska, Margarita; Airapetian, Vladimir; Ayres, Tom; Boyer, Martha; Chiavassa, Andrea; Clayton, Geoffrey; Danchi, William; De Marco, Orsola; Dupree, Andrea K.; Kaminski, Tomasz; Kastner, Joel H.; Kerschbaum, Franz; Linsky, Jeffrey; Lopez, Bruno; Monnier, John; Montargès, Miguel; Nielsen, Krister; Ohnaka, Keiichi; Ramstedt, Sofia; Roettenbacher, Rachael; ten Brummelaar, Theo; Paladini, Claudia; Sarangi, Arkaprabha; van Belle, Gerard; Ventura, Paolo Bibcode: 2019BAAS...51c.241R Altcode: 2019arXiv190304585R; 2019astro2020T.241R This White Paper identifies compelling scientific opportunities in the field of Cool, Evolved Stars, describing the observational and theoretical challenges to our understanding, and the key advancements made. We portray the pathway towards understanding, and identify, through recommendations, which advancements are necessary in 2020-2030 & beyond. Title: Stars at High Spatial Resolution Authors: Carpenter, Kenneth; van Belle, Gerard; Brown, Alexander; Cranmer, Steven R.; Drake, Jeremy; Dupree, Andrea K.; Creech-Eakman, Michelle; Evans, Nancy R.; Grady, Carol A.; Guinan, Edward F.; Harper, Graham; Karovska, Margarita; Kolenberg, Katrien; Labeyrie, Antoine; Linsky, Jeffrey; Peters, Geraldine J.; Rau, Gioia; Ridgway, Stephen; Roettenbacher, Rachael M.; Saar, Steven H.; Walter, Frederick M.; Wood, Brian Bibcode: 2019BAAS...51c..56C Altcode: 2019astro2020T..56C We summarize compelling new scientific opportunities for understanding stars and stellar systems that can be enabled by sub-milliarcsec angular resolution, UV/Optical spectral imaging observations. These can reveal details of many dynamic processes that affect stellar formation, structure, and evolution. Title: High Angular Resolution Astrophysics: Resolving Stellar Surface Features Authors: Roettenbacher, Rachael; Norris, Ryan; Baron, Fabien; Carpenter, Kenneth; Creech-Eakman, Michelle; Gies, Douglas; Maccarone, Thomas; Monnier, John; Rau, Gioia; Ridgway, Stephen; Schaefer, Gail; ten Brummelaar, Theo Bibcode: 2019BAAS...51c.181R Altcode: 2019arXiv190304660R; 2019astro2020T.181R We discuss the main types of stars for which imaging surface features is currently possible using long-baseline optical interferometry and what improved observing techniques would provide for imaging stellar surface features. Title: Characterizing Component Performance in the Lunar Environment Authors: Patterson, M. C. L.; Tucker, J.; Carpenter, K.; Parness, A. Bibcode: 2019LPI....50.2756P Altcode: Understanding how systems perform on planetary surfaces is critical to mission success. Simulated lunar environments allow accurate component life predictions. Title: The Wide Field Infrared Survey Telescope: 100 Hubbles for the 2020s Authors: Akeson, Rachel; Armus, Lee; Bachelet, Etienne; Bailey, Vanessa; Bartusek, Lisa; Bellini, Andrea; Benford, Dominic; Bennett, David; Bhattacharya, Aparna; Bohlin, Ralph; Boyer, Martha; Bozza, Valerio; Bryden, Geoffrey; Calchi Novati, Sebastiano; Carpenter, Kenneth; Casertano, Stefano; Choi, Ami; Content, David; Dayal, Pratika; Dressler, Alan; Doré, Olivier; Fall, S. Michael; Fan, Xiaohui; Fang, Xiao; Filippenko, Alexei; Finkelstein, Steven; Foley, Ryan; Furlanetto, Steven; Kalirai, Jason; Gaudi, B. Scott; Gilbert, Karoline; Girard, Julien; Grady, Kevin; Greene, Jenny; Guhathakurta, Puragra; Heinrich, Chen; Hemmati, Shoubaneh; Hendel, David; Henderson, Calen; Henning, Thomas; Hirata, Christopher; Ho, Shirley; Huff, Eric; Hutter, Anne; Jansen, Rolf; Jha, Saurabh; Johnson, Samson; Jones, David; Kasdin, Jeremy; Kelly, Patrick; Kirshner, Robert; Koekemoer, Anton; Kruk, Jeffrey; Lewis, Nikole; Macintosh, Bruce; Madau, Piero; Malhotra, Sangeeta; Mandel, Kaisey; Massara, Elena; Masters, Daniel; McEnery, Julie; McQuinn, Kristen; Melchior, Peter; Melton, Mark; Mennesson, Bertrand; Peeples, Molly; Penny, Matthew; Perlmutter, Saul; Pisani, Alice; Plazas, Andrés; Poleski, Radek; Postman, Marc; Ranc, Clément; Rauscher, Bernard; Rest, Armin; Roberge, Aki; Robertson, Brant; Rodney, Steven; Rhoads, James; Rhodes, Jason; Ryan, Russell, Jr.; Sahu, Kailash; Sand, David; Scolnic, Dan; Seth, Anil; Shvartzvald, Yossi; Siellez, Karelle; Smith, Arfon; Spergel, David; Stassun, Keivan; Street, Rachel; Strolger, Louis-Gregory; Szalay, Alexander; Trauger, John; Troxel, M. A.; Turnbull, Margaret; van der Marel, Roeland; von der Linden, Anja; Wang, Yun; Weinberg, David; Williams, Benjamin; Windhorst, Rogier; Wollack, Edward; Wu, Hao-Yi; Yee, Jennifer; Zimmerman, Neil Bibcode: 2019arXiv190205569A Altcode: The Wide Field Infrared Survey Telescope (WFIRST) is a 2.4m space telescope with a 0.281 deg^2 field of view for near-IR imaging and slitless spectroscopy and a coronagraph designed for > 10^8 starlight suppresion. As background information for Astro2020 white papers, this article summarizes the current design and anticipated performance of WFIRST. While WFIRST does not have the UV imaging/spectroscopic capabilities of the Hubble Space Telescope, for wide field near-IR surveys WFIRST is hundreds of times more efficient. Some of the most ambitious multi-cycle HST Treasury programs could be executed as routine General Observer (GO) programs on WFIRST. The large area and time-domain surveys planned for the cosmology and exoplanet microlensing programs will produce extraordinarily rich data sets that enable an enormous range of Archival Research (AR) investigations. Requirements for the coronagraph are defined based on its status as a technology demonstration, but its expected performance will enable unprecedented observations of nearby giant exoplanets and circumstellar disks. WFIRST is currently in the Preliminary Design and Technology Completion phase (Phase B), on schedule for launch in 2025, with several of its critical components already in production. Title: M-Giant Mass-Loss Rates and Wind Parameters from UV Emission Line Profiles Authors: Carpenter, Kenneth G.; Rau, Gioia; Nielsen, Krister E. Bibcode: 2019AAS...23336506C Altcode: Strong chromospheric emission lines in the UV spectra of M giants show superposed absorption features created by their photon-scattering winds. These self-reversed emission profiles provide us with an opportunity to assess important parameters of the wind, including flow and turbulent velocities, the optical depth of the wind above the region of photon creation, and the star's mass-loss rate. We use the Sobolev with Exact Integration (SEI) radiative transfer code, along with simple models of the outer atmospheric structure and wind, to determine the wind characteristics of the two M-giant stars Gamma Cru (M3.4) and Mu Gem (M3IIIab). We use this code because it is computationally fast and allows a great number of possible wind models to be examined. The program calculates line profiles for the Mg II (UV1) lines and a range of unblended Fe II lines. These lines represent a wide range of wind opacities, and thus different heights in the atmosphere. The assumed wind properties are iterated, until the predicted profiles match the observations (in this case HST/GHRS UV spectra), over as many lines as possible. We present estimates of the wind parameters for these two M-giant stars, and offer a comparison to wind properties previously-determined for low-gravity K stars using the same technique and similar data. Title: Key Technologies for the Wide Field Infrared Survey Telescope Coronagraph Instrument Authors: Bailey, Vanessa P.; Armus, Lee; Balasubramanian, Bala; Baudoz, Pierre; Bellini, Andrea; Benford, Dominic; Berriman, Bruce; Bhattacharya, Aparna; Boccaletti, Anthony; Cady, Eric; Calchi Novati, Sebastiano; Carpenter, Kenneth; Ciardi, David; Crill, Brendan; Danchi, William; Debes, John; Demers, Richard; Dohlen, Kjetil; Effinger, Robert; Ferrari, Marc; Frerking, Margaret; Gelino, Dawn; Girard, Julien; Grady, Kevin; Groff, Tyler; Harding, Leon; Helou, George; Henning, Avenhaus; Janson, Markus; Kalirai, Jason; Kane, Stephen; Kasdin, N. Jeremy; Kenworthy, Matthew; Kern, Brian; Krist, John; Kruk, Jeffrey; Lagrange, Anne Marie; Laine, Seppo; Langlois, Maud; Le Coroller, Herve; Lindensmith, Chris; Lowrance, Patrick; Maire, Anne-Lise; Malhotra, Sangeeta; Mandell, Avi; McElwain, Michael; Mejia Prada, Camilo; Mennesson, Bertrand; Meshkat, Tiffany; Moody, Dwight; Morrissey, Patrick; Moustakas, Leonidas; N'Diaye, Mamadou; Nemati, Bijan; Noecker, Charley; Paladini, Roberta; Perrin, Marshall; Poberezhskiy, Ilya; Postman, Marc; Pueyo, Laurent; Ramirez, Solange; Ranc, Clement; Rhodes, Jason; Riggs, A. J. E.; Rizzo, Maxime; Roberge, Aki; Rouan, Daniel; Schlieder, Joshua; Seo, Byoung-Joon; Shaklan, Stuart; Shi, Fang; Soummer, Remi; Spergel, David; Stapelfeldt, Karl; Stark, Christopher; Tamura, Motohide; Tang, Hong; Trauger, John; Turnbull, Margaret; van der Marel, Roeland; Vigan, Arthur; Williams, Benjamin; Wollack, Edward J.; Ygouf, Marie; Zhao, Feng; Zhoud, Hanying; Zimmerman, Neil Bibcode: 2019arXiv190104050B Altcode: The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) is a high-contrast imager and integral field spectrograph that will enable the study of exoplanets and circumstellar disks at visible wavelengths. Ground-based high-contrast instrumentation has fundamentally limited performance at small working angles, even under optimistic assumptions for 30m-class telescopes. There is a strong scientific driver for better performance, particularly at visible wavelengths. Future flagship mission concepts aim to image Earth analogues with visible light flux ratios of more than 10^10. CGI is a critical intermediate step toward that goal, with a predicted 10^8-9 flux ratio capability in the visible. CGI achieves this through improvements over current ground and space systems in several areas: (i) Hardware: space-qualified (TRL9) deformable mirrors, detectors, and coronagraphs, (ii) Algorithms: wavefront sensing and control; post-processing of integral field spectrograph, polarimetric, and extended object data, and (iii) Validation of telescope and instrument models at high accuracy and precision. This white paper, submitted to the 2018 NAS Exoplanet Science Strategy call, describes the status of key CGI technologies and presents ways in which performance is likely to evolve as the CGI design matures. Title: HST/GHRS Observations of Cool, Low-gravity Stars. VI. Mass-loss Rates and Wind Parameters for M Giants Authors: Rau, Gioia; Nielsen, Krister E.; Carpenter, Kenneth G.; Airapetian, Vladimir Bibcode: 2018ApJ...869....1R Altcode: 2018arXiv181110679R The photon-scattering winds of M giants absorb parts of the chromospheric emission lines and produce self-reversed spectral features in high-resolution Hubble Space Telescope (HST)/GHRS spectra. These spectra provide an opportunity to assess fundamental parameters of the wind, including flow and turbulent velocities, the optical depth of the wind above the region of photon creation, and the star’s mass-loss rate. This paper is the last paper in the series “GHRS Observations of Cool, Low-Gravity Stars” the last several have compared empirical measurements of spectral emission lines with models of the winds and mass loss of K giants and supergiants. We have used the Sobolev with Exact Integration radiative transfer code, along with simple models of the outer atmosphere and wind, to determine and compare the wind characteristics of the two M-giant stars, γ Cru (M3.5III) and μ Gem (M3IIIab), with previously derived values for low-gravity K-stars. The analysis specifies the wind parameters and calculates line profiles for the Mg II resonance lines, in addition to a range of unblended Fe II lines. Our line sample covers a large range of wind opacities and, therefore, probes a range of heights in the atmosphere. Our results show that μ Gem has a slower and more turbulent wind than γ Cru. Also, μ Gem has a weaker chromosphere, in terms of surface flux, with respect to γ Cru. This suggests that μ Gem is more evolved than γ Cru. Comparing the two M giants in this work with previously studied K-giant and supergiant stars (α Tau, γ Dra, and λ Vel) reveals that the M giants have slower winds than the earlier giants, but exhibit higher mass-loss rates. Our results are interpreted in the context of the winds being driven by Alfvén waves. Title: The Advanced Spectral Library (ASTRAL): Reference Spectra for Evolved M Stars Authors: Carpenter, Kenneth G.; Nielsen, Krister E.; Kober, Gladys V.; Ayres, Thomas R.; Wahlgren, Glenn M.; Rau, Gioia Bibcode: 2018ApJ...869..157C Altcode: 2018arXiv181111865C The HST Treasury Program Advanced Spectral Library Project: Cool Stars was designed to collect representative, high-quality UV spectra of eight evolved F-M type cool stars. The Space Telescope Imaging Spectrograph (STIS) echelle spectra of these objects enable investigations of a broad range of topics, including stellar and interstellar astrophysics. This paper provides a guide to the spectra of the two evolved M stars, the M2 Iab supergiant α Ori and the M3.4 giant γ Cru, with comparisons to the prototypical K1.5 giant α Boo. It includes identifications of the significant atomic and molecular emission and absorption features and discusses the character of the photospheric and chromospheric continua and line spectra. The fluorescent processes responsible for a large portion of the emission-line spectrum, the characteristics of the stellar winds, and the available diagnostics for hot and cool plasmas are also summarized. This analysis will facilitate the future study of the spectra, outer atmospheres, and winds, not only of these objects but of numerous other cool, low-gravity stars, for years to come.

Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Title: Shifting the Paradigm of Coping with Nyx on the Moon — a Ground-Penetrating Radar Case Authors: Nunes, D. C.; Carpenter, K.; Haynes, M.; de la Croix, J. P. Bibcode: 2018LPICo2106.7012N Altcode: A multi-static, autonomous ground-penetrating radar instrument, MARGE, will incorporate strategies to be more tolerant of the lunar diurnal thermal cycle. Title: The Mass of the Cepheid V350 Sgr Authors: Evans, Nancy Remage; Proffitt, Charles; Carpenter, Kenneth G.; Winston, Elaine M.; Kober, Gladys V.; Günther, H. Moritz; Gorynya, Natalia; Rastorguev, Alexey; Inno, L. Bibcode: 2018ApJ...866...30E Altcode: 2018arXiv180810472E V350 Sgr is a classical Cepheid suitable for mass determination. It has a hot companion which is prominent in the ultraviolet (UV) and which is not itself a binary. We have obtained two high-resolution echelle spectra of the companion at orbital velocity maximum and minimum with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope in the 1320 to 1510 Å region. By cross-correlating these spectra we obtained the orbital velocity amplitude of the companion with an uncertainty in the companion amplitude of 1.9 km s-1. This provides a mass ratio of the Cepheid to the companion of 2.1. The UV energy distribution of the companion provides the mass of the companion, yielding a Cepheid mass of 5.2 ± 0.3 M ⊙. This mass requires some combination of moderate main sequence core convective overshoot and rotation to match evolutionary tracks.

Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Title: Imaging the Surfaces of Stars from Space Authors: Carpenter, Kenneth; Rau, Gioia Bibcode: 2018iss..confE...4C Altcode: Imaging of Stellar Surfacess has been dominated to-date by ground-based observations, but space-based facilities offer tremendous potential for extending the wavelength coverage and ultimately the resolution of such efforts. We review the imaging accomplished so far from space and then talk about exciting future prospects. The earliest attempts from space indirectly produced surface maps via the Doppler Imaging Technique, using UV spectra obtained with the International Ultraviolet Explorer (IUE). Later, the first direct UV images were obtained with the Hubble Space Telescope (HST), of Mira and Betelgeuse, using the Faint Object Camera (FOC). We will show this work and then investigate prospects for IR imaging with the James Webb Space Telescope (JWST). The real potential of space-based Imaging of Stellar Surfacess, however, lies in the future, when large-baseline Fizeau interferometers, such as the UV-optical Stellar Imager (SI) Vision Mission, with a 30-element array and 500m max baseline, are flown. We describe SI and its science goals, which include 0.1 milli-arcsec spectral Imaging of Stellar Surfacess and the probing of internal structure and flows via asteroseismology. Title: The WFIRST Exoplanet Microlensing Survey Authors: Bennett, David P.; Akeson, Rachel; Anderson, Jay; Armus, Lee; Bachelet, Etienne; Bailey, Vanessa; Barclay, Thomas; Barry, Richard; Beaulieu, Jean-Phillipe; Belini, Andrea; Benford, Dominic J.; Bhattacharya, Aparna; Boyd, Padi; Bozza, Valerio; Calchi Novati, Sebastiano; Carpenter, Kenneth; Cassan, Arnaud; Ciardi, David; Cole, Andrew; Colon, Knicole; Coutures, Christian; Dominik, Martin; Fouque, Pascal; Grady, Kevin; Groff, Tyler; Henderson, Calen B.; Horne, Keith; Gelino, Christopher; Gelino, Dawn; Kalirai, Jason; Kane, Stephen; Kasdin, N. Jeremy; Kruk, Jeffrey; Laine, Seppo; Lambrechts, Michiel; Mancini, Luigi; Mandell, Avi; Malhotra, Sangeeta; Mao, Shude; McElwain, Michael; Mennesson, Bertrand; Meshkat, Tiffany; Moustakas, Leonidas; Munoz, Jose A.; Nataf, David; Paladini, Roberta; Pascucci, Ilaria; Penny, Matthew; Poleski, Radek; Quintana, Elisa; Ranc, Clement; Rattenbury, Nicholas; Rhodes, James; Rhodes, Jason D.; Rizzo, Maxime; Roberge, Aki; Rogers, Leslie; Sahu, Kailash C.; Schlieder, Joshua; Seager, Sara; Shvartzvald, Yossi; Soummer, Remi; Spergel, David; Stassun, Keivan G.; Street, Rachel; Sumi, Takahiro; Suzuki, Daisuke; Trauger, John; van der Marel, Roeland; Williams, Benjamin F.; Wollack, Edward J.; Yee, Jennifer; Yonehara, Atsunori; Zimmerman, Neil Bibcode: 2018arXiv180308564B Altcode: The Wide Field Infrared Survey Telescope (WFIRST) was the top ranked large space mission in the 2010 New Worlds, New Horizons decadal survey, and it was formed by merging the science programs of 3 different mission concepts, including the Microlensing Planet Finder (MPF) concept (Bennett \etal\ 2010). The WFIRST science program (Spergel \etal\ 2015) consists of a general observer program, a wavefront controlled technology program, and two targeted science programs: a program to study dark energy, and a statistical census of exoplanets with a microlensing survey, which uses nearly one quarter of WFIRST's observing time in the current design reference mission. The New Worlds, New Horizons (decadal survey) midterm assessment summarizes the science case for the WFIRST exoplanet microlensing survey with this statement: "WFIRST's microlensing census of planets beyond 1 AU will perfectly complement Kepler's census of compact systems, and WFIRST will also be able to detect free-floating planets unbound from their parent stars\rlap." Title: Weighing supermassive black holes with the UV photon sieve space telescope Authors: Airapetian, Vladimir; Upton, Robert S.; Davila, Joseph; Marzouk, Marzouk; Carpenter, Kenneth G.; Weaver, Kimberly Bibcode: 2017SPIE10564E..3RA Altcode: The Photon Sieve Space Telescope (PSST) is a space-based ultra high-resolution (5 mas) narrow band (λ/Δλ ≃ 1000) spectral UV imager providing spectral imaging of astronomical objects in Ly - , CIV and NV emission lines. Science obtained with this telescope will revolutionize our understanding of a whole range of astrophysical processes in the local and distant universe. There will be a dramatic increase in the number of observed moderate and large SMBH masses as well as extra-solar protoplanetary disks. The observations will also enable tracing the star formation rates in active galaxies. We present the optical design, the properties and the future implementation of the proposed UV photon sieve space telescope. Title: Detecting the Beacons of Life with Exo-Life Beacon Space Telescope (ELBST) Authors: Airapetian, V. S.; Danchi, W. C.; Chen, P. C.; Rabin, D. M.; Carpenter, K. G.; Mlynczak, M. G. Bibcode: 2017LPICo1989.8214A Altcode: We propose a new observational strategy, the “Exo-Life Beacon Space Telescope,” for detecting the signatures of “beacons” of life defined as high signal and low spectral resolution thermal emission from molecules associated with life signatures. Title: Bridging the Gap between Coronal and Non-Coronal Evolved Stars Authors: Carpenter, Kenneth G.; Nielsen, Krister E.; Kober, Gladys V. Bibcode: 2017AAS...22915102C Altcode: The Hubble Space Telescope (HST) Treasury Program "Advanced Spectral Library (ASTRAL)" enables investigations of a broad range of problems including the character and dynamics of the wind and chromosphere of cool stars. This paper presents an investigation of the change in spectral characteristics when transitioning from the cool non-coronal objects with fluorescent emission spectra from the iron group elements, molecular hydrogen, and carbon monoxide to the warmer stars on the blue side of the Linsky-Haish dividing line in the HR diagram. These warmer objects exhibit chromospheric emission from significantly hotter environments in addition to coronal signatures, while the hybrid stars overlap in the HR-diagram with some of the non-coronal objects and share many spectral characteristics but show differences in the wind properties. We show how the wind, fluorescent features, and hot stellar signatures dramatically change with spectral class by comparing the already analyzed non-coronal objects (Alpha Ori, Gamma Cru) with the hybrid stars (Gamma Dra, Beta Gem and Alpha Aqr) and the coronal object Beta Dra. We aim to gain understanding of the physical processes in these objects' outer atmospheres and their evolutionary tracks. Title: A Precision Measurement of the Mass of the Cepheid V350 Sgr Authors: Evans, Nancy Remage; Bono, Giuseppe; Carpenter, Kenneth G.; Gorynya, Natashya; Inno, Laura; Proffitt, Charles R.; Rastorgouev, Alexey Bibcode: 2016hst..prop14332E Altcode: An important HST UV legacy is the measurement of the masses of Cepheids. HST has provided double-lined spectroscopic binaries since the orbital velocity amplitude of hot companions can be measured on high resolution ultraviolet spectra. STIS UV E140H echelle observations of the Cepheid V350 Sgr will yield a dramatic improvement in the precision of its mass (5% or 0.25 solar masses vs the current 17%). This will allow a unique and critical test of the role of convective overshoot in the evolution of intermediate mass stars, by coupling the measured mass with a luminosity. Furthermore, the very accurate masses (1-2%) recently determined for two Cepheids in eclipsing binaries in the LMC mean the mass--luminosity relation for Cepheids can be compared for two metallicities. This will improve both confidence in the use of Cepheids as primary extragalactic distance indicators and also our understanding of the evolution of intermediate mass stars. Title: PUFFER (Pop-Up Flat Folding Explorer Robots) Authors: Karras, J.; Carpenter, K.; Fuller, C.; Parcheta, C. Bibcode: 2016LPICo1980.4125K Altcode: PUFFER (Pop-Up Flat Folding Explorer Robots) are origami-inspired folding robots with extreme terrain mobility. PUFFERs are low-volume, low-mass, and low-cost robots for high-reward extreme terrain science. Title: Highlights of IAU Commission 29: Recent Advances and Perspectives on Stellar Spectroscopy Authors: Cunha, Katia; Soderblom, David R.; Piskunov, Nikolai; Aoki, Wako; Asplund, Martin; Carpenter, Kenneth G.; Crowther, Paul; Melendez, Jorge; Venn, Kimberly; Hill, Vanessa; Yong, David Bibcode: 2016IAUTA..29..428C Altcode: IAU Commission 29 - Stellar Spectra has been one of the IAU commissions from the onset, until its dissolution at the most recent IAU General Assembly in Honolulu in 2015. This commission belonged to IAU Division G (``Stars and Stellar Physics''), the latter committed with fostering research in stellar astrophysics. Within the general field of stellar astrophysics, stellar spectroscopy plays a key role, as stellar spectra are a powerful tool providing a view into the detailed physical properties of stars and the physical processes occuring within them. Title: Lithium in Open Cluster Red Giants Hosting Substellar Companions Authors: Carlberg, Joleen K.; Smith, Verne V.; Cunha, Katia; Carpenter, Kenneth G. Bibcode: 2016ApJ...818...25C Altcode: 2015arXiv151208558C We have measured stellar parameters, [Fe/H], lithium abundances, rotation, and 12C/13C in a small sample of red giants (RGs) in three open clusters that are each home to a RG star that hosts a substellar companion (SSC) (NGC 2423 3, NGC 4349 127, and BD+12 1917 in M67). Our goal is to explore whether the presence of SSCs influences the Li content. Both 12C/13C and stellar rotation are measured as additional tracers of stellar mixing. One of the companion hosts, NGC 2423 3, is found to be Li-rich with A(Li){}{{NLTE}} = 1.56 dex, and this abundance is significantly higher than the A(Li) of the two comparison stars in NGC 2423. All three SSC hosts have the highest A(Li) and 12C/13C when compared to the control RGs in their respective clusters; however, except for NGC 2423 3, at least one control star has similarly high abundances within the uncertainties. Higher A(Li) could suggest that the formation or presence of planets plays a role in the degree of internal mixing on or before the RG branch. However, a multitude of factors affect A(Li) during the RG phase, and when the abundances of our sample are compared with the abundances of RGs in other open clusters available in the literature, we find that they all fall well within a much larger distribution of A(Li) and 12C/13C. Thus, even the high Li in NGC 2423 3 cannot be concretely tied to the presence of the SSC. Title: The Advanced Spectral Library (ASTRAL): Abundance Analysis of the CP Star HR 465 Authors: Carpenter, Kenneth G.; Nielsen, Krister E.; Kober, Gladys V. Bibcode: 2016AAS...22743401C Altcode: We present the results of a spectrum analysis of the prototypical A-type magnetic CP star HR465. Synthetic spectra, using an non-LTE atmosphere model, were generated to fit high-resolution ultraviolet spectra (1200-3100 A) obtained as a part of the "Advanced Spectral Library (ASTRAL) Project: Hot Stars" program (GO-13346: Ayres PI). The ultraviolet data were supplemented by high resolution optical data recorded at the Nordic Optical Telescope with the SOFIN spectrograph. The optical data was used as a complement to the high line density ultraviolet spectrum and primarily used to derive accurate iron-group element abundances.HR 465 has previously been analyzed using IUE spectra. We revisit the object with this high quality data. Large parts of the spectrum have been synthesized with an ATLAS model (Teff=10750K, logg=4.0) and we present abundance results for more than 50 elements. We can confirm some of the abundance characteristics previously derived from IUE data, where elements heavier than Z=30 show significant abundance enhancements compared to solar values, while some of the lighter elements show abundance deficiencies. We will place these results in context of other AP stars, and the large number of element abundances will also help us to put some constraint on stellar abundance and evolution theories. Title: The Magnetic Coupling of Chromospheres and Winds From Late Type Evolved Stars: Role of MHD Waves Authors: Airapetian, Vladimir; Leake, James; Carpenter, Kenneth Bibcode: 2015IAUGA..2190977A Altcode: Stellar chromospheres and winds represent universal attributes of stars on the cool portion of H-R diagram. In this paper we derive observational constrains for the chromospheric heating and wind acceleration from cool evolved stars and examine the role of Alfven waves as a viable source of energy dissipation and momentum deposition. We use a 1.5D magnetohydrodynamic code with a generalized Ohm's law to study propagation of Alfven waves generated along a diverging magnetic field in a stellar photosphere at a single frequency. We demonstrate that due to inclusion of the effects of ion-neutral collisions in magnetized weakly ionized chromospheric plasma on resistivity and the appropriate grid resolution, the numerical resistivity becomes 1-2 orders of magnitude smaller than the physical resistivity. The motions introduced by non-linear transverse Alfven waves can explain non-thermally broadened and non-Gaussian profiles of optically thin UV lines forming in the stellar chromosphere of α Tau and other late-type giant and supergiant stars. The calculated heating rates in the stellar chromosphere model due to resistive (Joule) dissipation of electric currents on Pedersen resistivity are consistent with observational constraints on the net radiative losses in UV lines and the continuum from α Tau. At the top of the chromosphere, Alfven waves experience significant reflection, producing downward propagating transverse waves that interact with upward propagating waves and produce velocity shear in the chromosphere. Our simulations also suggest that momentum deposition by non-linear Alfven waves becomes significant in the outer chromosphere within 1 stellar radius from the photosphere that initiates a slow and massive winds from red giants and supergiants. Title: The abundance pattern of heavy elements in Sirius: Impact of modern observations (STIS) and improved Atomic data Authors: Ramsay Cowley, Charles; Ayres, Thomas; Wahlgren, Glenn; Carpenter, Kenneth Bibcode: 2015IAUGA..2236931R Altcode: The abundance pattern of heavy elements in Sirius: Impact of modern observations (STIS) and improved atomic data. We determine abundances or upper limits for the 55 stable elements from copper to uranium for the A1 Vm star Sirius. The primary observational material consists of Hubble Space Telescope (HST) spectra taken with the Space Telescope Imaging Spectrograph (STIS) from the ASTRAL project (Ayres 2010, ApJS, 187, 149). We have also used archival material from COPERNICUS (retrieved from the MAST) and from HST/GHRS, as well as the ground-based Furenlid, Westin, and Kurucz Sirius Atlas (FWK). The GHRS observations were described by Wahlgren, et al. (1993, Bull. AAS, 25, 1321). We also used the monumental study of Sirius by Klaus Kohl (1964, Zs. f. Ap. 60, 115, 1964, see also 1964, Das Spektrum des Sirius, 3100 - 8863A, Kiel thesis). Abundance determinations are based on the photospheric model of Landstreet (2011, A&A, 528, 132). The atomic data base is significantly improved since the pioneering work by Sadakane (1988, PASP, 100, 811; 1991, 103, 355). The basic source was VALD3 (http://vald.inasan.ru/~vald3/php/vald.php), supplemented for all species by the essential NIST bibliographic data base (http://physics.nist.gov/cgi-bin/ASBib1/TransProbBib.cgi). We determine abundances and upper limits by synthesizing short wavelength regions around strong lines. Virtually all of the abundance/upper limit results show excesses over the solar composition of between 1 and 2 dex. This result is in general agreement with overall results for metallic line stars, though we have no information on possible severe depletions for most elements. We conclude that the mechanisms causing abundance anomalies in Sirius have not acted to produce the extreme excesses of 4 or more dex (Pt, Hg), or deficiencies (Zn) seen in many HgMn stars.CRC thanks Stefano Bagnulo for the UVESPOP Sirius spectrum. Robert Kurucz was most helpful with older Sirius UV and visual spectra. Title: Fluorescence Processes in the Outer Atmospheres of the Evolved M-Stars Alpha Ori (M2 Iab) and Gamma Cru (M3.4 III) Authors: Carpenter, Kenneth; Kober, Gladys; Nielsen, Krister; Ayres, Thomas; Wahlgren, Glenn Bibcode: 2015IAUGA..2242446C Altcode: The prototypical M-giant and M-supergiant stars, Gamma Cru (M3.4 III)) and Alpha Ori (M2Iab), have been observed as part of the "Advanced Spectral Library (ASTRAL) Project: Cool Stars" (PI = T. Ayres). "ASTRAL-Cool Stars" is an HST Cycle 18 Treasury Program designed to collect, using the Space Telescope Imaging Spectrograph (STIS), a definitive set of representative, high-resolution (R~46,000 in the FUV up to ~1700 Å, R~30,000 for 1700-2150 Å, and R~114,000 >2150 Å) and high signal/noise (S/N>100) UV spectra of eight F-M evolved cool stars. These extremely high-quality UV echelle spectra are available from the HST archive and through the University of Colorado (http://casa.colorado.edu/~ayres/ASTRAL/). In this paper, we use the very rich emission-line spectra of the two evolved M stars in the sample, Gamma Cru (GaCrux) and Alpha Ori (Betelgeuse), to study the fluorescence processes operating in their outer atmospheres. We summarize the pumping transitions and fluorescent line products known on the basis of previous work and newly identified in our on-going analysis of these extraordinary new “Treasury” spectra. Detailed descriptions of selected processes are given to illustrate their operation. The wide variety of fluorescence processes in operation in these outer atmospheres, both molecular and atomic, suggest that there is a mixture of warm and cool plasmas present and that H I Ly-alpha in particular is locally very strong, even though, in the case of Alpha Ori, no flux is seen at earth due to strong circumstellar absorption at that wavelength. Many new fluorescence line products and several new processes have been identified in these spectra, which are more complete and of higher S/N than previously available for these stars. Title: Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report Authors: Spergel, D.; Gehrels, N.; Baltay, C.; Bennett, D.; Breckinridge, J.; Donahue, M.; Dressler, A.; Gaudi, B. S.; Greene, T.; Guyon, O.; Hirata, C.; Kalirai, J.; Kasdin, N. J.; Macintosh, B.; Moos, W.; Perlmutter, S.; Postman, M.; Rauscher, B.; Rhodes, J.; Wang, Y.; Weinberg, D.; Benford, D.; Hudson, M.; Jeong, W. -S.; Mellier, Y.; Traub, W.; Yamada, T.; Capak, P.; Colbert, J.; Masters, D.; Penny, M.; Savransky, D.; Stern, D.; Zimmerman, N.; Barry, R.; Bartusek, L.; Carpenter, K.; Cheng, E.; Content, D.; Dekens, F.; Demers, R.; Grady, K.; Jackson, C.; Kuan, G.; Kruk, J.; Melton, M.; Nemati, B.; Parvin, B.; Poberezhskiy, I.; Peddie, C.; Ruffa, J.; Wallace, J. K.; Whipple, A.; Wollack, E.; Zhao, F. Bibcode: 2015arXiv150303757S Altcode: This report describes the 2014 study by the Science Definition Team (SDT) of the Wide-Field Infrared Survey Telescope (WFIRST) mission. It is a space observatory that will address the most compelling scientific problems in dark energy, exoplanets and general astrophysics using a 2.4-m telescope with a wide-field infrared instrument and an optical coronagraph. The Astro2010 Decadal Survey recommended a Wide Field Infrared Survey Telescope as its top priority for a new large space mission. As conceived by the decadal survey, WFIRST would carry out a dark energy science program, a microlensing program to determine the demographics of exoplanets, and a general observing program utilizing its ultra wide field. In October 2012, NASA chartered a Science Definition Team (SDT) to produce, in collaboration with the WFIRST Study Office at GSFC and the Program Office at JPL, a Design Reference Mission (DRM) for an implementation of WFIRST using one of the 2.4-m, Hubble-quality telescope assemblies recently made available to NASA. This DRM builds on the work of the earlier WFIRST SDT, reported by Green et al. (2012) and the previous WFIRST-2.4 DRM, reported by Spergel et. (2013). The 2.4-m primary mirror enables a mission with greater sensitivity and higher angular resolution than the 1.3-m and 1.1-m designs considered previously, increasing both the science return of the primary surveys and the capabilities of WFIRST as a Guest Observer facility. The addition of an on-axis coronagraphic instrument to the baseline design enables imaging and spectroscopic studies of planets around nearby stars. Title: Comparing Vent Surface Geometry with Its Subsurface Structure Authors: Parcheta, C.; Parness, A.; Nash, J.; Wiltsie, N.; Carpenter, K.; Mitchell, K. L. Bibcode: 2015LPI....46.1649P Altcode: 2015LPICo1832.1649P Magma conduit./Shape is vital yet unknown./How does it erupt? Title: The HST Treasury ``Advanced Spectral Library'' (ASTRAL) Programs Authors: Carpenter, Kenneth G.; Ayres, Thomas R. Bibcode: 2015csss...18.1041C Altcode: 2014arXiv1411.1419C The ``Advanced Spectral Library (ASTRAL)'' Project (PI = T. Ayres) consists of two Treasury Programs: the Cycle 18 ``Cool Stars'' (GO-12278) Program and the Cycle 21 ``Hot Stars'' (GO-13346) Program. The primary goal of these programs is to collect, for the use of the astronomical community over the coming decades, a definitive set of representative, high-resolution (R∼30,000-100,000), high signal/noise (S/N>100) spectra, with full UV coverage (∼1150 - 3100 Å) of prototypical stars across the HR diagram, utilizing the high-performance Space Telescope Imaging Spectrograph (STIS). The Cycle 18 program obtained spectra of 8 F-M evolved late-type stars, while the Cycle 21 program is in the process of observing 21 early-type stars, which span a broad range of spectral types between early-O and early-A. All of these data will be available from the HST archive and, in post-processed and merged form, at http://casa.colorado.edu/ãyres/ASTRAL/. These data will enable investigations of a broad range of problems - stellar, interstellar, and beyond - for many years into the future. We describe here the details of the observing programs, including the program targets and the observing strategies utilized to optimize the quality of the spectra, and present some illustrative examples of the on-going scientific analyses, including a study of the outer atmospheres and winds of the two evolved M stars in the sample and a first look at a ``high definition'' UV spectrum of a magnetic chemically peculiar ``Ap'' star. Title: Mining the HST "Advanced Spectral Library (ASTRAL)": Winds of the Evolved M Stars Alpha Ori (M2 Iab) and Gamma Cru (M3.4 III) Authors: Carpenter, Kenneth G.; Nielsen, Krister E.; Kober, Gladys V.; Ayres, Thomas R. Bibcode: 2015AAS...22534408C Altcode: The "Advanced Spectral Library (ASTRAL) Project: Cool Stars" (PI = T. Ayres) is an HST Cycle 18 Treasury Program that collected a definitive set of representative, high-resolution (R=30,000-100,000) and high signal/noise (S/N>100) UV spectra of eight F-M evolved cool stars. These extremely high-quality STIS UV echelle spectra are available from the HST archive and through the ASTRAL website at the University of Colorado at http://casa.colorado.edu/~ayres/ASTRAL/ and will enable investigations of a broad range of problems -- stellar, interstellar, and beyond -- for many years. In this paper, we examine the wealth of wind diagnostics contained in the very rich spectra of the two evolved M stars in the sample, the M3.4 III giant Gamma Crucis (GaCrux) and the M2 Iab supergiant Alpha Orionis (Betelgeuse) and characterize the winds at the time of these STIS observations in 2011 and compare the results with those obtained from more limited data taken at earlier epochs with HST/GHRS and IUE. In particular we study the variation of the numerous Fe II profiles with intrinsic strength in the two stars. The shifting wavelengths of the wind absorptions relative to the emission peaks and the changes in relative strengths of the emission peaks reflect the acceleration of the wind from the base of the chromosphere. Although the characteristics of the Gamma Cru wind are relatively stable with time, the Alpha Ori wind outflow appears significantly smaller than seen by Carpenter et al. (1997, ApJ, 479, 970) in GHRS observations taken in 1992 (and in earlier IUE observations). There might in fact be evidence in these STIS spectra that the outflow has turned into an inflow, as reported at epochs prior to IUE by Boesgaard and Magnan (1975 ApJ 198, 369) and Boesgaard (1979 ApJ 232, 485) based on a limited number of lines in the extreme blue end of ground-based spectra. Title: Toward A Self Consistent MHD Model of Chromospheres and Winds From Late Type Evolved Stars Authors: Airapetian, V. S.; Leake, J. E.; Carpenter, Kenneth G. Bibcode: 2015csss...18..269A Altcode: 2014arXiv1409.3833A We present the first magnetohydrodynamic model of the stellar chromospheric heating and acceleration of the outer atmospheres of cool evolved stars, using α Tau as a case study. We used a 1.5D MHD code with a generalized Ohm's law that accounts for the effects of partial ionization in the stellar atmosphere to study Alfvén wave dissipation and wave reflection. We have demonstrated that due to inclusion of the effects of ion-neutral collisions in magnetized weakly ionized chromospheric plasma on resistivity and the appropriate grid resolution, the numerical resistivity becomes 1-2 orders of magnitude smaller than the physical resistivity. The motions introduced by non-linear transverse Alfvé waves can explain non-thermally broadened and non-Gaussian profiles of optically thin UV lines forming in the stellar chromosphere of α Tau and other late-type giant and supergiant stars. The calculated heating rates in the stellar chromosphere due to resistive (Joule) dissipation of electric currents, induced by upward propagating non-linear Alfvé waves, are consistent with observational constraints on the net radiative losses in UV lines and the continuum from α Tau. At the top of the chromosphere, Alfvé waves experience significant reflection, producing downward propagating transverse waves that interact with upward propagating waves and produce velocity shear in the chromosphere. Our simulations also suggest that momentum deposition by non-linear Alfvé waves becomes significant in the outer chromosphere at 1 stellar radius from the photosphere. The calculated terminal velocity and the mass loss rate are consistent with the observationally derived wind properties in α Tau. Title: An HST COS "SNAPshot" Spectrum of the K Supergiant λ Vel (K4Ib-II) Authors: Carpenter, Kenneth G.; Ayres, Thomas R.; Harper, Graham M.; Kober, Gladys; Nielsen, Krister E.; Wahlgren, Glenn M. Bibcode: 2014ApJ...794...41C Altcode: We present a far-ultraviolet spectrum of the K4 Ib-II supergiant λ Vel obtained with the Hubble Space Telescope's Cosmic Origins Spectrograph (COS) as a part of the SNAPshot program "SNAPing coronal iron" (GO 11687). The observation covers a wavelength region (1326-1467 Å) not previously recorded for λ Vel at a spectral resolving power of R ~ 20,000 and displays strong emission and absorption features, superposed on a bright chromospheric continuum. Fluorescent excitation is responsible for much of the observed emission, mainly powered by strong H I Lyα and the O I (UV 2) triplet emission near λ1304. The molecular CO and H2 fluorescences are weaker than in the early-K giant α Boo while the Fe II and Cr II lines, also pumped by H I Lyα, are stronger in λ Vel. This pattern of relative line strengths between the two stars is explained by the lower iron-group element abundance in α Boo, which weakens that star's Fe II and Cr II emission without reducing the molecular fluorescences. The λ Vel spectrum shows fluorescent Fe II, Cr II, and H2 emission similar to that observed in the M supergiant α Ori, but more numerous well-defined narrow emissions from CO. The additional CO emissions are visible in the spectrum of λ Vel since that star does not have the cool, opaque circumstellar shells that surround α Ori and produce broad circumstellar CO (A-X) band absorptions that hide those emissions in the cooler star. The presence of Si IV emission in λ Vel indicates a ~8 × 104 K plasma that is mixed into the cooler chromosphere. Evidence of the stellar wind is seen in the C II λλ1334,1335 lines and in the blueshifted Fe II and Ni II wind absorption lines. Line modeling using Sobolev with Exact Integration for the C II lines indicates a larger terminal velocity (~45 versus ~30 km s-1) and turbulence (~27 versus <21 km s-1) with a more quickly accelerating wind (β = 0.35 versus 0.7) at the time of this COS observation in 2010 than derived from Goddard High Resolution Spectrograph data obtained in 1994. The Fe II and Ni II absorptions are blueshifted by 7.6 km s-1 relative to the chromospheric emission, suggesting formation in lower levels of the accelerating wind and their widths indicate a higher turbulence in the λ Vel wind compared to α Ori.

Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. Title: Interferometer evolution: imaging terras after building 'little' experiments (INEVITABLE) Authors: Rinehart, S.; Carpenter, K.; van Belle, G.; Unwin, S. Bibcode: 2014SPIE.9146E..17R Altcode: Perhaps one of the most ambitious long-term goals of the astronomical community is to map distant exoplanets. This will require instruments that provide sufficient angular resolution to place multiple pixels across an image of an exoplanet. Many other science programs also require orders of magnitude improvement in angular resolution, and for all of these, single aperture telescopes are impractical. In fact, the array of scientific goals that require high angular resolution makes interferometry inevitable. Here, we discuss some of the long-term science needs, and the implications for future interferometers, and then talk about some possible paths towards these future missions. Title: Mining the HST "Advanced Spectral Library (ASTRAL) - Hot Stars": The High Definition UV Spectrum of the Ap Star HR 465 Authors: Carpenter, Kenneth G.; Ayres, T. R.; Nielsen, K. E.; Kober, G. V.; Wahlgren, G. M.; Adelman, S. J.; Cowley, C. R. Bibcode: 2014AAS...22315105C Altcode: The "Advanced Spectral Library (ASTRAL) Project: Hot Stars" is a Hubble Space Telescope (HST) Cycle 21 Treasury Program (GO-13346: Ayres PI). It is designed to collect a definitive set of representative, high-resolution ( 30,000-100,000), high signal/noise (S/N>100), and full UV coverage 1200 - 3000 A) spectra of 21 early-type stars, utilizing the high-performance Space Telescope Imaging Spectrograph (STIS). The targets span the range of spectral types between early-O and early-A, including both main sequence and evolved stars, fast and slow rotators, as well as chemically peculiar (CP) and magnetic objects. These extremely high-quality STIS UV echelle spectra will be available from the HST archive and, in post-processed and merged form, at http://casa.colorado.edu ayres/ASTRAL/. The UV "atlases" produced by this program will enable investigations of a broad range of problems -- stellar, interstellar, and beyond -- for many years to come. We offer a first look at one of the earliest datasets to come out of this observing program, a "high definition" UV spectrum of the Ap star HR 465, which was chosen as a prototypical example of an A-type magnetic CP star. HR 465 has a global magnetic field of ~2200 Gauss. Earlier analyses of IUE spectra show strong iron-peak element lines, along with heavy elements such as Ga and Pt, while being deficient in the abundance of some ions of low atomic number, such as carbon. We demonstrate the high quality of the ASTRAL data and present the identification of spectral lines for a number of elements. By comparison of the observed spectra with calculated spectra, we also provide estimates of element abundances, emphasizing heavy elements, and place these measurements in the context of earlier results for this and other Ap stars. Title: Evolution of Stellar Coronae: From the Sun to a Red Giant Authors: Airapetian, Vladimir; Leake, J. E.; Carpenter, K. G. Bibcode: 2014AAS...22342401A Altcode: All stars in the H-R diagram later than spectral class F5 possess a convective zone that provides a reservoir of mechanical energy to drive activity in layers above the photosphere and to shape its atmospheric structures. Cool stars on the main sequence are characterized by compact chromospheres/transition regions and extended coronae transitioning into stellar winds. As the star exhausts its hydrogen fuel and enters into a giant/supergiant phase of its life, its atmospheric structures change dramatically showing signatures of bloated chromospheres and compact coronae. What physical mechanisms are responsible for such a drastic transition from a "dwarf" chromosphere of a cool dwarf star into a "giant" chromosphere of an evolved giant? How does a "giant" corona of a dwarf star evolve into a "dwarf" corona" of a giant star? In this talk we present a unified picture of the evolution of stellar atmospheric structures as a cool stars moves from the main-sequence to a red giant phase. The results of our 2.5D magnetohydrodynamic (MHD) simulations suggest the dynamics of the emergence of magnetic flux into the atmospheres of cool stars is strongly dependent on surface gravity and the magnetic field. We simulate the dynamics of emergence of magnetic field in the Sun, a sug-giant and a giant star. Our simulations suggest that as the surface gravity becomes smaller and the magnetic field weaker as the star evolves, the magnetic flux cannot be transported high enough into the atmosphere to form an extended corona. Instead, it forms highly compact loops in the lower layers of bloated stellar chromospheres and heated by Alfven waves to coronal temperatures. Title: Using ISS telescopes for electromagnetic follow-up of gravitational wave detections of NS-NS and NS-BH mergers Authors: Camp, J.; Barthelmy, S.; Blackburn, L.; Carpenter, K. G.; Gehrels, N.; Kanner, J.; Marshall, F. E.; Racusin, J. L.; Sakamoto, T. Bibcode: 2013ExA....36..505C Altcode: 2013arXiv1304.3705C; 2013ExA...tmp...31C The International Space Station offers a unique platform for rapid and inexpensive deployment of space telescopes. A scientific opportunity of great potential later this decade is the use of telescopes for the electromagnetic follow-up of ground-based gravitational wave detections of neutron star and black hole mergers. We describe this possibility for OpTIIX, an ISS technology demonstration of a 1.5 m diffraction limited optical telescope assembled in space, and ISS-Lobster, a wide-field imaging X-ray telescope now under study as a potential NASA mission. Both telescopes will be mounted on pointing platforms, allowing rapid positioning to the source of a gravitational wave event. Electromagnetic follow-up rates of several per year appear likely, offering a wealth of complementary science on the mergers of black holes and neutron stars. Title: Sorptive fractionation of organic matter and formation of organo-hydroxy-aluminum complexes during litter biodegradation in the presence of gibbsite Authors: Heckman, K.; Grandy, A. S.; Gao, X.; Keiluweit, M.; Wickings, K.; Carpenter, K.; Chorover, J.; Rasmussen, C. Bibcode: 2013GeCoA.121..667H Altcode: Solid and aqueous phase Al species are recognized to affect organic matter (OM) stabilization in forest soils. However, little is known about the dynamics of formation, composition and dissolution of organo-Al hydroxide complexes in microbially-active soil systems, where plant litter is subject to microbial decomposition in close proximity to mineral weathering reactions. We incubated gibbsite-quartz mineral mixtures in the presence of forest floor material inoculated with a native microbial consortium for periods of 5, 60 and 154 days. At each time step, samples were density separated into light (<1.6 g cm-3), intermediate (1.6-2.0 g cm-3), and heavy (>2.0 g cm-3) fractions. The light fraction was mainly comprised of particulate organic matter, while the intermediate and heavy density fractions contained moderate and large amounts of Al-minerals, respectively. Multi-method interrogation of the fractions indicated the intermediate and heavy fractions differed both in mineral structure and organic compound composition. X-ray diffraction analysis and SEM/EDS of the mineral component of the intermediate fractions indicated some alteration of the original gibbsite structure into less crystalline Al hydroxide and possibly proto-imogolite species, whereas alteration of the gibbsite structure was not evident in the heavy fraction. DRIFT, Py-GC/MS and STXM/NEXAFS results all showed that intermediate fractions were composed mostly of lignin-derived compounds, phenolics, and polysaccharides. Heavy fraction organics were dominated by polysaccharides, and were enriched in proteins, N-bearing compounds, and lipids. The source of organics appeared to differ between the intermediate and heavy fractions. Heavy fractions were enriched in 13C with lower C/N ratios relative to intermediate fractions, suggesting a microbial origin. The observed differential fractionation of organics among hydroxy-Al mineral types suggests that microbial activity superimposed with abiotic mineral-surface-mediated fractionation leads to strong density differentiation of organo-mineral complex composition even over the short time scales probed in these incubation experiments. The data highlight the strong interdependency of mineral transformation, microbial community activity, and organic matter stabilization during biodegradation. Title: Tracing Magnetic "Active Regions" in Non-Coronal and Hybrid Cool Giants Authors: Airapetian, Vladimir; Carpenter, K. G. Bibcode: 2013giec.conf10305A Altcode: FUSE and HST/STIS and GHRS observations of a number of non-coronal and hybrid giants reveal dynamics processes in their atmospheres. The observed variations in the fluxes, non-thermal broadening, and shifts of selected UV chromospheric emission lines provide a powerful diagnostic tool to characterize the total unsigned magnetic flux and its rotational modulation in cool giant stars, as well as the energy dissipation and momentum deposition in their atmospheres. We utilize a new empirical method, based on our numerical model of Alfvén wave-driven winds from evolved stars, to detect and characterize the signatures of the rotational modulation of magnetic "active regions" in two evolved giant stars, representative of both hybrid and non-coronal (K5 III) stars. Specifically, we derive the properties of chromospheric motions and heating rates at two or more epochs for each star. We use archival FUSE, HST/GHRS and HST/STIS observations to address a fundamental question in the evolution of magnetic dynamos in late-type giant stars, namely: what is the inter-relationship between chromospheric turbulence, magnetic flux, and the wind properties in cool, evolved stars? Title: The Role of Alfvén Waves in Atmospheric Dynamics of Non-Coronal, Hybrid and Coronal Giants Authors: Airapetian, Vladimir; Carpenter, K. G.; Evans, R. M. Bibcode: 2013giec.conf30102A Altcode: In this talk, we discuss the properties of atmospheric heating and wind dynamics from non-coronal, hybrid and coronal giants described by an Alfvén-wave driven model of stellar atmospheres. Specifically, we present the results of numerical simulations of winds from non-coronal and hybrid evolved giant stars using a fully nonlinear, time-dependent 2.5-dimensional magnetohydrodynamic (MHD) code. This study extends our previous fully nonlinear MHD wind simulations to include a broadband frequency spectrum of Alfvén waves that drive winds from red giant stars. We discuss four Alfven wind models that cover the whole range of the Alfvén wave frequency spectrum to characterize the role of freely propagated and reflected Alfvén waves in the gravitationally stratified atmosphere of a late-type giant star. Our simulations demonstrate that, unlike linear Alfvén wave-driven wind models, a stellar wind model based on plasma acceleration due to broadband non-linear Alfvén waves can consistently reproduce the wide range of radial velocity profiles of the winds, their terminal velocities, and the observed mass loss rates observed in non-coronal and hybrid giants. We also present the recent results of simulations of the thermodynamics and dynamics of the atmosphere of a magnetically active coronal giant, β Ceti, by applying a 3D MHD code, BATRUS, that incorporates a self-consistent treatment of energy dissipation due Alfvén wave turbulence, thermal conduction and radiative cooling terms. Title: Signatures of Rotational Modulation of Magnetic "Active Regions" in Hybrid and Non-coronal Cool Giant Stars Authors: Carpenter, Kenneth G.; Airapetian, V. Bibcode: 2013AAS...22211614C Altcode: Observations of the variations in the fluxes, non-thermal broadening, and shifts of selected UV chromospheric emission lines provide a powerful diagnostic tool to characterize the total unsigned magnetic flux and its rotational modulation in cool giant stars, as well as the energy dissipation and momentum deposition in their atmospheres. We utilize a new empirical method, based on our 2.5D MHD model of Alfvén wave-driven winds from evolved stars, to detect and characterize the signatures of the rotational modulation of magnetic "active regions" in two evolved giant stars, representative of both hybrid and non-coronal (K5 III) stars. Specifically, we derive the properties of chromospheric motions and heating rates at two or more epochs for each star. We use archival HST/GHRS and HST/STIS observations to address a fundamental question in the evolution of magnetic dynamos in late-type giant stars, namely: what is the inter-relationship between chromospheric turbulence, magnetic flux, and the wind properties in cool, evolved stars? Title: Mining the Advanced Spectral Library (ASTRAL): Characterizing Winds of Evolved M-Stars Authors: Nielsen, Krister E.; Carpenter, K. G.; Kober, G. V.; Cheng, K.; Ayres, T. R.; Harper, G. Bibcode: 2013AAS...22135102N Altcode: The HST/STIS treasury program Advanced Spectral Library (ASTRAL) enables investigations of the character and dynamics of the wind and chromosphere of cool stars, using high quality spectral data. This paper present the analysis of the outflowing winds of the M3.4 giant Gamma Cru and the M2Iab supergiant Alpha Ori. The outer atmospheres of these objects show strong evidence for significant inhomogeneity in their thermal and kinematic structure, and are in general not well understood. The wind features are characterized by a strong chromospheric emission suppressed by a overlying wind absorption, for many transitions producing a double peak feature. The relative strengths and wavelength shifts between the absorption and emission components of the lines reflect the acceleration of the wind from the base of the chromosphere, as the self-absorption is due to the overlying wind absorption, whose velocity relative to the chromosphere varies with height and thus line opacity. The wind profiles are sensitive to the wind opacity, turbulence and flow velocity, and hence favorable to analyze with the Sobolev source function with Exact Integration of the transfer equation (SEI) code. This paper will show a velocity and intensity analysis of the wind profiles and modeling with the SEI code to derive an improved set of wind parameters, primarily, for Gamma Cru. Title: Mining the Advanced Spectral Library (ASTRAL): Fluorescence in Evolved M-Stars Authors: Carpenter, Kenneth G.; Nielsen, K. E.; Kober, G. V.; Cheng, K.; Ayres, T. R.; Wahlgren, G. M.; Harper, G. Bibcode: 2013AAS...22135101C Altcode: The "Advanced Spectral Library (ASTRAL) Project: Cool Stars" (PI = T. Ayres) is an HST Cycle 18 Treasury Program designed to collect a definitive set of representative, high-resolution ( 46,000 in the FUV up to ~1700 Å, 30,000 for 1700-2150 Å, and 114,000 >2150 Å) and high signal/noise (S/N>100) UV spectra of eight F-M evolved cool stars. These extremely high-quality STIS UV echelle spectra are available from the HST archive and through the University of Colorado (http://casa.colorado.edu ayres/ASTRAL/) and will enable investigations of a broad range of problems -- stellar, interstellar, and beyond -- for many years. In this paper, we use the very rich emission-line spectra of the two evolved M stars in the sample, the M3.4 giant Gamma Crucis (GaCrux) and the M2Iab supergiant Alpha Orionis (Betelgeuse), to study the fluorescence processes operating in their outer atmospheres. We summarize the pumping transitions and fluorescent line products known on the basis of previous work (e.g. Carpenter 1988 and references therein) and newly identified in our current, on-going analysis and provide some comments on their implications for the structure of the outer atmospheres of these stars. Title: Using the ISS as a testbed to prepare for the next generation of space-based telescopes Authors: Postman, Marc; Sparks, William B.; Liu, Fengchuan; Ess, Kim; Green, Joseph; Carpenter, Kenneth G.; Thronson, Harley; Goullioud, Renaud Bibcode: 2012SPIE.8442E..1TP Altcode: The infrastructure available on the ISS provides a unique opportunity to develop the technologies necessary to assemble large space telescopes. Assembling telescopes in space is a game-changing approach to space astronomy. Using the ISS as a testbed enables a concentration of resources on reducing the technical risks associated with integrating the technologies, such as laser metrology and wavefront sensing and control (WFS&C), with the robotic assembly of major components including very light-weight primary and secondary mirrors and the alignment of the optical elements to a diffraction-limited optical system in space. The capability to assemble the optical system and remove and replace components via the existing ISS robotic systems such as the Special Purpose Dexterous Manipulator (SPDM), or by the ISS Flight Crew, allows for future experimentation as well as repair if necessary. In 2015, first light will be obtained by the Optical Testbed and Integration on ISS eXperiment (OpTIIX), a small 1.5-meter optical telescope assembled on the ISS. The primary objectives of OpTIIX include demonstrating telescope assembly technologies and end-to-end optical system technologies that will advance future large optical telescopes. Title: Commission 29: Stellar Spectra Authors: Piskunov, Nikolai; Cunha, Katia; Parthasarathy, Mudumba; Aoki, Wako; Asplund, Martin; Bohlender, David; Carpenter, Kenneth; Melendez, Jorge; Rossi, Silvia; Smith, Verne; Soderblom, David; Wahlgren, Glenn Bibcode: 2012IAUTA..28..157P Altcode: Commission 29 consists of members of the International Astronomical Union carrying out theoretical and observational studies of stars using spectroscopy, developing instrumentation for spectroscopy and producing and collecting data for interpretation of spectra. Title: Harnessing the Power of NASA's Kepler Mission for Understanding Stellar Activity and Enhancing Planet Discovery Authors: Bastien, Fabienne A.; Stassun, K. G.; Pepper, J.; Walkowicz, L.; Basri, G.; Carpenter, K. G. Bibcode: 2012AAS...21934504B Altcode: The magnetic activity of stars, which often manifests itself in the form of starspots, can induce short-timescale photometric variability, thereby adding to the difficulty of detecting planets, particularly those in the Earth mass range. Indeed, photometric "noise” caused by stellar magnetic activity can preclude the detection of the tiny transit signature that a planet like ours would produce. Hence, in order to successfully detect Earth-like planets via the transit method, the exoplanet community needs a way characterize the photometric stability of a star in advance. The goal of our project is to empirically relate chromospheric activity and photometric variability for a large sample of stars, spanning a range of stellar masses and evolutionary states, in order to develop an index that is predictive of stellar photometric variability. The inclusion of stars with a range of known rotation periods, as well as subgiants, giants, and Kepler asteroseismology targets, will allow us to more finely examine the relationship between a star's age and its magnetic activity. This work will aid in a fundamental understanding of the physics of magnetic activity in solar-type stars. We acknowledge support through NSF PAARE grant AST-0849736. Title: The Amazing COS FUV (1320 - 1460 Å) Spectrum of λ Vel (K4Ib-II)1 Authors: Carpenter, K. G.; Ayres, T.; Brown, A.; Harper, G. M.; Wahlgren, G. M. Bibcode: 2011ASPC..448.1083C Altcode: 2011csss...16.1083C The FUV spectrum (1320-1460 Å) of the K4 Ib-II supergiant λ Vel was observed with the Cosmic Origins Spectrograph (COS) on HST, as part of the Ayres and Redfield Cycle 17 SNAP program "SNAPing Coronal Iron." This spectrum covers a region not previously recorded in λ Vel at high resolution and, in a mere 20 minutes of exposure, reveals an amazing treasure trove of information. It shows a wide variety of strong emission lines and multiple absorption lines, superposed on a bright chromospheric continuum, with contributions from both atomic and molecular species. These features provide diagnostics of the chromosphere and wind of the star, and by comparison with spectra of stars of similar Teff and/or geff, will improve our knowledge of the heating processes in the chromospheres and the forces driving the stellar wind in cool evolved stars. We present the details of this spectrum, in comparison with stars of similar temperature or luminosity, and discuss our initial interpretation of the data. Title: The Stellar Imager (SI) - A Mission to Resolve Stellar Surfaces, Interiors, and Magnetic Activity Authors: Christensen-Dalsgaard, Jørgen; Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska, Margarita; Si Team Bibcode: 2011JPhCS.271a2085C Altcode: The Stellar Imager (SI) is a space-based, UV/Optical Interferometer (UVOI) designed to enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and of the Universe in general. It will also probe via asteroseismology flows and structures in stellar interiors. SI will enable the development and testing of a predictive dynamo model for the Sun, by observing patterns of surface activity and imaging of the structure and differential rotation of stellar interiors in a population study of Sun-like stars to determine the dependence of dynamo action on mass, internal structure and flows, and time. SI's science focuses on the role of magnetism in the Universe and will revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. SI is a "Landmark/Discovery Mission" in the 2005 Heliophysics Roadmap, an implementation of the UVOI in the 2006 Astrophysics Strategic Plan, and a NASA Vision Mission ("NASA Space Science Vision Missions" (2008), ed. M. Allen). We present here the science goals of the SI Mission, a mission architecture that could meet those goals, and the technology development needed to enable this mission. Additional information on SI can be found at: http://hires.gsfc.nasa.gov/si/. Title: λ Vel (K4 Ib-II): Fluorescence on a PAR with Other Luminaries Authors: Wahlgren, G. M.; Carpenter, K. G.; Ayres, T. R.; Brown, A.; Harper, G. M. Bibcode: 2011AAS...21715406W Altcode: 2011BAAS...4315406W The ultraviolet spectral region of cool, luminous stars contains emission features that originate from fluorescent mechanisms via PAR (photo-excitation by accidental resonance). These mechanisms can account for numerous emission lines, downward transitions from upper energy levels pumped by strong transitions, such as H Ly-α, O I 1302, C II 1335, and Mg II h&k. A new, high S/N observation of the cool giant star λ Vel (K4 Ib-II) was obtained with the HST/COS instrument at a resolving power of R 20000 and covers the wavelength region from 132 nm to 147 nm. High-quality spectra (COS and GHRS) are now available from 128 nm to 147 nm, and at 12 moderate and high resolution observations from the HST/GHRS, the latter covering approximately a third of the wavelength interval from 189 nm to 285 nm. Using these data, together with observations from FUSE and IUE, we investigate PAR processes in the spectra of Cr II and Fe II and make comparisons with other stars. The presence of additional atomic (O I, S I, and Cl I) and molecular (H2, CO) PAR processes in the spectrum of λ Vel is briefly discussed. Title: The Chromospheric Structure and Wind of the K-Supergiant Lambda Velorum Authors: Carpenter, Kenneth G.; Ayres, T. R.; Brown, A.; Harper, G. M.; Wahlgren, G. M. Bibcode: 2011AAS...21715407C Altcode: 2011BAAS...4315407C Recently, the 1326-1466 Å region of the FUV spectrum of the K4 Ib-II supergiant Lambda Vel was observed with the Cosmic Origins Spectrograph (COS) on HST, as part of the Ayres and Redfield Cycle 17 SNAP program "SNAPing Coronal Iron.” This spectrum covers a region not previously recorded in Lambda Vel at high resolution and, in a mere 20 minutes of exposure, reveals an amazing treasure trove of information. It shows a wide variety of strong atomic and molecular emission lines formed in the chromosphere and multiple atomic absorption lines formed in the stellar wind, both superposed on a bright chromospheric continuum. Further evidence of the stellar wind is seen in the P Cygni profiles presented by the C II (UV 1) lines near 1335 Å. We combine this COS data with archival GHRS spectra of other selected FUV and NUV regions to better characterize the outer atmospheric structure of the star and its massive, outflowing wind. Title: Winds from Luminous Late-type Stars. II. Broadband Frequency Distribution of Alfvén Waves Authors: Airapetian, V.; Carpenter, K. G.; Ofman, L. Bibcode: 2010ApJ...723.1210A Altcode: 2010arXiv1008.3955A We present the numerical simulations of winds from evolved giant stars using a fully nonlinear, time-dependent 2.5-dimensional magnetohydrodynamic (MHD) code. This study extends our previous fully nonlinear MHD wind simulations to include a broadband frequency spectrum of Alfvén waves that drive winds from red giant stars. We calculated four Alfvén wind models that cover the whole range of the Alfvén wave frequency spectrum to characterize the role of freely propagated and reflected Alfvén waves in the gravitationally stratified atmosphere of a late-type giant star. Our simulations demonstrate that, unlike linear Alfvén wave-driven wind models, a stellar wind model based on plasma acceleration due to broadband nonlinear Alfvén waves can consistently reproduce the wide range of observed radial velocity profiles of the winds, their terminal velocities, and the observed mass-loss rates. Comparison of the calculated mass-loss rates with the empirically determined mass-loss rate for α Tau suggests an anisotropic and time-dependent nature of stellar winds from evolved giants. Title: Stellar Imager (SI): developing and testing a predictive dynamo model for the Sun by imaging other stars Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska, Margarita; Kraemer, Steve; Lyon, Richard; Mozurkewich, David; Airapetian, Vladimir; Adams, John C.; Allen, Ronald J.; Brown, Alex; Bruhweiler, Fred; Conti, Alberto; Christensen-Dalsgaard, Joergen; Cranmer, Steve; Cuntz, Manfred; Danchi, William; Dupree, Andrea; Elvis, Martin; Evans, Nancy; Giampapa, Mark; Harper, Graham; Hartman, Kathy; Labeyrie, Antoine; Leitner, Jesse; Lillie, Chuck; Linsky, Jeffrey L.; Lo, Amy; Mighell, Ken; Miller, David; Noecker, Charlie; Parrish, Joe; Phillips, Jim; Rimmele, Thomas; Saar, Steve; Sasselov, Dimitar; Stahl, H. Philip; Stoneking, Eric; Strassmeier, Klaus; Walter, Frederick; Windhorst, Rogier; Woodgate, Bruce; Woodruff, Robert Bibcode: 2010arXiv1011.5214C Altcode: The Stellar Imager mission concept is a space-based UV/Optical interferometer designed to resolve surface magnetic activity and subsurface structure and flows of a population of Sun-like stars, in order to accelerate the development and validation of a predictive dynamo model for the Sun and enable accurate long-term forecasting of solar/stellar magnetic activity. Title: Commission 29: Stellar Spectra Authors: Piskunov, Nikolai; Cunha, Katia; Parthasarathy, Mudumba; Aoki, Wako; Asplund, Martin; Bohlender, David; Carpenter, Kenneth; Melendez, Jorge; Parthasarathy, Mudumba; Rossi, Silvia; Smith, Verne; Soderblom, David; Wahlgren, Glenn Bibcode: 2010IAUTB..27..193P Altcode: The business meeting was attended by 23 members of the Commission. The meeting started at 16:00 a short report of the activities during the triennium 2006-2009. The focus of the activities was the sharing of expertise between spectroscopic techniques in various areas of astronomical research. In particular, the progress in instrumentation, detectors, data reduction, data analysis and archiving. The second activity was the analysis of to IAU meeting proposals followed by recommendations for improvements and eventually support. The sponsored symposia included Sponsoring symposia The Ages of Stars and The Disk Galaxy Evolution in the Cosmological Context. The Commission was also disseminating information about the Commission activities and relevant meetings to the Commission members. In this respect the Commission web page is playing a crucial role. Title: 2.5d Mhd Simulations Of Winds From Red Giants Stars: Broadband Alfvén Waves Authors: Airapetian, Vladimir; Carpenter, K.; Ofman, L. Bibcode: 2010AAS...21542703A Altcode: 2010BAAS...42..342A We present the numerical simulations of winds from evolved giant stars using a fully non-linear, time dependent, 2.5-dimensional magnetohydrodynamic (MHD) code. This study extends our previous fully non-linear MHD wind simulations to the parameter space that describes winds from red giant stars. In the current version of this Alfvén wave driven model, a wind is driven by randomly generated low-frequency non-linear Alfvén waves in a broadband frequency range at the base of the wind. We simulate freely propagated and partially reflected Alfvén waves in the gravitationally stratified atmosphere of a late-type giant star, in a self-consistent manner, until a steady-state wind is formed. Our simulations demonstrate that, unlike linear Alfven wave-driven wind models, a stellar wind model based on plasma acceleration due to low frequency broad-band non-linear Alfvén waves, can consistently reproduce the observed radial velocity profiles of the winds, their terminal velocities, the turbulent broadening of UV lines emitted from those winds and the observed mass loss rates. We find that conversion of non-linear transverse Alfvén waves into longitudinal magnetosonic waves plays the major role in depositing momentum and energy into the stellar wind. The fitting of mass-loss rates from α Tau with the predicted rate suggests a highly anisotropic stellar wind in this evolved giant. The model also predicts a variation of the wind mass-loss rates on time scales of 1 month. Title: The Stellar Commodity Market: Cu, Ag, And Au In The Sun And Solar-type Stars Authors: Wahlgren, Glenn Michael; Carpenter, K. G.; Nave, G. Bibcode: 2010AAS...21542705W Altcode: 2010BAAS...42..343W The elements copper, silver and gold occupy the same column of the periodic table and share the property that their only stable isotopes are odd-numbered, which implies a need for hyperfine structure data when analyzing their spectral lines. A comparison of their solar photospheric abundances with the standard meteoritic element abundances shows that for two of them (Ag, Au) the differences are as large as or larger than the sum of the uncertainties. With some exceptions, the study of the chemical composition of most stars stops at the end of the iron group of elements. Heavier elements are typically not analyzed, often due to the lack of accurate atomic line data. While the post iron-group elements make a small contribution to the total abundance one can argue that, for many reasons, life on earth would not be the same without copper, silver and gold.

We first revisit the abundances of these elements in the solar photosphere, accounting for the revisions in atomic data since these elements were last analyzed in the photosphere. The hyperfine structure of Cu I and Ag I is included in our synthetic spectrum calculations. The spectra Cu I and Cu II are of current interest to us for the determination of hfs constants based on our new laboratory Fourier transform spectrometer data. We then determine the abundances for these elements in the high-resolution spectra for a sample of solar-like stars, obtained from on-line data bases, using synthetic spectrum techniques. The analysis aims to determine the abundance dispersion of these elements in solar-like stars in the solar neighborhood. Some of these stars are known to possess exo-planets, and the abundances of these elements will be correlated with host star metallicity. In general, we aim to encourage a more extensive use of the periodic table for stellar astrophysics. Title: The Stellar Imager (SI) - A Mission to Resolve Stellar Surfaces, Interiors, and Magnetic Activity Authors: Carpenter, K. G.; Schrijver, C. J.; Karovska, M.; Si Vision Mission Team Bibcode: 2009ASPC..412...91C Altcode: The Stellar Imager (SI) is a UV/Optical, Space-Based Interferometer designed to enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and, via asteroseismology, stellar interiors and of the Universe in general. The ultra-sharp images of the Stellar Imager will revolutionize our view of many dynamic astrophysical processes by transforming point sources into extended sources, and snapshots into evolving views. SI's science focuses on the role of magnetism in the Universe, particularly on magnetic activity on the surfaces of stars like the Sun. SI's prime goal is to enable long-term forecasting of solar activity and the space weather that it drives. SI will also revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. SI is included as a ``Flagship and Landmark Discovery Mission'' in the 2005 NASA Sun Solar System Connection (SSSC) Roadmap and as a candidate for a ``Pathways to Life Observatory'' in the NASA Exploration of the Universe Division (EUD) Roadmap (May, 2005). In this paper we discuss the science goals and technology needs of, and the baseline design for, the SI Mission (http://hires.gsfc.nasa.gov/si/) and its ability to image the Biggest, Baddest, Coolest Stars. Title: Balloon exoplanet nulling interferometer (BENI) Authors: Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Ford, Holland; Petro, Larry; Herman, Jay; Rinehart, Stephen; Carpenter, Kenneth; Marzouk, Joe Bibcode: 2009SPIE.7440E..1AL Altcode: 2009SPIE.7440E..38L We evaluate the feasibility of a balloon-borne nulling interferometer to detect and characterize an exosolar planet and the surrounding debris disk. The existing instrument consists of a three-telescope Fizeau imaging interferometer with thre fast steering mirrors and three delay lines operating at 800 Hz for closed-loop control of wavefront errors and fine pointing. A compact visible nulling interferometer would be coupled to the imaging interferometer and in principle, allows deep starlight suppression. Atmospheric simulations of the environment above 100,000 feet show that balloonborne payloads are a possible path towards the direct detection and characterization of a limited set of exoplanets and debris disks. Furthermore, rapid development of lower cost balloon payloads provide a path towards advancement of NASA technology readiness levels for future space-based exoplanet missions. Discussed are the BENI mission and instrument, the balloon environment and the feasibility of such a balloon-borne mission. Title: Stellar imager (SI): enhancements to the mission enabled by the constellation architecture (Ares I/Ares V) Authors: Carpenter, Kenneth G.; Karovska, Margarita; Lyon, Richard G.; Mozurkewich, D.; Schrijver, Carolus Bibcode: 2009SPIE.7436E..0AC Altcode: 2009SPIE.7436E...9C Stellar Imager (SI) is a space-based, UV/Optical Interferometer (UVOI) with over 200x the resolution of HST. It will enable 0.1 milli-arcsec spectral imaging of stellar surfaces and the Universe in general and open an enormous new "discovery space" for astrophysics with its combination of high angular resolution, dynamic imaging, and spectral energy resolution. SI's goal is to study the role of magnetism in the Universe and revolutionize our understanding of: 1) Solar/Stellar Magnetic Activity and their impact on Space Weather, Planetary Climates, and Life, 2) Magnetic and Accretion Processes and their roles in the Origin & Evolution of Structure and in the Transport of Matter throughout the Universe, 3) the close-in structure of Active Galactic Nuclei and their winds, and 4) Exo-Solar Planet Transits and Disks. SI is a "Landmark/Discovery Mission" in 2005 Heliophysics Roadmap and a candidate UVOI in the 2006 Astrophysics Strategic Plan and is targeted for launch in the mid-2020's. It is a NASA Vision Mission and has been recommended for further study in a 2008 NRC report on missions potentially enabled/enhanced by an Ares V launch. In this paper, we discuss the science goals and required capabilities of SI, the baseline architecture of the mission assuming launch on one or more Delta rockets, and then the potential significant enhancements to the SI science and mission architecture that would be made possible by a launch in the larger volume Ares V payload fairing, and by servicing options under consideration in the Constellation program. Title: Transient Processes in the Atmosphere of α Tau Authors: Airapetian, V.; Carpenter, K. G.; Ake, T. Bibcode: 2009AIPC.1135..215A Altcode: Far Ultraviolet Spectrograph Explorer (FUSE) spectra of UV emission lines observed in α Tau at two epochs separated by four months show dramatic differences in emission line fluxes and line shifts. This presents the first evidence of dynamic plasma heating in the active region of this cool giant star. We discuss these observations in terms of Alfven wave heating in magnetic loops. Title: The Stellar Imager (SI) project: a deep space UV/Optical Interferometer (UVOI) to observe the Universe at 0.1 milli-arcsec angular resolution Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska, Margarita Bibcode: 2009Ap&SS.320..217C Altcode: 2008Ap&SS.tmp...99C The Stellar Imager (SI) is a space-based, UV/Optical Interferometer (UVOI) designed to enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and of the Universe in general. It will also probe via asteroseismology flows and structures in stellar interiors. SI’s science focuses on the role of magnetism in the Universe and will revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes, such as accretion, in the Universe. The ultra-sharp images of SI will revolutionize our view of many dynamic astrophysical processes by transforming point sources into extended sources, and snapshots into evolving views. SI is a “Flagship and Landmark Discovery Mission” in the 2005 Heliophysics Roadmap and a potential implementation of the UVOI in the 2006 Science Program for NASA’s Astronomy and Physics Division. We present here the science goals of the SI Mission, a mission architecture that could meet those goals, and the technology development needed to enable this mission. Additional information on SI can be found at: http://hires.gsfc.nasa.gov/si/ Title: Technology Development for Future Sparse Aperture Telescopes and Interferometers in Space Authors: Carpenter, Kenneth G.; Gendreau, Keith; Leitner, Jesse; Lyon, Richard; Stoneking, Eric; Stahl, H. Philip; Parrish, Joe; Schrijver, Carolus J.; Woodruff, Robert; Lillie, Chuck; Lo, Amy; Mozurkewich, David; Labeyrie, Antoine; Miller, David; Mighell, Ken; Karovska, Margarita; Phillips, James; Allen, Ronald J.; Cash, Webster Bibcode: 2009astro2010T..47C Altcode: No abstract at ADS Title: Luciola hypertelescope space observatory: versatile, upgradable high-resolution imaging, from stars to deep-field cosmology Authors: Labeyrie, Antoine; Le Coroller, Hervé; Dejonghe, Julien; Lardière, Olivier; Aime, Claude; Dohlen, Kjetil; Mourard, Denis; Lyon, Richard; Carpenter, Kenneth G. Bibcode: 2009ExA....23..463L Altcode: 2008ExA...tmp...48L Luciola is a large (1 km) “multi-aperture densified-pupil imaging interferometer”, or “hypertelescope” employing many small apertures, rather than a few large ones, for obtaining direct snapshot images with a high information content. A diluted collector mirror, deployed in space as a flotilla of small mirrors, focuses a sky image which is exploited by several beam-combiner spaceships. Each contains a “pupil densifier” micro-lens array to avoid the diffractive spread and image attenuation caused by the small sub-apertures. The elucidation of hypertelescope imaging properties during the last decade has shown that many small apertures tend to be far more efficient, regarding the science yield, than a few large ones providing a comparable collecting area. For similar underlying physical reasons, radio-astronomy has also evolved in the direction of many-antenna systems such as the proposed Low Frequency Array having “hundreds of thousands of individual receivers”. With its high limiting magnitude, reaching the m v = 30 limit of HST when 100 collectors of 25 cm will match its collecting area, high-resolution direct imaging in multiple channels, broad spectral coverage from the 1,200 Å ultra-violet to the 20 μm infra-red, apodization, coronagraphic and spectroscopic capabilities, the proposed hypertelescope observatory addresses very broad and innovative science covering different areas of ESA’s Cosmic Vision program. In the initial phase, a focal spacecraft covering the UV to near IR spectral range of EMCCD photon-counting cameras (currently 200 to 1,000 nm), will image details on the surface of many stars, as well as their environment, including multiple stars and clusters. Spectra will be obtained for each resel. It will also image neutron star, black-hole and micro-quasar candidates, as well as active galactic nuclei, quasars, gravitational lenses, and other Cosmic Vision targets observable with the initial modest crowding limit. With subsequent upgrade missions, the spectral coverage can be extended from 120 nm to 20 μm, using four detectors carried by two to four focal spacecraft. The number of collector mirrors in the flotilla can also be increased from 12 to 100 and possibly 1,000. The imaging and spectroscopy of habitable exoplanets in the mid infra-red then becomes feasible once the collecting area reaches 6 m2, using a specialized mid infra-red focal spacecraft. Calculations (Boccaletti et al., Icarus 145, 628-636, 2000) have shown that hypertelescope coronagraphy has unequalled sensitivity for detecting, at mid infra-red wavelengths, faint exoplanets within the exo-zodiacal glare. Later upgrades will enable the more difficult imaging and spectroscopy of these faint objects at visible wavelengths, using refined techniques of adaptive coronagraphy (Labeyrie and Le Coroller 2004). Together, the infra-red and visible spectral data carry rich information on the possible presence of life. The close environment of the central black-hole in the Milky Way will be imageable with unprecedented detail in the near infra-red. Cosmological imaging of remote galaxies at the limit of the known universe is also expected, from the ultra-violet to the near infra-red, following the first upgrade, and with greatly increasing sensitivity through successive upgrades. These areas will indeed greatly benefit from the upgrades, in terms of dynamic range, limiting complexity of the objects to be imaged, size of the elementary “Direct Imaging Field”, and limiting magnitude, approaching that of an 8-m space telescope when 1,000 apertures of 25 cm are installed. Similar gains will occur for addressing fundamental problems in physics and cosmology, particularly when observing neutron stars and black holes, single or binary, including the giant black holes, with accretion disks and jets, in active galactic nuclei beyond the Milky Way. Gravitational lensing and micro-lensing patterns, including time-variable patterns and perhaps millisecond lensing flashes which may be beamed by diffraction from sub-stellar masses at sub-parsec distances (Labeyrie, Astron Astrophys 284, 689, 1994), will also be observable initially in the favourable cases, and upgrades will greatly improve the number of observable objects. The observability of gravitational waves emitted by binary lensing masses, in the form of modulated lensing patterns, is a debated issue (Ragazzoni et al., MNRAS 345, 100-110, 2003) but will also become addressable observationally. The technology readiness of Luciola approaches levels where low-orbit testing and stepwise implementation will become feasible in the 2015-2025 time frame. For the following decades beyond 2020, once accurate formation flying techniques will be mastered, much larger hypertelescopes such as the proposed 100 km Exo-Earth Imager and the 100,000 km Neutron Star Imager should also become feasible. Luciola is therefore also seen as a precursor toward such very powerful instruments. Title: Heavy Elements and Cool Stars Authors: Wahlgren, Glenn M.; Carpenter, Kenneth G.; Norris, Ryan P. Bibcode: 2009AIPC.1094..892W Altcode: 2009csss...15..892W We report on progress in the analysis of high-resolution near-IR spectra of α Orionis (M2 Iab) and other cool, luminous stars. Using synthetic spectrum techniques, we search for atomic absorption lines in the stellar spectra and evaluate the available line parameter data for use in our abundance analyses. Our study concentrates on the post iron-group elements copper through zirconium as a means of investigating the slow neutron-capture process of nucleosynthesis in massive stars and the mechanisms that transport recently processed material up into the photospheric region. We discuss problems with the atomic data and model atmospheres that need to be addressed before theoretically derived elemental abundances from pre-supernova nucleosynthesis calculations can be tested by comparison with abundances determined from observations of cool, massive stars. Title: UV, IR, and mm Studies of CO Surrounding the Red Supergiant α Orionis (M2 Iab) Authors: Harper, Graham M.; Carpenter, Kenneth G.; Ryde, Nils; Smith, Nathan; Brown, Joanna; Brown, Alexander; Hinkle, Kenneth H. Bibcode: 2009AIPC.1094..868H Altcode: 2009csss...15..868H Carbon monoxide has been detected in Betelgeuse's ultraviolet (electronic), infrared (vibrational), and mm-radio (rotational) spectra, but its spatial distribution has remained elusive. We have obtained new mm-radio interferometry (CARMA), infrared spatially-resolved spectra (Phoenix/Gemini-South), and we have performed non-LTE simulations to help establish the spatial location of the S1 (V = 10 km/s) and S2 (V = 17 km/s) CO shells. The strong CO Fourth-Positive ultraviolet scattering signature is apparent in the HST GHRS G140L spectrum and the S1 and S2 shells account for much of the UV opacity. Phoenix spectra reveal that the low velocity S1 shell is present at 1.5 arcsec West of the star and extends out to ~4 arcsec, and its mm-radio emission appears to originate within an 6 arcsec radius. The interpretation of the S2 shell is less clear. The Phoenix spectra tentatively suggest that the S2 shell extends to ~7 arcsec. The CARMA channel maps show an additional strong narrow emission component 5 arcsec from the star, but the spectra do not show all the expected S1 and S2 signatures. Future CARMA observations should help to disentangle the signature of the S1 and S2 shells. Title: The Atmospheric Dynamics of α Tau (K5 III)-Clues to Understanding the Magnetic Dynamo in Late-Type Giant Stars Authors: Carpenter, Kenneth G.; Airapetian, Vladimir Bibcode: 2009AIPC.1094..712C Altcode: 2009csss...15..712C Using HST/GHRS, HST/STIS and FUSE archival data for α Tau and the CHIANTI spectroscopic code, we have derived line shifts, volumetric emission measures, and plasma density estimates, and calculated filling factors for a number of UV lines forming between 10,000 K and 300,000 K in the outer atmosphere of this red giant star. The data suggest the presence of low-temperature extended regions and high-temperature compact regions, associated with magnetically open and closed structures in the stellar atmosphere, respectively. The signatures of UV lines from α Tau can be consistently understood via a model of upward-traveling Alfvén waves in a gravitationally stratified atmosphere. These waves cause nonthermal broadening in UV lines due to unresolved wave motions and downward plasma motions in compact magnetic loops heated by resonant Alfvén wave heating. Title: Commission 29: Stellar Spectra Authors: Parthasarathy, Mudumba; Piskunov, Nikolai E.; Sneden, Christopher; Carpenter, Kenneth G.; Castelli, Fiorella; Cunha, Katia; Eenens, Phillippe R. J.; Hubeny, Ivan; Rossi, Silvia; Takada-Hidai, Masahide; Wahlgren, Glenn M.; Weiss, Werner W. Bibcode: 2009IAUTA..27..209P Altcode: The members of IAU Commission 29 Stellar Spectra are actively engaged in the quantitative analysis of spectra of various types of stars. With large and medium size telescopes equipped with high resolution spectrographs LTE and Non-LTE analysis of spectra of all types stars are being carried out. Spectra of stars in our Galaxy, in globular and open clusters, stars in LMC and SMC and in nearby galaxies are being studied. Accurate chemical composition analysis of various types of stars has been carried out during the past three years. Now the analysis of stellar spectra covers the wavelength range from X-ray region to IR and sub-millimeter range. Recently stellar spectra are being analysed using time-dependent, 3D, hydrodynamical model atmospheres to derive accurate stellar abundances. Title: Mass Transport Processes and their Roles in the Formation, Structure, and Evolution of Stars and Stellar Systems Authors: Carpenter, Kenneth G.; Karvovska, Margarita; Schrijver, Carolus J.; Grady, Carol A.; Allen, Ronald J.; Brown, Alexander; Cranmer, Steven R.; Dupree, Andrea K.; Evans, Nancy R.; Guinan, Edward F.; Harper, Graham; Labeyrie, Antoine; Linsky, Jeffrey; Peters, Geraldine J.; Roberge, Aki; Saar, Steven H.; Sonneborn, George; Walter, Frederick M. Bibcode: 2009astro2010S..40C Altcode: 2009arXiv0903.2433C We summarize some of the compelling new scientific opportunities for understanding stars and stellar systems that can be enabled by sub-mas angular resolution, UV/Optical spectral imaging observations, which can reveal the details of the many dynamic processes (e.g., variable magnetic fields, accretion, convection, shocks, pulsations, winds, and jets) that affect their formation, structure, and evolution. These observations can only be provided by long-baseline interferometers or sparse aperture telescopes in space, since the aperture diameters required are in excess of 500 m - a regime in which monolithic or segmented designs are not and will not be feasible - and since they require observations at wavelengths (UV) not accessible from the ground. Two mission concepts which could provide these invaluable observations are NASA's Stellar Imager (SI; http://hires.gsfc.nasa.gov/si/) interferometer and ESA's Luciola sparse aperture hypertelescope, which each could resolve hundreds of stars and stellar systems. These observatories will also open an immense new discovery space for astrophysical research in general and, in particular, for Active Galactic Nuclei (Kraemer et al. Decadal Survey Science Whitepaper). The technology developments needed for these missions are challenging, but eminently feasible (Carpenter et al. Decadal Survey Technology Whitepaper) with a reasonable investment over the next decade to enable flight in the 2025+ timeframe. That investment would enable tremendous gains in our understanding of the individual stars and stellar systems that are the building blocks of our Universe and which serve as the hosts for life throughout the Cosmos. Title: Active Galactic Nuclei and their role in Galaxy Formation and Evolution Authors: Kraemer, Steve; Windhorst, Rogier; Carpenter, Kenneth G.; Crenshaw, Mike; Elvis, Martin; Karovska, Margarita Bibcode: 2009astro2010S.162K Altcode: 2009arXiv0904.3875K There are several key open questions as to the nature and origin of AGN including: 1) what initiates the active phase, 2) the duration of the active phase, and 3) the effect of the AGN on the host galaxy. Critical new insights to these can be achieved by probing the central regions of AGN with sub-mas angular resolution at UV/optical wavelengths. In particular, such observations would enable us to constrain the energetics of the AGN "feedback" mechanism, which is critical for understanding the role of AGN in galaxy formation and evolution. These observations can only be obtained by long-baseline interferometers or sparse aperture telescopes in space, since the aperture diameters required are in excess of 500 m - a regime in which monolithic or segmented designs are not and will not be feasible and because these observations require the detection of faint emission near the bright unresolved continuum source, which is impossible from the ground, even with adaptive optics. Two mission concepts which could provide these invaluable observations are NASA's Stellar Imager (SI; Carpenter et al. 2008 & http://hires.gsfc.nasa.gov/si/) interferometer and ESA's Luciola (Labeyrie 2008) sparse aperture hypertelescope. Title: Stellar Imager (SI) - Observing the Universe in High Definition Authors: Carpenter, Kenneth G.; Karovska, M.; Schrijver, C. J.; SI Development Team Bibcode: 2009AAS...21345113C Altcode: 2009BAAS...41..346C Stellar Imager (http://hires.gsfc.nasa.gov/si/) is a space-based, UV/Optical Interferometer (UVOI) with over 200x HST's resolution. It will enable 0.1 milli-arcsec spectral imaging of stellar surfaces and the Universe in general and open an enormous new "discovery space" for Astrophysics with its combination of high angular resolution, dynamic imaging, and spectral energy resolution. SI's goal is to study the role of magnetism in the Universe and revolutionize our understanding of: 1) Solar/Stellar Magnetic Activity and their impact on Space Weather, Planetary Climates, and Life, 2) Magnetic and Accretion Processes and their roles in the Origin and Evolution of Structure and in the Transport of Matter throughout the Universe, 3) the close-in structure of Active Galactic Nuclei, and 4) Exo-Solar Planet Transits and Disks. The SI mission is targeted for the mid 2020's - thus significant technology development in the upcoming decade is critical to enabling it and future space-based sparse aperture telescope and distributed spacecraft missions. The key technology needs include: 1) precision formation flying of many spacecraft, 2) precision metrology over km-scales, 3) closed-loop control of many-element, sparse optical arrays, 4) staged-control systems with very high dynamic ranges (nm to km-scale). It is critical that the importance of timely development of these capabilities is called out in the upcoming Astrophysics and Heliophysics Decadal Surveys, to enable the flight of such missions in the following decade. SI is a "Landmark/Discovery Mission" in the 2005 Heliophysics Roadmap and a candidate UVOI in the 2006 Astrophysics Strategic Plan. It is a NASA Vision Mission ("NASA Space Science Vision Missions" (2008), ed. M. Allen) and has also been recommended for further study in the 2008 NRC interim report on missions potentially enabled or enhanced by an Ares V launch, although an incrementally-deployed version could be launched using smaller rockets. Title: Exoplanet Characterization and the Search for Life Authors: Kasting, James; Traub, W.; Roberge, A.; Leger, A.; Schwartz, A.; Wootten, A.; Vosteen, A.; Lo, A.; Brack, A.; Tanner, A.; Coustenis, A.; Lane, B.; Oppenheimer, B.; Mennesson, B.; Lopez, B.; Grillmair, C.; Beichman, C.; Cockell, C.; Hanot, C.; McCarthy, C.; Stark, C.; Marois, C.; Aime, C.; Angerhausen, D.; Montes, D.; Wilner, D.; Defrere, D.; Mourard, D.; Lin, D.; Kite, E.; Chassefiere, E.; Malbet, F.; Tian, F.; Westall, F.; Illingworth, G.; Vasisht, G.; Serabyn, G.; Marcy, G.; Bryden, G.; White, G.; Laughlin, G.; Torres, G.; Hammel, H.; Ferguson, H.; Shibai, H.; Rottgering, H.; Surdej, J.; Wiseman, J.; Ge, J.; Bally, J.; Krist, J.; Monnier, J.; Trauger, J.; Horner, J.; Catanzarite, J.; Harrington, J.; Nishikawa, J.; Stapelfeldt, K.; von Braun, K.; Biazzo, K.; Carpenter, K.; Balasubramanian, K.; Kaltenegger, L.; Postman, M.; Spaans, M.; Turnbull, M.; Levine, M.; Burchell, M.; Ealey, M.; Kuchner, M.; Marley, M.; Dominik, M.; Mountain, M.; Kenworthy, M.; Muterspaugh, M.; Shao, M.; Zhao, M.; Tamura, M.; Kasdin, N.; Haghighipour, N.; Kiang, N.; Elias, N.; Woolf, N.; Mason, N.; Absil, O.; Guyon, O.; Lay, O.; Borde, P.; Fouque, P.; Kalas, P.; Lowrance, P.; Plavchan, P.; Hinz, P.; Kervella, P.; Chen, P.; Akeson, R.; Soummer, R.; Waters, R.; Barry, R.; Kendrick, R.; Brown, R.; Vanderbei, R.; Woodruff, R.; Danner, R.; Allen, R.; Polidan, R.; Seager, S.; MacPhee, S.; Hosseini, S.; Metchev, S.; Kafka, S.; Ridgway, S.; Rinehart, S.; Unwin, S.; Shaklan, S.; ten Brummelaar, T.; Mazeh, T.; Meadows, V.; Weiss, W.; Danchi, W.; Ip, W.; Rabbia, Y. Bibcode: 2009astro2010S.151K Altcode: 2009arXiv0911.2936K Over 300 extrasolar planets (exoplanets) have been detected orbiting nearby stars. We now hope to conduct a census of all planets around nearby stars and to characterize their atmospheres and surfaces with spectroscopy. Rocky planets within their star's habitable zones have the highest priority, as these have the potential to harbor life. Our science goal is to find and characterize all nearby exoplanets; this requires that we measure the mass, orbit, and spectroscopic signature of each one at visible and infrared wavelengths. The techniques for doing this are at hand today. Within the decade we could answer long-standing questions about the evolution and nature of other planetary systems, and we could search for clues as to whether life exists elsewhere in our galactic neighborhood. Title: Stellar Imager: wavefront control Authors: Lyon, Richard G.; Carpenter, Kenneth G.; Petrone, Peter; Dogoda, Peter; Reed, Daniel; Mozurkewich, David Bibcode: 2008SPIE.7011E..31L Altcode: 2008SPIE.7011E..89L Stellar Imager (SI) is a proposed NASA space-based UV imaging interferometer to resolve the stellar disks of nearby stars. SI would consist of 20 - 30 separate spacecraft flying in formation at the Earth-Sun L2 libration point. Onboard wavefront sensing and control is required to maintain alignment during science observations and after array reconfigurations. The Fizeau Interferometry Testbed (FIT), developed at the NASA/Goddard Space Flight Center, is being used to study wavefront sensing and control methodologies for Stellar Imager and other large, sparse aperture telescope systems. FIT initially consists of 7 articulated spherical mirrors in a Golay pattern, and is currently undergoing expansion to 18 elements. FIT currently uses in-focus whitelight sparse aperture PSFs and a direct solve broadband phase retrieval algorithm to sense and control its wavefront. Ultimately it will use extended scene wavelength, with a sequential diversity algorithm that modulates a subset of aperture pistons to jointly estimate the wavefront and the reconstructed image from extended scenes. The recovered wavefront is decomposed into the eigenmodes of the control matrix and actuators are moved to minimize the wavefront piston, tip and tilt in closed-loop. We discuss the testbed, wavefront control methodology and ongoing work to increase its bandwidth from 1 per 11 seconds to a few 10's of Hertz and show ongoing results. Title: Atmospheric Dynamics in α Tau Authors: Airapetian, Vladimir; Carpenter, K. G. Bibcode: 2008AAS...21116215A Altcode: HST/GHRS, HST/STIS and FUSE observations of evolved late-type stars demonstrated the presence of non-thermally broadened UV emission lines forming at temperatures of 10,000 to 300,000K in almost all of the stars. In this study we analyze CI 1993.62A, CII] 2323.5A, SiIII 2350.17A, SiIV 1393A, CIII 977A, OIV 1401.35A and OVI 1032A emission lines from Tau. Our analysis of these UV lines reveal redshifts T (except for OVI 1032A), while non-thermal velocities T . Derived emission measures indicate filling factors <0.1%. These findings force us to reconsider the definition of chromospheric and transition regions in these stars as patchy regions or atmospheric hot spots. According to Freytag et al. (2002), convective cells with sizes of 0.01Rstar generate shock waves that dissipate at lower atmospheric layers. Large-scale convective motions produce large-scale magnetic structures in contrast to arcades of thin solar-like loops powered by small-scale granular motions. We discuss the model of non-linear Alfven waves amplified by resonant interaction with sound waves and propagating upward along one (or a few) constant pressure large-scale loop(s). As Alfven waves propagate upward in a gravitationally stratified atmosphere, their wave amplitudes increase causing non-thermal broadening in UV lines due to unresolved wave motions. We discuss a model that predicts downward plasma motions in extended loops driven by asymmetric Alfven wave heating. We use a state-of-the-art 2.5 MHD code to show that the energy flux density of Alfven waves (with P a few days), which are needed to explain the radiative cooling and non-thermal broadening in the UV lines, is consistent with the requirement to drive massive ( 10 MSun/yr) and slow ( 30 km/s) stellar winds from magnetically open structures with the assumption of a magnetic field at the wind base 1 G.

This research is supported by the NASA Research grant to CUA from GSFC No. NASA-NNG06GJ29G Title: The Stellar Imager Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska, Margarita Bibcode: 2008nssv.book..191C Altcode: No abstract at ADS Title: Towards a Small Prototype Planet Finding Interferometer: The next step in planet finding and characterization in the infrared Authors: Danchi, W. C.; Deming, D.; Carpenter, K. G.; Barry, R. K.; Hinz, P.; Johnston, K. J.; Lawson, P.; Lay, O.; Monnier, J. D.; Richardson, L. J.; Rinehart, S.; Traub, W. Bibcode: 2008arXiv0801.4752D Altcode: During the last few years, considerable effort has been directed towards large-scale (>> $1 Billion US) missions to detect and characterize earth-like planets around nearby stars, such as the Terrestrial Planet Finder Interferometer (TPF-I) and Darwin missions. However, technological and budgetary issues as well as shifting science priorities will likely prevent these missions from entering Phase A until the next decade. The secondary eclipse technique using the Spitzer Space Telescope has been used to directly measure the temperature and emission spectrum of extrasolar planets. However, only a small fraction of known extrasolar planets are in transiting orbits. Thus, a simplified nulling interferometer, which produces an artificial eclipse or occultation, and operates in the near- to mid-infrared (e.g. ~ 3 to 8 or 10 microns), can characterize the atmospheres of this much larger sample of the known but non-transiting exoplanets. Many other scientific problems can be addressed with a system like this, including imaging debris disks, active galactic nuclei, and low mass companions around nearby stars. We discuss the rationale for a probe-scale mission in the $600-800 Million range, which we name here as the Small Prototype Planet Finding Interferometer (SPPFI). Title: Wavefront sensing and closed-loop control for the Fizeau interferometry testbed Authors: Lyon, Richard G.; Carpenter, Kenneth G.; Liu, Alice; Petrone, Peter; Dogoda, Peter; Reed, Daniel; Mozurkewich, David Bibcode: 2007SPIE.6687E..0HL Altcode: Stellar Imager (SI) is a proposed NASA space-based UV imaging interferometer to resolve the stellar disks of nearby stars. SI would consist of 20 - 30 separate spacecraft flying in formation at the Earth-Sun L2 libration point. Onboard wavefront sensing and control is required to maintain alignment during science observations and after array reconfigurations. The Fizeau Interferometry Testbed (FIT), developed at the NASA/Goddard Space Flight Center, is being used to study wavefront sensing and control methodologies for Stellar Imager and other large, sparse aperture telescope systems. FIT initially consists of 7 articulated spherical mirrors in a Golay pattern, and is currently undergoing expansion to 18 elements. FIT currently uses in-focus whitelight sparse aperture PSFs and a direct solve phase retrieval algorithm to sense and control its wavefront. Ultimately it will use extended scene wavelength, with a sequential diversity algorithm that modulates a subset of aperture pistons to jointly estimate the wavefront and the reconstructed image from extended scenes. The recovered wavefront is decomposed into the eigenmodes of the control matrix and actuators are moved to minimize the wavefront piston, tip and tilt in closed-loop. We discuss the testbed, wavefront control methodology and ongoing work to increase its bandwidth from 1 per 11 seconds to a few 10's of Hertz and show ongoing results. Title: Beam combination for Stellar Imager and its application to full-aperture imaging Authors: Mozurkewich, D.; Carpenter, K. G.; Lyon, R. G. Bibcode: 2007SPIE.6687E..0KM Altcode: 2007SPIE.6687E..19M Stellar Imager (SI) will be a Space-Based telescope consisting of 20 to 30 separated apertures. It is designed for UV/Optical imaging of stellar surfaces and asteroseismology. This report describes details of an alternative optical design for the beam combiner, dubbed the Spatial Frequency Remapper (SFR). It sacrifices the large field of view of the Fizeau combiner. In return, spectral resolution is obtained with a diffraction grating rather than an array of energy-resolving detectors. The SFR design works in principle and has been implemented with MIRC at CHARA for a small number of apertures. Here, we show the number of optical surfaces can be reduced and the concept scales gracefully to the large number of apertures needed for Stellar Imager. We also describe a potential application of this spatial frequency remapping to improved imaging with filled-aperture systems. For filled-aperture imaging, the SFR becomes the core of an improved aperture masking system. To date, aperture-masking has produced the best images with ground-based telescopes but at the expense of low sensitivity due to short exposures and the discarding of most of the light collected by the telescope. This design eliminates the light-loss problem previously claimed to be inherent in all aperture-masking designs. We also argue that at least in principle, the short-integration time limit can also be overcome. With these improvements, it becomes an ideal camera for TPF-C; since it can form speckle-free images in the presence of wavefront errors, it should significantly relax the stability requirements of the current designs. Title: Direct UV/optical imaging of stellar surfaces: the Stellar Imager Vision Mission Authors: Carpenter, Kenneth G.; Lyon, Richard G.; Schrijver, Carolus; Karovska, Margarita; Mozurkewich, David Bibcode: 2007SPIE.6687E..0GC Altcode: 2007SPIE.6687E..15C The Stellar Imager (SI) is a UV/optical, space-based interferometer designed to enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and, via asteroseismology, stellar interiors and of the Universe in general. SI's science focuses on the role of magnetism in the Universe, particularly on magnetic activity on the surfaces of stars like the Sun. SI's prime goal is to enable long-term forecasting of solar activity and the space weather that it drives, in support of the Living with a Star program in the Exploration Era. SI will also revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. SI is a "Flagship and Landmark Discovery Mission" in the 2005 Sun Solar System Connection (SSSC) Roadmap and a candidate for a "Pathways to Life Observatory" in the Exploration of the Universe Division (EUD) Roadmap (May, 2005). We discuss herein the science goals of the SI Mission, a mission architecture that could meet those goals, and the technologies needed to enable this mission. Additional information on SI can be found at: http://hires.gsfc.nasa.gov/si/. Title: Dynamos, Asteroseismology, and the Stellar Imager Authors: Schrijver, C. J.; Carpenter, K. G.; Karovska, M. Bibcode: 2007CoAst.150..364S Altcode: The ultra-sharp images of the Stellar Imager (SI) will revolutionize our view of many dynamic astrophysical processes: The 0.1 milli-arcsec resolution of this deep-space telescope will transform point sources into extended sources, and simple snapshots into spellbinding evolving views. SI's science focuses on the role of magnetism in the Universe, particularly on magnetic activity on the surfaces of stars like the Sun and on the subsurface flows that drive this activity. SI's prime goal is to image magnetically active stars with enough resolution to map their evolving dynamo patterns and their internal flows. By exploring the Universe at ultra-high resolution, SI will also revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of Earth as well as distant exoplanets, and of many magneto-hydrodynamically controlled structures and processes in the Universe.

See http://hires.gsfc.nasa.gov/si/ for details on the Stellar Imager mission. Title: Stellar Imager Authors: Carpenter, Kenneth Bibcode: 2007STIN...0734890C Altcode: The Stellar Imager (SI) is one of NASA's "Vision Missions" - concepts for future, space-based, strategic missions that could enormously increase our capabilities for observing the Cosmos. SI is designed as a UV/Optical Interferometer which will enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and, via asteroseismology, stellar interiors and of the Universe in general. The ultra-sharp images of the Stellar Imager will revolutionize our view of many dynamic astrophysical processes by transforming point sources into extended sources, and snapshots into evolving views. SI, with a characteristic angular resolution of 0.1 milli-arcseconds at 2000 Angstroms, represents an advance in image detail of several hundred times over that provided by the Hubble Space Telescope. The Stellar Imager will zoom in on what today-with few exceptions - we only know as point sources, revealing processes never before seen, thus providing a tool as fundamental to astrophysics as the microscope is to the study of life on Earth. SI's science focuses on the role of magnetism in the Universe, particularly on magnetic activity on the surfaces of stars like the Sun. It's prime goal is to enable long-term forecasting of solar activity and the space weather that it drives, in support of the Living With a Star program in the Exploration Era. SI will also revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. Stellar Imager is included as a "Flagship and Landmark Discovery Mission" in the 2005 Sun Solar System Connection (SSSC) Roadmap and as a candidate for a "Pathways to Life Observatory" in the Exploration of the Universe Division (EUD) Roadmap (May, 2005) and as such is a candidate mission for the 2025-2030 timeframe. An artist's drawing of the current "baseline" concept for SI is presented. Title: Steps Toward a UV/Optical Interferometer in Space: FIT & SIFFT Authors: Carpenter, Kenneth G.; Lyon, R. G.; Liu, A.; Dogoda, P.; Petrone, P.; Mozurkewich, D.; Miller, D.; Mohan, S.; Stahl, P. Bibcode: 2006AAS...20916401C Altcode: 2006BAAS...38R1129C We summarize the goals and result-to-date of a ROSES/APRA-sponsored program to develop two of the major technologies needed to enable the design and construction of future large baseline, space-based Interferometric and Sparse Aperture Telescope missions (e.g., Stellar Imager, Life Finder, Black Hole Imager, and Planet Imager). The Fizeau Interferometer Testbed (FIT) is being used to develop and demonstrate nm-level, closed-loop optical control of mirrors (i.e., control of tip, tilt, piston, translation of array elements) and the overall system to keep multiple beams in phase and optimize imaging of a Fizeau interferometric system and to assess various image reconstruction algorithms (phase diversity, clean, maximum entropy method, etc.) for utility and accuracy. The Synthetic Imaging Formation Flying Testbed (SIFFT) is, in parallel, being used to develop and demonstrate algorithms for autonomous cm-level precision formation flying, which can be combined in the future with the higher precision optical control systems (e.g., those developed on the FIT) to fully enable synthetic aperture imaging systems. The ultimate goal of this research is the demonstration of closed-loop performance of a unified system which combines formation flying and nm-level optical control systems (based on analysis of the science data stream) to maintain phasing of a large array of space-borne mirrors, as needed for missions like those listed above, as well as smaller baseline Precursor missions that may pave the path to the larger strategic missions. Title: Heavy Element Abundances in the Photospheres of Cool Supergiants Authors: Wahlgren, Glenn M.; Lundqvist, M.; Carpenter, K. G. Bibcode: 2006AAS...209.9304W Altcode: 2006BAAS...38.1030W We report on a program to determine the chemical composition of massive, cool supergiant photospheres. We concentrate on elements heavier than the iron group, addressing the question of whether nuclear by-products from the weak s-process have been brought to the surface by convective processes. For massive stars, atoms with mass up to approximately A = 100 are thought to be formed by neutron capture via the weak s-process. The abundances of these elements have been calculated by other researchers to be a function of stellar mass.

Our initial work has concentrated on the identification of useful atomic spectral lines at infrared wavelengths, where absorption from molecular species is reduced relative to that at optical wavelengths for M-type stars. Abundances are determined by synthetic spectrum fitting to line profiles in high-resolution spectra.

We present results for the cool, supergiant Betelgeuse (M2 Iab). Abundances are determined for a number of heavy elements, and despite large uncertainties attributed to the available atomic data (oscillator strengths), a distinct enhancement of Sr is determined after correcting for non-LTE effects. Such an enhancement is predicted by models of interior nucleosynthesis via neutron capture. Our results illuminate the problems that must be overcome before being able to derive abundances with the accuracy required for rigorous comparison with theoretical calculations. We also present our approach to applying the results for Betelgeuse to additional cool supergiants. Title: The Stellar Imager (SI) vision mission Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska, Margarita Bibcode: 2006SPIE.6268E..21C Altcode: 2006astro.ph..6411C; 2006SPIE.6268E..63C The Stellar Imager (SI) is a UV-Optical, Space-Based Interferometer designed to enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and of the Universe in general and asteroseismic imaging of stellar interiors. SI is identified as a "Flagship and Landmark Discovery Mission" in the 2005 Sun Solar System Connection (SSSC) Roadmap and as a candidate for a "Pathways to Life Observatory" in the Exploration of the Universe Division (EUD) Roadmap (May, 2005). SI will revolutionize our view of many dynamic astrophysical processes: its resolution will transform point sources into extended sources, and snapshots into evolving views. SI's science focuses on the role of magnetism in the Universe, particularly on magnetic activity on the surfaces of stars like the Sun. SI's prime goal is to enable long-term forecasting of solar activity and the space weather that it drives. SI will also revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. The results of the SI "Vision Mission" Study are presented in this paper. Additional information on the SI mission concept and related technology development can be found at URL: http://hires.gsfc.nasa.gov/si/. Title: SI - The Stellar Imager: Results from the Vision Mission Study Authors: Carpenter, K. G.; Schrijver, C. J.; Karovska, M.; SI Vision Mission Study Team Bibcode: 2005AAS...207.2307C Altcode: 2005BAAS...37R1196C The Stellar Imager (SI) is a UV-Optical, Space-Based Interferometer designed to enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and stellar interiors (via asteroseismology) and of the Universe in general. SI was included as a "far horizon" or "Vision Mission" in the 2000 and 2003 SEC Roadmaps and is now identified as a "Flagship and Landmark Discovery Mission" in the 2005 Sun Solar System Connection (SSSC) Roadmap and as a candidate for a "Pathways to Life Observatory" in the Exploration of the Universe Division (EUD) Roadmap (May, 2005). The ultra-sharp images of the Stellar Imager will revolutionize our view of many dynamic astrophysical processes: The 0.1 mas resolution of this deep-space telescope will transform point sources into extended sources, and snapshots into evolving views. SI's science focuses on the role of magnetism in the Universe, particularly on magnetic activity on the surfaces of stars like the Sun. SI's prime goal is to enable long-term forecasting of solar activity and the space weather that it drives in support of the Living With a Star program in the Exploration Era. SI will also revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. The results of a just-concluded "Vision Mission" Study of Stellar Imager will be presented in this paper.

This work was supported, in part, by Vision Mission Study grants from NASA HQ to NASA-GSFC and from GSFC to Smithsonian Astrophysical Observatory, Seabrook Engineering, SUNY/Stonybrook, U. Colorado/Boulder, and STScI. Substantial complementary internal institutional support is gratefully acknowledged from all of the participating institutions. Title: High-Mass Triple Systems: The Classical Cepheid Y Carinae Authors: Evans, Nancy Remage; Carpenter, Kenneth G.; Robinson, Richard; Kienzle, Francesco; Dekas, Anne E. Bibcode: 2005AJ....130..789E Altcode: 2005astro.ph..4169E We have obtained a Hubble Space Telescope STIS ultraviolet high-dispersion echelle-mode spectrum of the binary companion of the double-mode classical Cepheid Y Car. The velocity measured for the hot companion from this spectrum is very different from reasonable predictions for binary motion, implying that the companion is itself a short-period binary. The measured velocity changed by 7 km s-1 during the 4 days between two segments of the observation, confirming this interpretation. We summarize ``binary'' Cepheids that are in fact members of a triple system and find that at least 44% are triples. The summary of information on Cepheids with orbits makes it likely that the fraction is underestimated.

Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. Title: The Stellar Imager: a deep-space telescope to image stellar surfaces Authors: Schrijver, C. J.; Carpenter, K. G.; Karovska, M.; Si Vision Mission Team Bibcode: 2005ESASP.560..951S Altcode: 2005csss...13..951S No abstract at ADS Title: Planetary Environment Study at Sub-milliarcsecond Resolution Authors: Ragozzine, D.; Karovska, M.; Hartmann, L.; Sasselov, D.; Carpenter, K.; SI Team Bibcode: 2004AAS...205.1718R Altcode: 2004BAAS...36.1368R The Stellar Imager (SI; http://hires.gsfc.nasa.gov/ ∼si ) is a NASA Vision Mission, conceived of as a space-based UV-Optical long-baseline interferometer that will provide sub-milliarcsecond imaging capabilities. We present results from our study of how SI could be used to answer key questions about planet formation and planet-star-disk interactions. SI would be able to resolve and characterize star-disk interactions at a few stellar radii, including accretion and inner disk edge heating. Simple models of T-Tauri stars are used to probe SI's sensitivity to various critical parameters and geometries. By observing H2-flourescent lines in the UV, the contrast between the luminosity of the star and the gas can be improved. A list of potential targets among known planet-harboring stars is also presented with the hope of resolving possible star-planet interactions.

Acknowledgement: This work was supported by the SI Vision Mission study grant NNG04GM92G from NASA/GSFC to SAO. MK is a member of the Chandra X-ray Center (NASA contract NAS8-39073). Title: Stellar Imager (SI) Vision Mission Science Drivers Authors: Karovska, M.; Carpenter, K. G.; Schrijver, C. J.; SI Mission Concept Development Bibcode: 2004AAS...20518005K Altcode: 2005BAAS...37..384K We describe the key scientific drivers for the Stellar Imager (SI) Vision Mission - a UV-optical 0.1 milli-arcsecond (mas) imaging space interferometer. Ultra-high sub-mas angular resolution imaging at UV and optical wavelengths is key to studies of magnetic field structures that govern the formation of stars and planetary systems, the habitability of planets, long-term space weather in the Exploration era, and transport processes on many scales in the Universe. Magnetic fields affect the evolution of structure in the Universe and drive solar and stellar activity which is a key to life's origin and survival. However, our understanding of how magnetic fields form, operate, and evolve is currently very limited, even for the nearest star, our Sun.

The key science goal of the Stellar Imager Mission is to obtain an understanding of stellar dynamos, and in particular the solar dynamo, through a population study of other stars representing a broad range of stellar parameters and activity. The end goal is to understand the variable impact of stellar magnetic activity on planetary climates and the origin and maintenance of life. Improved knowledge of solar-type dynamo activity and the interaction of global fields and flows is also crucial for developing models for long-term space weather forcasting. Furthermore, SI's high-angular resolution capabilities, over two magnitudes better then the HST, will enable unprecedented studies of dynamo and accretion-driven processes, and mass exchange and mass flows in a wide variety of galactic and extragalactic sources, including young star/disk systems, solar-type and evolved stars and astrospheres, numerous interacting binaries, and SN, AGN, and black hole environments. Title: The Stellar Imager (SI): Preliminary Results from the Ongoing Vision Mission Study Authors: Carpenter, K. G.; Schrijver, C. J.; SI Mission Concept Development Team Bibcode: 2004AAS...205.0509C Altcode: 2004BAAS...36.1342C; 2004AAS...205..509C The Stellar Imager (SI) is a "Vision Mission" in the far-horizon NASA Roadmap, conceived for the purpose of understanding the effects of stellar magnetic fields, the dynamos that generate them, and the internal structure and dynamics of the stars in which they exist. The ultimate goal is to achieve the best possible forecasting of solar/stellar activity and to understand the impact of that activity on planetary climates and the origin and maintenance of life in the Universe. The science goals of SI require an ultra-high angular resolution, at ultraviolet wavelengths, on the order of 100 micro-arcsec and baselines on the order of 0.5 km. SI's resolution will make it an invaluable resource for many other areas of astrophysics, including studies of AGN's, supernovae, cataclysmic variables, young stellar objects, QSO's, and stellar black holes. These requirements call for a large, multi-spacecraft (>20) imaging interferometer, utilizing precision formation flying in a stable environment, such as in a Lissajous orbit around the Sun-Earth L2 point. In this paper, we present an update on the ongoing SI Vision Mission concept and technology development studies.

The SI Mission Concept Study is supported, in part, by grants from NASA-HQ through the 2003 Vision Mission NRA. Title: Apodized square aperture plus occulter concept for TPF Authors: Jordan, Ian J. E.; Schultz, Alfred B.; Lyon, Richard G.; Hart, Helen M.; Bruhweiler, Frederick; Fraquelli, Dorothy A.; Carpenter, Kenneth G.; Kochte, Mark; Hollis, Jan M. Bibcode: 2004SPIE.5487.1391J Altcode: The standard approach to achieving TPF-level starlight suppression has been to couple a few techniques together. Deployment of a low- or medium-performance external occulter as the first stage of starlight suppression reduces manufacturing challenges, mitigates under-performance risks, lowers development costs, and hastens launch date for TPF. This paper describes the important aspects of a conceptual 4-metre apodized square aperture telescope system utilizing a low-performance external occulter. Adding an external occulter to such a standard TPF design provides a benefit that no other technique offers: scattered and diffracted on-axis starlight is suppressed by orders of magnitude before reaching the telescope. This translates directly into relaxed requirements on the remainder of the optical system. Title: Metrology and pointing for astronomical interferometers Authors: Phillips, James D.; Carpenter, Kenneth G.; Gendreau, Keith C.; Karovska, Margarita; Kaaret, Philip E.; Reasenberg, Robert D. Bibcode: 2004SPIE.5491..320P Altcode: Metrology and pointing will be enabling technologies for a new generation of astronomical missions having large and distributed apertures and delivering unprecedented performance. The UV interferometer Stellar Imager would study stellar dynamos by imaging magnetic activity on the disks of stars in our Galaxy. The X-ray interferometer Black Hole Imager would study strong gravity physics and the formation of jets by imaging the event horizons of supermassive black holes. These missions require pointing to microarcseconds or better, and metrology to nm accuracy of optical elements separated by km, for control of optical path difference. This paper describes a metrology and pointing system that meets these requirements for the Stellar Imager. A reference platform uses interferometers to sense alignment with a guide star. Laser gauges determine mirror positions in the frame of the reference platform, and detector position is monitored by laser gauges or observations of an artificial star. Applications to other astronomical instruments are discussed. Title: The Fizeau interferometer testbed (FIT): developing and testing the technologies needed for space-based interferometric imaging systems Authors: Mazzuca, Lisa M.; Carpenter, Kenneth G.; Lyon, Richard G.; Marzouk, Joe; Petrone, Peter, III; Cottle, Paul; Dogoda, Peter; Huet, Hubert; Liiva, Peter; Mozurkewich, David; Armstrong, J. T.; Zhang, Xiaolei; Solyar, Gregory; Mundy, Lee G. Bibcode: 2004SPIE.5491.1034M Altcode: The Fizeau Interferometer Testbed (FIT) is a ground-based laboratory experiment at Goddard Space Flight Center (GSFC) designed to develop and test technologies that will be needed for future interferometric spacecraft missions. Specifically, the research from this experiment is a proof-of-concept for optical accuracy and stability, closed-loop control algorithms, optimal sampling methodology of the Fourier UV-plane, computational models for system performance, and image synthesis techniques for a sparse array of 7 to 30 mirrors. It will assess and refine the technical requirements on hardware, control, and imaging algorithms for the Stellar Imager (SI), its pathfinder mission, and other sparse aperture and interferometric imaging mission concepts. This ground-based optical system is a collaborative effort between NASA's GSFC, Sigma Space Corporation, the Naval Research Laboratory, and the University of Maryland. We present an overview of the FIT design goals and explain their associated validation methods. We further document the design requirements and provide a status on their completion. Next, we show the overall FIT design, including the optics and data acquisition process. We discuss the technologies needed to insure success of the testbed as well as for an entire class of future mission concepts. Finally, we compare the expected performance to the actual performance of the testbed using the initial array of seven spherical mirrors. Currently, we have aligned and phased all seven mirrors, demonstrated excellent system stability for extended periods of time, and begun open-loop operations using "pinhole" light sources. Extended scenes and calibration masks are being fabricated and will shortly be installed in the source module. Installation of all the different phase retrieval/diversity algorithms and control software is well on the way to completion, in preparation for future tests of closed-loop operations. Title: Fizeau interferometry testbed: wavefront control Authors: Lyon, Richard G.; Carpenter, Kenneth G.; Mazzuca, Lisa; Huet, Hubert; Cottle, Paul W.; Petrone, Peter P., III; Dagoda, Peter; Liiva, Peter; Marzouk, Joe; Solyar, Gregory; Mozurkewich, David; Zhang, Xiaolei; Armstrong, Thomas Bibcode: 2004SPIE.5487..963L Altcode: Stellar Imager (SI) is a potential NASA space-based UV imaging interferometer to resolve the stellar disks of nearby stars. SI would consist of 20 - 30 separate spacecraft flying in formation at the Earth-Sun L2 libration point. Onboard wavefront control would be required to initially align the formation and maintain alignment during science observations and after array reconfiguration. The Fizeau Interferometry Testbed (FIT) is a testbed currently under development at the NASA/Goddard Space Flight Center to develop and study the wavefront control methodologies for Stellar Imager and other large, sparse aperture telescope systems. FIT consists of 7 articulated spherical mirrors in a Golay pattern, expandable up to 30 elements, and reconfigurable into multiple array patterns. FIT"s purpose is to demonstrate image quality versus array configuration and to develop and advance the wavefront control for SI. FIT uses extended scene wavelength, focus and field diversity to estimate the wavefront across the set of apertures. The recovered wavefront is decomposed into the eigenmodes of the control matrix and actuators are moved to minimize the wavefront piston, tip and tilt. Each mirror"s actuators are 3 degrees of freedom, however, they do not move each of the mirrors about a point on each mirrors surface, thus the mapping from wavefront piston, tip/tilt to mirror piston, tip/tilt is not diagonal. We initially estimate this mapping but update it as part of wavefront sensing and control process using system identification techniques. We discuss the FIT testbed, wavefront control methodology, and show initial results from FIT. Title: Fabrication and characterization of the Fizeau interferometer testbed Authors: Petrone, Peter, III; Carpenter, Kenneth G.; Clark, Dave; Cottle, Paul; Dogoda, Peter; Huet, Hubert; Liiva, Peter; Lyon, Richard G.; Marzouk, Joe; Mazzuca, Lisa M.; McAndrew, Dave; Solyar, Gregory Bibcode: 2004SPIE.5491.1776P Altcode: The Fizeau Interferometer Testbed (FIT) is a ground-based system that will be used for the development and testing of technologies relevant to Stellar Imager (SI) and other sparse aperture/Fizeau imaging interferometer mission concepts. The testbed will utilize image-based wavefront sensing and control to co-phase and maintain closed-loop control over a Sparse Aperture Array (SAA) consisting of spherical mirror elements. The SAA is a re-configurable assembly baselined to incorporate between seven (initially) and thirty 12.5mm diameter (R = 4000mm) mirror elements. In this paper we describe the fabrication, alignment, and initial calibration of the phase I (7 primary elements) FIT hardware and discuss various factors impacting the performance and stability of the testbed. Title: The Stellar Imager (SI): a revolutionary large-baseline imaging interferometer at the Sun-Earth L2 point Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Allen, Ronald J.; Brown, Alexander; Chenette, David; Danchi, William C.; Karovska, Margarita; Kilston, Steven; Lyon, Richard G.; Marzouk, Joe; Mazzuca, Lisa M.; Moe, Rud V.; Walter, Frederick; Murphy, Neil Bibcode: 2004SPIE.5491..243C Altcode: The Stellar Imager (SI) is a far-horizon or "Vision" mission in the NASA Sun-Earth Connection (SEC) Roadmap, conceived for the purpose of understanding the effects of stellar magnetic fields, the dynamos that generate them, and the internal structure and dynamics of the stars in which they exist. The ultimate goal is to achieve the best possible forecasting of solar/stellar activity and its impact on life in the Universe. The science goals of SI require an ultra-high angular resolution, at ultraviolet wavelengths, on the order of 0.1 milliarcsec and thus baselines on the order of 500 meters. These requirements call for a large, multi-spacecraft (>20) imaging interferometer, utilizing precision formation flying in a stable environment, such as in a Lissajous orbit around the Sun-Earth L2 point. SI's resolution (several 100 times that of HST) will make it an invaluable resource for many other areas of astrophysics, including studies of AGN's, supernovae, cataclysmic variables, young stellar objects, QSO's, and stellar black holes. In this paper, we present an update on the ongoing mission concept and technology development studies for SI. These studies are designed to refine the mission requirements for the science goals, define a Design Reference Mission, perform trade studies of selected major technical and architectural issues, improve the existing technology roadmap, and explore the details of deployment and operations, as well as the possible roles of astronauts and/or robots in construction and servicing of the facility. Title: Imaging Terrestrial Planets Authors: Kochte, M.; Schultz, A. B.; Fraquelli, D.; Jordan, I. J. E.; Lyon, R. G.; Carpenter, K. G.; Hart, H. M.; Disanti, M.; Bruhweiler, F.; Miskey, C.; Rodrigue, M.; Fadali, M. S.; Skelton, D.; Cheng, K. -P. Bibcode: 2004AIPC..713..223K Altcode: We present optical simulations of a new approach to directly image terrestrial planets. Terrestrial planets typically are 10 orders of magnitude fainter than the central star, a difficult challenge for any optical system. Our studies show that the combination of an external occulter and an apodizer yields the required contrast, with significantly reduced requirements on stray light and diffraction. This mitigates the very high mirror tolerances required of other coronagraphic methods and makes exo-planet detection feasible with current technology. Title: The Fizeau Interferometer Testbed (FIT): Developing and Testing the Technologies Needed for Space-Based Interferometric Imaging Systems Authors: Mazzuca, L. M.; Carpenter, K. G.; Lyon, R. G.; Marzouk, J.; Cottle, P.; Dogoda, P.; Huet, H.; Liiva, P.; Petrone, P.; Armstrong, J. T.; Zhang, X.; Mundy, L.; Mozurkewich, D.; Solyar, G. Bibcode: 2004AAS...204.0812M Altcode: 2004BAAS...36..791M The Fizeau Interferometer Testbed (FIT) is a ground-based laboratory experiment at Goddard Space Flight Center (GSFC) designed to develop and test technologies that will be needed for future interferometric spacecraft missions. Specifically, the research from this experiment is a proof-of-concept for optical accuracy and stability, closed-loop control algorithms, optimal sampling methodology of the Fourier UV-plane, computational models for system performance, and image synthesis techniques for a sparse array of 7 to 30 mirrors. It will assess and refine the technical requirements on hardware, control, and imaging algorithms for the Stellar Imager (SI), its pathfinder mission, and other sparse aperture and interferometric imaging mission concepts. This ground-based optical system is a collaborative effort between NASA's GSFC, Sigma Space Corporation, the Naval Research Laboratory, and the University of Maryland. We present an overview of the final optical design, detector system, and data acquisition process. We further compare the expected performance to the actual performance of the testbed using the initial array of seven spherical mirrors. Currently, we have aligned and phased all seven mirrors, demonstrated excellent system stability for extended periods of time, and begun open-loop operations using "pinhole" light sources. Extended scenes and calibration masks are being fabricated and will shortly be installed in the source module. Installation of all the different phase retrieval/diversity algorithms and control software is well on the way to completion, in preparation for future tests of closed-loop operations. Title: The O VI and C III Lines at 1032 and 977 Å in Hyades F Stars Authors: Böhm-Vitense, Erika; Robinson, Richard D.; Carpenter, Kenneth G. Bibcode: 2004ApJ...606.1174B Altcode: We continue our investigations into the mechanisms heating the outer layers of cool dwarf stars. In this study we specifically seek to determine whether in the layers with temperatures around 250,000-300,000 K, in which the O VI lines are emitted, the temperatures are determined by heat conduction from the coronae or by the same processes that heat the lower temperature regions. To study this we discuss here 22 spectra of Hyades F stars taken by the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite to study the O VI lines at 1032 Å and the C III lines at 977 Å and compare them with other lower transition layer lines, observed with HST and IUE, and with existing X-ray data. For our targets with B-V>0.4, the X-ray fluxes of single F stars increase, on average, slowly with increasing B-V, while the O VI line fluxes show the same steep decrease around B-V=0.43 as previously found for the lower temperature transition layer lines. For single stars the X-ray fluxes decrease with increasing vsini, except for the stars with B-V between 0.418 and 0.455, while for the O VI lines, as for the other transition layer lines, fluxes increase with increasing vsini, if vsini is larger than 30 km s-1. For smaller vsini, line fluxes are independent of vsini. The B-V and vsini dependences of the O VI line fluxes are then very different from those of the X-ray fluxes. We thus conclude that for electron temperature Te below 300,000 K, the transition layers for Hyades F stars are not mainly heated by heat conduction from their coronae.

Based on observations made with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer (FUSE) telescope, which is operated for NASA by Johns Hopkins University, under contract NAS5-32985. Title: The Stellar Imager (SI) ``Vision Mission" Authors: Carpenter, K.; Danchi, W.; Leitner, J.; Liu, A.; Lyon, R.; Mazzuca, L.; Moe, R.; Chenette, D.; Schrijver, C.; Kilston, S.; Karovska, M.; Allen, R.; Brown, A.; Marzouk, J.; Murphy, N.; Walter, F. Bibcode: 2004AAS...204.0810C Altcode: 2004BAAS...36..791C The Stellar Imager (SI) is a `Vision' mission in the Sun-Earth Connection (SEC) Roadmap, conceived for the purpose of understanding the effects of stellar magnetic fields, the dynamos that generate them, and the internal structure and dynamics of the stars in which they exist. The ultimate goal is to achieve the best possible forecasting of solar/stellar magnetic activity and its impact on life in the Universe. The science goals of SI require an ultra-high angular resolution, at ultraviolet wavelengths, on the order of 100 micro-arcsec and thus baselines on the order of 0.5 km. These requirements call for a large, multi-spacecraft (>20) imaging interferometer, utilizing precision formation flying in a stable environment, such as in a Lissajous orbit around the Sun-Earth L2 point. SI's resolution will make it an invaluable resource for many other areas of astrophysics, including studies of AGN's, supernovae, cataclysmic variables, young stellar objects, QSO's, and stellar black holes.

We present here an overview of the ongoing mission concept and technology development studies for SI. These studies are designed to refine the mission requirements for the science goals, define a Design Reference Mission, perform trade studies of selected major technical and architectural issues, improve the existing technology roadmap, and explore the details of deployment and operations, as well as the possible roles of astronauts and/or robots in construction and servicing of the facility. Additional information on SI mission concepts and technology can be found at URL: http://hires.gsfc.nasa.gov/ ∼si .

The SI Mission Concept Study is supported, in part, by grants from NASA-HQ through the 2003 Vision Mission NRA. Title: Surprising Differences in the Winds and Mass-Loss Rates of Two M-Giant Stars: Gamma Cru (M3.5III) and Mu Gem (M3III) Authors: Carpenter, K. G.; Robinson, R. D. Bibcode: 2003AAS...203.4902C Altcode: 2003BAAS...35Q1284C We have assessed important parameters of the stellar winds of two very similar M giant stars, Gamma Cru (M3.5III) and Mu Gem (M3III), using high resolution HST/GHRS spectra and found surprising differences in the characteristics of their winds and in their total mass-loss rates. The wind parameters, including flow and turbulent velocities, the optical depth of the wind above the region of photon creation, and the mass-loss rate, have been estimated by fitting line profiles computed using the "Sobolev with Exact Integration" (SEI) radiative transfer code (Lamars et al. 1987), along with simple models of the outer atmospheric structure and wind. These computed profiles are fit to chromospheric emission lines which show self-absorptions produced by the photon-scattering winds of these stars. The SEI code has the advantage of being computationally fast and allows a great number of possible wind models to be examined. The analysis is iterative in nature: we specify estimates of the wind parameters, calculate line profiles for the Mg II (UV1) lines and a range of unblended Fe II lines (which have a wide range of wind opacities and therefore probe different heights in the atmosphere), compare the computed profiles with the observations, and modify the assumed wind properties until the predicted profiles match the observations over as many lines as possible.. Surprisingly, we find that the Gamma Cru wind exhibits a significantly higher terminal velocity, wind turbulence, and mass-loss rate than its fellow M-giant Mu Gem. Title: Imaging terrestrial planets with a free-flying occulter and space telescope: an optical simulation Authors: Schultz, Alfred B.; Lyon, Richard G.; Kochte, Mark; Fraquelli, Dorothy A.; Bruhweiler, Frederick; Jordan, Ian J. E.; Carpenter, Kenneth G.; DiSanti, Michael A.; Miskey, Cherie; Rodrigue, Melodi; Fadali, M. S.; Skelton, Dennis; Hart, Helen M.; Cheng, Kwang-Ping Bibcode: 2003SPIE.5170..262S Altcode: In this manuscript, we further develop our concepts for the free-flying occulter space-based mission, the Umbral Missions Blocking Radiating Astronomical Sources (UMBRAS). Our optical simulations clearly show that an UMBRAS-like mission designed around a 4-m telescope and 10-m occulter could directly image terrestrial planets. Such a mission utilizing existing technology could be built and flown by the end of the decade. Moreover, many of the other proposed concepts for Terrestrial Planet Finder (TPF) could significantly benefit by using an external occulter. We present simultations for an optical design comprising a square aperture telescope plus square external occulter. We show that the entire diffraction pattern, which is propagated from occulter to telescope and through telescope to focal plane, may be characterized by two parameters, the Fresnel number and the ratio of the telescope diameter to the occulter width. Combining the effects of a square occulter with apodization provides a much more rapid roll-off in the PSF intensity between the diffraction spikes than may be achieved with an unapodized telecope aperture and occulter. We parameterize our results with respect to wavefront quality and compare them against other competing methods for exo-planet imaging. The combination of external occulter and apodization yields the required contrast in the region of the PSF essential for exo-planet detection. An occulter external to the telescope (i.e., in a separate spacecraft, as opposed to a classical coronagraph with internal occulter) reduces light scatter within the telescope by approximately 2 orders of magnitude. This is due to less light actually entering the telescope. Reduced scattered light significantly relaxes the constraints on the mirror surface roughness, especially in the mid-spatial frequencies critical for planet detection. This study, plus our previous investigations of engineering as well as spacecraft rendezvous and formation flying clearly indicates that the UMBRAS concept is very competitive with, or superior to, other proposed concepts for TPF missions. Title: Imaging the Surfaces and Interiors of Other Stars: The Stellar Imager (SI) Mission Concept Authors: Carpenter, K. G.; Lyon, R. G.; Schrijver, C. J.; Mundy, L. J.; Allen, R. J.; Rajagopal, J. Bibcode: 2003csss...12.1091C Altcode: The Stellar Imager (SI) is envisioned as a large (0.5 km diameter) space-based, UV-optical interferometer. It is designed to image surface features and, through asteroseismology, sub-surface structures of other stars and measure their spatial and temporal variations. These observations are needed to improve our understanding of the underlying dynamo process(es) and enable improved forecasting of solar/stellar activity and its impact on planetary climates and life. Schrijver and Carpenter (this volume) discuss the science goals of the mission in detail, while in this paper we discuss the performance requirements implied by the science goals and how these translate into specific design requirements on the mission architecture, and we present some preliminary visions for how the required observations (e.g., 1000 pixel, 100 micro-arcsec resolution, UV-optical images of the surface of nearby dwarf stars) for this ambitious project might be obtained. Title: Future Capabilities for Solar/Stellar Observations Authors: Carpenter, K.; Hassler, D.; Berger, T.; Bastian, T.; Pallavicini, R.; Balachandran, S. Bibcode: 2003csss...12..359C Altcode: This session outlines the potential instrumental capabilities for the observation of cool stars and the Sun. The individual contributions cover space-based solar missions (Hassler), ground-based solar optical/IR instruments (Berger), solar-stellar radio capabilities (Bastian), space-based stellar missions (Carpenter), ground-based optical (Pallavicini) and infrared facilities (Balachandran) for stellar observations. Title: Winds from ``Non-Coronal'' and ``Hybrid'' Stars Driven by MHD Waves Authors: Airapetian, V. S.; Carpenter, K.; Ofman, L. Bibcode: 2003AAS...202.3214A Altcode: 2003BAAS...35..745A Observations obtained with IUE, HST and FUSE provide extensive data on atmospheric heating and wind dynamics for late-type luminous stars. The physical processes which drive winds in these stars are poorly understood, despite decades of study. In our previous study we have shown that observational signatures of winds can be interpreted by our model of winds driven by propagated Alfvén waves in stellar atmospheres and launched at a single frequency at the wind base (Airapetian et al. 2000). We extend our MHD calculations of winds from luminous late-type stars to include an Alfvén wave driver with a broad-band frequency range. The calculations are applied to ``non-coronal'' (α Tau) and ``hybrid'' (β Dra) giant stars to consistently reproduce the observed velocity profiles of the winds, its terminal velocity, the turbulent broadening of UV lines and mass loss rates. The nature of wind variability in luminous late-type stars is discussed. We also present the preliminary results of our first MHD and LTE radiative transfer calculations to model the UV spectra from the K5 giant, α Tau.

This research is supported by the NASA Research grant from GSFC No. NAG5-12869. Title: A novel process to fabricate mirrors with very long radius and ultrasmooth surfaces Authors: Chen, Peter C.; Carpenter, Kenneth G.; Romeo, Robert C. Bibcode: 2003SPIE.4854...21C Altcode: During the course of performing space flight qualification testing of composite mirrors at NASA GSFC, a serendipitious event was observed which, in retrospect, should have been obvious. Investigation of this phenomenon leads to a promising avenue towards the fabrication of large aperture precision spherical mirrors with very long radius of curvature (>f/100). Such mirrors are required for future missions such as the Stellar Imager. We report on the observation and analysis of the event, optical measurements, and the development of associated active figure control systems. Title: Simulating dilute-aperture imaging: The Stellar Imager Authors: Rajagopal, Jayadev K.; Böker, Torsten; Allen, Ronald J.; Carpenter, Kenneth G. Bibcode: 2003SPIE.4852..652R Altcode: A number of proposed space missions for high resolution imaging at wavelengths ranging from IR to UV call for ``dilute-aperture'' Fizeau-mode interferometers. We present here details of a software tool developed for high fidelity simulations of images obtained with such instruments. We show simulated images from the Stellar Imager, a mission concept being developed by NASA's GSFC to obtain high-resolution images of nearby stars in UV-optical wavelengths. Using the simulator, we study the capability of the proposed SI design to image stellar surfaces. We use the simulator to explore parameters of image quality such as resolution and dynamic range, and to evaluate proposed designs and the feasibility of science goals. Title: Stellar Imager (SI) mission concept Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Lyon, Richard G.; Mundy, Lee G.; Allen, Ronald J.; Armstrong, J. Thomas; Danchi, William C.; Karovska, Margarita; Marzouk, Joseph; Mazzuca, Lisa M.; Mozurkewich, David; Neff, Susan G.; Pauls, Thomas A.; Rajagopal, Jayadev K.; Solyar, Gregory; Zhang, Xiaolei Bibcode: 2003SPIE.4854..293C Altcode: The Stellar Imager (SI) is envisioned as a space-based, UV-optical interferometer composed of 10 or more one-meter class elements distributed with a maximum baseline of 0.5 km. It is designed to image stars and binaries with sufficient resolution to enable long-term studies of stellar magnetic activity patterns, for comparison with those on the sun. It will also support asteroseismology (acoustic imaging) to probe stellar internal structure, differential rotation, and large-scale circulations. SI will enable us to understand the various effects of the magnetic fields of stars, the dynamos that generate these fields, and the internal structure and dynamics of the stars. The ultimate goal of the mission is to achieve the best-possible forecasting of solar activity as a driver of climate and space weather on time scales ranging from months up to decades, and an understanding of the impact of stellar magnetic activity on life in the Universe. In this paper we describe the scientific goals of the mission, the performance requirements needed to address these goals, the "enabling technology" development efforts being pursued, and the design concepts now under study for the full mission and a possible pathfinder mission. Title: UMBRAS: a matched occulter and telescope for imaging extrasolar planets Authors: Schultz, Alfred B.; Jordan, Ian J.; Kochte, Mark; Fraquelli, Dorothy A.; Bruhweiler, Fred; Hollis, Jan M.; Carpenter, Kenneth G.; Lyon, Richard G.; DiSanti, Mike A.; Miskey, Cherie L.; Leitner, Jesse; Burns, Richard D.; Starin, Scott R.; Rodrigue, Melodi; Fadali, M. S.; Skelton, Dennis L.; Hart, Helen M.; Hamilton, Forrest C.; Cheng, Kwang-Ping Bibcode: 2003SPIE.4860...54S Altcode: We describe a 1-meter space telescope plus free-flying occulter craft mission that would provide direct imaging and spectroscopic observations of Jovian and Uranus-sized planets about nearby stars not detectable by Doppler techniques. The Doppler technique is most sensitive for the detection of massive, close-in extrasolar planets while the use of a free-flying occulter would make it possible to image and study stellar systems with planets comparable to our own Solar System. Such a mission with a larger telescope has the potential to detect earth-like planets. Previous studies of free-flying occulters reported advantages in having the occulting spot outside the telescope compared to a classical coronagraph onboard a space telescope. Using an external occulter means light scatter within the telescope is reduced due to fewer internal obstructions and less light entering the telescope and the polishing tolerances of the primary mirror and the supporting optics can be less stringent, thereby providing higher contrast and fainter detection limits. In this concept, the occulting spot is positioned over the star by translating the occulter craft, at distances of 1,000 to 15,000 kms from the telescope, on the sky instead of by moving the telescope. Any source within the telescope field-of-view can be occulted without moving the telescope. In this paper, we present our current concept for a 1-m space telescope matched to a free-flying occulter, the Umbral Missions Blocking Radiating Astronomical Sources (UMBRAS) space mission. An UMBRAS space mission consists of a Solar Powered Ion Driven Eclipsing Rover (SPIDER) occulter craft and a matched (apodized) telescope. The occulter spacecraft would be semi-autonomous, with its own propulsion systems, internal power (solar cells), communications, and navigation capability. Spacecraft rendezvous and formation flying would be achieved with the aid of telescope imaging, RF or laser ranging, celestial navigation inputs, and formation control algorithms. Title: The Stellar Imager (SI): An Ultra-High Angular Resolution Ultraviolet/Optical Observatory Authors: Carpenter, K. G.; Lyon, R. G.; Schrijver, C. J.; Mundy, L.; Allen, R. J.; Rajagopal, J. Bibcode: 2003ASPC..291..355C Altcode: 2003hslf.conf..355C No abstract at ADS Title: The Fizeau Interferometer Testbed Authors: Zhang, Xiaolei; Carpenter, Kenneth G.; Lyon, Richard G.; Huet, Hubert; Marzouk, Joe; Solyar, Gregory Bibcode: 2002astro.ph.12439Z Altcode: The Fizeau Interferometer Testbed (FIT) is a collaborative effort between NASA's Goddard Space Flight Center, the Naval Research Laboratory, Sigma Space Corporation, and the University of Maryland. The testbed will be used to explore the principles of and the requirements for the full, as well as the pathfinder, Stellar Imager mission concept. It has a long term goal of demonstrating closed-loop control of a sparse array of numerous articulated mirrors to keep optical beams in phase and optimize interferometric synthesis imaging. In this paper we present the optical and data acquisition system design of the testbed, and discuss the wavefront sensing and control algorithms to be used. Currently we have completed the initial design and hardware procurement for the FIT. The assembly and testing of the Testbed will be underway at Goddard's Instrument Development Lab in the coming months. Title: Steps Toward a Large Space-Based UV/Optical Fizeau Interferometer: The GSFC Fizeau Interferometer Testbed (FIT) Authors: Carpenter, K. G.; Lyon, R. G.; Mazzuca, L. M.; Solyar, G.; Marzouk, J.; Mundy, L. G.; Armstrong, J. T.; Zhang, X. Bibcode: 2002AAS...201.8209C Altcode: 2002BAAS...34.1240C Goddard Space Flight Center is pursuing the development of space-based, long-baseline (>0.5km) UV-optical Fizeau imaging interferometers to enable the next major stride toward very high angular resolution astronomical observations. This effort includes the development and operation of the Fizeau Interferometry Testbed (FIT), in collaboration with the Naval Research Lab/NPOI, Univ. of MD, and Sigma Space Corporation. The FIT will be used to explore the principles of and requirements for the Stellar Imager (SI) mission concept (http://hires.gsfc.nasa.gov/ ~si) and other such Fizeau Interferometers/Sparse Aperture Telescope missions, leading in the end to the Planet Imager (PI), which is the ultimate goal of the current Origins Program. The primary goal of the FIT program is to demonstrate closed-loop control of mirrors (tip, tilt, piston, translation of array elements) and the overall system to keep the optical beams in phase and enable high quality imaging by a many-element (7-30) Fizeau Interferometric System. The FIT will also be used to assess various wavefront reconstruction and sensing and image reconstruction algorithms for utility and accuracy by application to real data generated by the Testbed. In this paper, we describe the design and goals of the system, provide a status report on its construction, and note our future plans. The FIT development is supported by NASA-ROSS/SARA grants to GSFC, UMD, and NRL and by internal GSFC R&D funds. Title: The Stellar Imager (SI): An UV-Optical Interferometer in Space Authors: Zhang, X.; Carpenter, K.; Schrijver, C. Bibcode: 2002AAS...200.6102Z Altcode: 2002BAAS...34..744Z The Stellar Imager (SI) is envisioned as a space-based, UV-optical interferometer composed of 10 or more one-meter class mirrors distributed with a maximum baseline of 0.5 km and providing a resolution of 60 micro-arcseconds at 1550 A. It will image stars and binaries with one hundred to one thousand resolution elements on their surfaces and enable long-term studies of stellar magnetic activity patterns and their evolution with time, for comparison with those on the sun. It will also sound their interiors through asteroseismology to image internal structure, differential rotation, and large-scale circulations. SI will enable us to understand the various effects of magnetic fields of stars, the dynamos that generate them, and the internal structure and dynamics of the stars in which they exist. The ultimate goal is to achieve the best-possible forecasting of solar activity on times scales ranging up to decades, and an understanding of the impact of stellar magnetic activity on life in the Universe. With substantial improvements in normal-incidence mirror coatings for the EUV, the concept could be extended into that shorter wavelength regime as well. Fitting naturally within the NASA long-term time line, SI complements defined missions, and with them will show us entire other solar systems, from the central star to their orbiting planets. Title: What Is Happening at Spectral Type F5 in Hyades F Stars? Authors: Böhm-Vitense, Erika; Robinson, Richard; Carpenter, Kenneth; Mena-Werth, Jose Bibcode: 2002ApJ...569..941B Altcode: Aiming at a better understanding of the mechanisms heating the chromospheres, transition regions, and coronae of cool stars, we study ultraviolet, low-resolution Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra of Hyades main-sequence F stars. We study the B-V dependence(s) of the chromospheric and transition layer emission line fluxes and their dependences on rotational velocities. We find that the transition layer emission line fluxes and also those of strong chromospheric lines decrease steeply between B-V=0.42 and 0.45, i.e., at spectral type F5, for which the rotational velocities also decrease steeply. The magnitude of the line-flux decrease increases for lines of ions with increasing degree of ionization. This shows that the line-flux decrease is not due to a change in the surface filling factor but rather due to a change of the relative importance of different heating mechanisms. For early F stars with B-V<0.42 we find for the transition layer emission lines increasing fluxes for increasing vsini, indicating magnetohydrodynamic heating. The vsini dependence is strongest for the high-ionization lines. On the other hand, the low chromospheric lines show no dependence on vsini, indicating acoustic shock heating for these layers. This also contributes to the heating of the transition layers. The Mg II and Ca II lines show decreasing fluxes for increasing vsini, as long as vsini is less than ~40 km s-1. The coronal X-ray emission also decreases for increasing vsini, except for vsini larger than ~100 km s-1. We have at present no explanation for this behavior. For late F stars the chromospheric lines show vsini dependences similar to those observed for early F stars, again indicating acoustic heating for these layers. We were unable to determine the vsini dependence of the transition layer lines because of too few single star targets. The decrease of emission line fluxes at the spectral type F5, with steeply decreasing vsini, indicates, however, a decreasing contribution of magnetohydrodynamic heating for the late F stars. The X-ray emission for the late F stars increases for increasing vsini, indicating magnetohydrodynamic heating for the coronae of the late F stars, different from the early F stars. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. Title: Estimation of Mass-Loss Rates for M Giants from UV Emission Line Profiles Authors: Carpenter, K. G.; Robinson, R. D. Bibcode: 2001AAS...199.9205C Altcode: 2001BAAS...33.1441C The photon-scattering winds of M giants produce absorption features in the strong chromospheric emission lines. These provide us with an opportunity to assess important parameters of the wind, including flow and turbulent velocities, the optical depth of the wind above the region of photon creation, and the star's mass-loss rate. We have used the Lamers et al. (1987) Sobolev with Exact Integration (SEI) radiative transfer code, along with simple models of the outer atmospheric structure and wind, to determine the wind characteristics of two M-giant stars, γ Cru (M3.4) and μ Gem (M3IIIab). The SEI code has the advantage of being computationally fast and allows a great number of possible wind models to be examined. The analysis procedure involves specifying wind parameters and then using the program to calculate line profiles for the Mg II (UV1) lines and a range of unblended Fe II lines. These lines have a wide range of wind opacities and therefore probe different heights in the atmosphere. The assumed wind properties are iterated until the predicted profiles match the observations over as many lines as possible. We present estimates of the wind parameters for these stars and offer a comparison to wind properties previously-derived for low-gravity K stars using the same technique. Title: Free-flying Occulters for Use with Space Telescopes Authors: Kochte, M.; Schultz, A. B.; Jordan, I.; Hamilton, F.; Bruhweiler, F.; DiSanti, M. A.; Burns, R. D.; Carpenter, K.; Hollis, J. M.; Leitner, J.; Lyon, R. G.; Starin, S.; Fadali, M. S.; Rodrigue, M.; Skelton, D. L.; Hart, H. M. Bibcode: 2001AAS...199.4501K Altcode: 2001BAAS...33Q1367K We summarize a free-flying occulter proposal that was submitted to NASA in response to NRA-01-OSS-04. Free-flying occulters in association with space telescopes have been proposed for nearly four decades to detect and study extrasolar planets. External occulters reduce the magnitude differences between a planet and the host star; light scatter within the telescope is reduced resulting from fewer obstructions and optical surfaces; and any instrument onboard the telescope, including spectrometers, can be used to study extrasolar planets. We conclude with a mission concept for an optimized optical 1-m space telescope with a small external occulter. Both craft could be launched from a single launch vehicle and placed in a 1-AU fall-away orbit or at Earth-Sun L2. Jovian planets around stars within 10 parsecs could be studied, and a search for sub-Jovian planets around the nearest handful of stars could be performed. Approximately 80% of the telescope time would be available for projects not associated with the external occulter such as gravitational lensing and planetary transit surveys. Title: Goddard High Resolution Spectrograph Observations of NGC 4151 Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Snow, M.; Ake, T. B. Bibcode: 2001AJ....121.2999B Altcode: Goddard High Resolution Spectrograph observations of the nucleus of the bright, nearby Seyfert galaxy NGC 4151 are presented andbriefly described. Title: AB Dor in '94. I. Hubble Space Telescope Goddard High Resolution Spectrogaph Observations of the Quiescent Chromosphere of an Active Star Authors: Brandt, J. C.; Heap, S. R.; Walter, F. M.; Beaver, E. A.; Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.; Trafton, L. M.; Weymann, R. J.; Norman, D.; Redfield, S. Bibcode: 2001AJ....121.2173B Altcode: We analyze Hubble Space Telescope/Goddard High Resolution Spectrograph spectra of AB Doradus, the prototypical, ultrarapidly rotating K dwarf. We observed chromospheric (Mg II) and transition-region (C II, Si IV, C IV, and N V) lines periodically throughout the stellar rotation period and provide a low-dispersion stellar atlas of 78 emission lines. The quiescent line profiles of the chromospheric and transition-region lines show narrow cores superposed on very broad wings. The broad wings of the Mg II k and h lines and of the transition-region lines can be explained by emission from gas corotating with the star and extending out to near the Keplerian corotation radius (2.8 stellar radii). While this is not a unique solution, it is consistent with previous studies of Hα emission, which are naturally explained by large corotating prominences. We find no evidence for rotational modulation of the emission-line fluxes. The density diagnostics suggest that the transition region is formed at constant pressure, with an electron density of 2-3×1012 cm-3 at a temperature of 3×104 K. The electron pressure is about 100 times larger than that for the quiet Sun. The emission-measure distribution shows a minimum between logT=5 and 5.5. The Mg II line exhibits three interstellar absorption components along the 15 pc line of sight. We identify the lowest velocity component with the G Cloud, but the other components are not identified with any interstellar clouds previously detected from other lines of sight. Title: Mg II Emission Lines of Hyades F Stars Authors: Böhm-Vitense, Erika; Mena-Werth, Jose; Carpenter, Kenneth G.; Robinson, Richard D. Bibcode: 2001ApJ...550..457B Altcode: With the Hubble Space Telescope (HST) we have observed Hyades F stars, using the Space Telescope Imaging Spectrograph (STIS), in order to get more information about the heating mechanism(s) for the chromospheres and transition layers and their dependence on rotation and age. In this paper we study the Mg II lines at 2800 Å. We include earlier observations with the International Ultraviolet Explorer (IUE) satellite. The Mg II emission lines become observable for B-V>0.3. The emission line fluxes increase steeply until B-V~0.40. For single stars there is a steep decrease in flux between B-V=0.41 and B-V=0.44, similar to the behavior of the Ca II emission line cores. For larger B-V the Mg II emission line fluxes again increase, but much more slowly than for the Ca II lines. Generally, the low point of the emission is reached between B-V=0.43 and B-V=0.45, i.e., similar to the Ca II emission cores. For the Hyades F stars there appears to be a difference between the emissions for single stars and those for binaries. We find that for Hyades stars with surface line fluxes larger than 106 ergs cm-2 s-1 the emission line fluxes decrease with increasing vsini. For smaller fluxes they may increase with increasing vsini. We have only three stars that perhaps show this. We study the flux ratios of the Mg II k and h lines at 2795.7 and 2802.5 Å in order to determine where the lines fall on the curve of growth. For the earliest F stars studied here the ratio is close to 2, as expected for optically thin lines. Generally, it seems that the optical depths in the line centers are less than 10. There remain problems in understanding the size of the line widths. We discuss the interpretation of the Wilson-Bappu effect. For the Hyades F stars there is a strong dependence of the line width on the effective temperature. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy. Incorporated, under NASA contract NAS5-26555. Title: The Stellar Imager (SI) mission concept Authors: Carpenter, Kenneth G.; Neff, Susan G.; Schrijver, Carolus J.; Allen, Ronald J.; Rajagopal, Jay Bibcode: 2001LIACo..36..177C Altcode: 2001fomi.conf..177C The Stellar Imager (SI) is envisioned as a space-based, UV-optical interferometer composed of 10 or more one-meter class elements distributed with a maximum baseline of 0.5 km. It will image stars and binaries with one hundred to one thousand resolution elements on their surface and enable long-term studies of stellar magnetic activity patterns and their evolution with time, for comparison with those on the sun. It will also sound their interiors through asteroseismology to image internal structure, differential rotation, and large-scale circulations. SI will enable us to understand the various effects of magnetic fields of stars, the dynamos that generate them, and the internal structure and dynamics of the stars in which they exist. The ultimate goal is to achieve the best-possible forecasting of solar activity on times scales ranging up to decades, and an understanding of the impact of stellar magnetic activity on astrobiology and life in the Universe. The road to that goal will revolutionize our understanding of stars and stellar systems, the building blocks of the Universe. Fitting naturally within the NASA and ESA long-term time lines, SI complements defined missions, and with them will show us entire other solar systems, from the central star to their orbiting planets. In this paper we will describe the scientific goals of the mission, the performance requirements needed to address those goals, and the design concepts now under study. Title: Far-UV Echelle Spectroscopy of Arcturus with HST STIS (CD-ROM Directory: contribs/ayres) Authors: Ayres, T. R.; Brown, A.; Harper, G. M.; Bennett, P. D.; Linsky, J. L.; Carpenter, K. G.; Robinson, R. D. Bibcode: 2001ASPC..223.1079A Altcode: 2001csss...11.1079A No abstract at ADS Title: Estimation of Mass-Loss Rates from Emission Line Profiles in the UV Spectra of Cool Stars (CD-ROM Directory: contribs/carpente) Authors: Carpenter, K. G.; Robinson, R. D.; Harper, G. M. Bibcode: 2001ASPC..223.1591C Altcode: 2001csss...11.1591C No abstract at ADS Title: Coordinated Optical, Radio and EUV Observations of a Flare on YZ CMi (CD-ROM Directory: contribs/robinson) Authors: Robinson, R. D.; Airapetian, V.; Slee, O. B.; Mathioudakis, M.; Carpenter, K. G. Bibcode: 2001ASPC..223.1151R Altcode: 2001csss...11.1151R No abstract at ADS Title: AB Dor in '94: I. HST/GHRS Observations of the Quiescent Chromosphere of an Active Star Authors: Brandt, J. C.; Heap, S. R.; Walter, F. M.; Beaver, E. A.; Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.; Trafton, L. M.; Weymann, R. J.; Norman, D.; Redfield, S. Bibcode: 2000astro.ph.12487B Altcode: We analyze HST/GHRS spectra of AB Doradus, the prototypical ultra-rapidly rotating K dwarf. We observed chromospheric (Mg II) and transition region (C II, Si IV, C IV, and N V) lines periodically throughout the stellar rotation period, and provide a low dispersion stellar atlas of 78 emission lines. The quiescent line profiles of the chromospheric and transition region lines show narrow cores superposed on very broad wings. The broad wings of the Mg II k & h lines and of the transition region lines can be explained by emission from gas co-rotating with the star and extending out to near the Keplerian co-rotation radius (2.8 stellar radii). While this is not a unique solution, it is consistent with previous studies of H-alpha emission that are naturally explained by large co-rotating prominences. We find no evidence for rotational modulation of the emission line fluxes. The density diagnostics suggest that the transition region is formed at constant pressure, with an electron density 2-3 E12 /cm^3 at a temperature of 30,000 K. The electron pressure is about 100 times larger than that for the quiet Sun. The emission measure distribution shows a minimum between log(T) = 5 and 5.5. The Mg II line exhibits three interstellar absorption components along the 15 pc line of sight. We identify the lowest velocity component with the G cloud, but the other components are not identified with any interstellar clouds previously detected from other lines of sight. Title: Ultraviolet Emission Lines in BA and Non-BA Giants Authors: Böhm-Vitense, Erika; Carpenter, Kenneth G.; Robinson, Richard D. Bibcode: 2000ApJ...545..992B Altcode: With the Hubble Space Telescope (HST) and the Goddard High Resolution Spectrograph we have observed four barium and three weak barium stars in the ultraviolet spectral region, together with two nonpeculiar giant standard stars. An additional suspected Ba star was observed with HST and the Space Telescope Imaging Spectrograph. In the H-R diagram, three of the observed Ba stars lie on the same evolutionary tracks as the Hyades giants. Using International Ultraviolet Explorer (IUE) spectra of previously studied giants together with our HST spectra, we investigate whether the chromospheric and transition layer emission-line spectra of the Ba stars are different from those of nonpeculiar giants and from those of giants with peculiar carbon and/or nitrogen abundances. Except for the Ba star HD 46407 and the suspected Ba star HD 65699, the Ba star and mild Ba star emission-line fluxes are, for a given effective temperature and for a given luminosity, lower than those for the nonpeculiar giants observed with IUE. In comparison with the HST-observed standard stars, the C IV λ1550-to-C II λ1335 line flux ratios are smaller, but not necessarily so in comparison with all IUE-observed nonpeculiar giants. However, the C IV-to-C II line flux ratios for the Ba stars decrease with increasing carbon abundances. This shows that the energy balance in the lower transition layer is influenced by the carbon abundance. The temperature gradient appears to be smaller in the C II line-emitting region. There does not seem to be a difference in chromospheric electron densities for the Ba and non-Ba stars, though this result is rather uncertain. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Title: The Stellar Imager (SI) Mission Concept Authors: Carpenter, K. G.; Schrijver, C. J. Bibcode: 2000AAS...197.1410C Altcode: 2000BAAS...32.1426C The Stellar Imager (SI) is envisioned as a space-based, UV-optical interferometer composed of 10 or more one-meter class elements distributed with a maximum baseline of 0.5 km. It will image stars and binaries with one hundred to one thousand resolution elements on their surface and enable long-term studies of stellar magnetic activity patterns and their evolution with time, for comparison with those on the sun. It will also sound their interiors through asteroseismology to image internal structure, differential rotation, and large-scale circulations. SI will enable us to understand the various effects of magnetic fields of stars, the dynamos that generate them, and the internal structure and dynamics of the stars in which they exist. The ultimate goal is to achieve the best-possible forecasting of solar activity on times scales ranging up to decades, and an understanding of the impact of stellar magnetic activity on astrobiology and life in the Universe. The road to that goal will revolutionize our understanding of stars and stellar systems, the building blocks of the Universe. Fitting naturally within the NASA long-term time line, SI complements defined missions, and with them will show us entire other solar systems, from the central star to their orbiting planets. Title: A Dream of a Mission: Stellar Imager and Seismic Probe Authors: Carpenter, K. G.; Schrijver, C. J. Bibcode: 2000AAS...196.3207C Altcode: 2000BAAS...32..721C The Stellar Imager and Seismic Probe (SISP) is a mission to understand the various effects of magnetic fields of stars, the dynamos that generate them, and the internal structure and dynamics of the stars in which they exist. The ultimate goal is to achieve the best-possible forecasting of solar activity on times scales ranging up to decades, and an understanding of the impact of stellar magnetic activity on astrobiology and life in the Universe. The road to that goal will revolutionize our understanding of stars and stellar systems, the building blocks of the Universe. SISP will zoom in on what today - with few exceptions - we only know as point sources, revealing processes never before seen, thus providing a tool to astrophysics as fundamental as the microscope is to the study of life on Earth. SISP is an ultraviolet aperture-synthesis imager with 8-10 telescopes with meter-class apertures, and a central hub with focal-plane instrumentation that allows spectrophotometry in passbands as narrow as a few Angstroms up to hundreds of Angstroms. SISP will image stars and binaries with one hundred to one thousand resolution elements on their surface, and sound their interiors through asteroseismology to image internal structure, differential rotation, and large-scale circulations; this will provide accurate knowledge of stellar structure and evolution and complex transport processes, and will impact numerous branches of (astro)physics ranging from the Big Bang to the future of the Universe. Fitting naturally within the NASA long-term time line, SISP complements defined missions, and with them will show us entire other solar systems, from the central star to their orbiting planets. Title: A dream of a mission: the stellar imager and seismic probe. Authors: Schrijver, C. J.; Carpenter, K. G. Bibcode: 2000BAAS...32R.828S Altcode: No abstract at ADS Title: A dream of a mission: the Stellar Imager and Seismic Probe Authors: Schrijver, C. J.; Carpenter, K. G. Bibcode: 2000SPD....31.0298S Altcode: 2000BAAS...32..828S The Stellar Imager and Seismic Probe (SISP) is a mission to understand the various effects of magnetic fields of stars, the dynamos that generate them, and the internal structure and dynamics of the stars in which they exist. The ultimate goal is to achieve the best-possible forecasting of solar activity on times scales ranging up to decades, and an understanding of the impact of stellar magnetic activity on astrobiology and life in the Universe. The road to that goal will revolutionize our understanding of stars and stellar systems, the building blocks of the Universe. SISP represents an advance in image detail of several hundred times over the Hubble Space Telescope. SISP will zoom in on what today - with few exceptions - we only know as point sources, revealing processes never before seen, thus providing a tool to astrophysics as fundamental as the microscope is to the study of life on Earth. SISP is an ultraviolet aperture-synthesis imager with 8-10 telescopes with meter-class apertures, and a central hub with focal-plane instrumentation that allows spectrophotometry in passbands as narrow as a few Angstroms up to hundreds of Angstroms. SISP will image stars and binaries with one hundred to one thousand resolution elements on their surface, and sound their interiors through asteroseismology to image internal structure, differential rotation, and large-scale circulations; this will provide accurate knowledge of stellar structure and evolution and complex transport processes, and will impact numerous branches of (astro)physics ranging from the Big Bang to the future of the Universe. Fitting naturally within the NASA long-term time line, SISP complements defined missions, and with them will show us entire other solar systems, from the central star to their orbiting planets. Title: Do All BA II Stars Have White Dwarf Companions? Authors: Böhm-Vitense, Erika; Carpenter, Kenneth; Robinson, Richard; Ake, Tom; Brown, Jeffery Bibcode: 2000ApJ...533..969B Altcode: With the Hubble Space Telescope (HST) and the Goddard High Resolution Spectrograph (GHRS) we have observed four barium stars, three mild barium stars, and one weak G-band star in the ultraviolet spectral region. One barium star was observed with HST and the Space Telescope Imaging Spectrograph (STIS). The aim was to check the hypothesis that all these peculiar stars have white dwarf (WD) companions, which at their asymptotic giant branch phase transferred mass with peculiar element abundances to the present barium and CH peculiar stars. Assuming that the ultraviolet continua of the cool giants, including the barium stars, are generated in their chromospheres and that the relations between the continua and the emission lines created in the chromospheres and transition layers are similar in field giants and barium stars, we found that, indeed, most of our target barium and weak barium stars appear to have excess flux in the UV when compared to standard giant stars. For most of the stars the excess flux can be attributed to WD companions with temperatures between 10,000 and 12,000 K, if the WD mass is about 0.6 Msolar. Cooling times for the WDs were derived from their effective temperatures and model calculations by M. Wood. The calculated cooling times are longer than the lifetimes of the barium stars on the giant branch. For our target stars the mass transfer therefore happened while they were still on the main sequence. For two of the mild barium stars and one or perhaps two barium stars the derived cooling times for the WD companions come out to be longer than the total evolutionary times of the barium stars as calculated by Schaller et al. If our derivations are correct (the error bars are rather large) then either evolutionary models with larger convective overshoot have to be used for the barium stars or the cooling times of the white dwarfs have to be revised downward. Possibly an additional (as yet unknown) cooling mechanism has to be considered? The weak G-band star HD 165634, which has a carbon underabundance of about a factor of 10, also appears to have a WD companion. We discuss the implications of this very low carbon abundance. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy. Incorporated, under NASA contract NAS5-26555. Title: Critical Complements: Progress on the Orbit of T Mon Authors: Evans, N. R.; Carpenter, K.; Robinson, R.; Massa, D.; Wahlgren, G. M.; Vinkó, J.; Szabados, L. Bibcode: 2000ASPC..203..246E Altcode: 2000IAUCo.176..246E; 2000ilss.conf..246E A preliminary orbit has been derived for the high luminosity, 27-d classical Cepheid T Mon. Velocities for the hot companion have been measured from an HST GHRS spectrum and 3 IUE spectra. The companion velocities are inconsistent with binary orbital motion and it is likely that the companion is itself a short period binary. The HST spectrum also shows that the companion is a chemically peculiar star, probably magnetic. Title: Winds from Luminous Late-Type Stars. I. The Effects of Nonlinear Alfvén Waves Authors: Airapetian, V. S.; Ofman, L.; Robinson, R. D.; Carpenter, K.; Davila, J. Bibcode: 2000ApJ...528..965A Altcode: We present the results of magnetohydrodynamic (MHD) modeling of winds from luminous late-type stars using a 2.5-dimensional, nonlinear MHD computer code. We assume that the wind is generated within an initially hydrostatic atmosphere and is driven by torsional Alfvén waves generated at the stellar surface. Two cases of atmospheric topology are considered: case I has longitudinally uniform density distribution and isotropic radial magnetic field over the stellar surface, and case II has an isotropic, radial magnetic field with a transverse density gradient, which we refer to as an ``atmospheric hole.'' We use the same set of boundary conditions for both models.The calculations are designed to model a cool luminous star, for which we assume an initial hydrostatic pressure scale height of 0.072 R*, an Alfvén wave speed of 92 km s-1 at the surface, and a wave period of 76 days, which roughly corresponds with the convective turnover time. For case I the calculations produce a wind with terminal velocity of ~22 km s-1 and a mass loss rate comparable to the expected value of 10-6 Msolar yr-1. For case II we predict a two-component wind: a fast (25 km s-1) and relatively dense wind outside of the atmospheric hole and a slow (15 km s-1), rarefied wind inside of the hole. Title: Toward an Orbit for the High-Luminosity Cepheid T Monocerotis Authors: Evans, Nancy Remage; Carpenter, Kenneth; Robinson, Richard; Massa, Derck; Wahlgren, Glenn M.; Vinko, Jozsef; Szabados, Laszlo Bibcode: 1999ApJ...524..379E Altcode: We have obtained new velocities of the long-period Cepheid T Mon from the ground and velocities of its hot companion with the Hubble Space Telescope (HST) and the International Ultraviolet Explorer (IUE). Although observations do not cover a full orbit, both the maximum and minimum orbital velocities have now been obtained. We present a preliminary orbit and discuss the uncertainties in the orbital parameters. The velocities for the companion appear to be inconsistent with binary orbital motion, and it is likely that the companion is itself a binary in a short-period orbit. The HST spectrum of the companion shows that it is a chemically peculiar star, probably magnetic. Because it is coupled with the more massive Cepheid, it must be very close to the zero-age main sequence. The well-determined mass function from the preliminary orbit implies that the inclination of the long-period system is close to 90°.

Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NASA-26555 Title: GHRS Observations of Cool, Low-Gravity Stars. V. The Outer Atmosphere and Wind of the Nearby K Supergiant λ Velorum Authors: Carpenter, Kenneth G.; Robinson, Richard D.; Harper, Graham M.; Bennett, Philip D.; Brown, Alexander; Mullan, Dermott J. Bibcode: 1999ApJ...521..382C Altcode: UV spectra of λ Velorum taken with the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope are used to probe the structure of the outer atmospheric layers and wind and to estimate the mass-loss rate from this K5 Ib-II supergiant. VLA radio observations at λ=3.6 cm are used to obtain an independent check on the wind velocity and mass-loss rate inferred from the UV observations. Parameters of the chromospheric structure are estimated from measurements of UV line widths, positions, and fluxes and from the UV continuum flux distribution. The ratios of optically thin C II] emission lines indicate a mean chromospheric electron density of logNe~8.9+/-0.2 cm-3. The profiles of these lines indicate a chromospheric turbulence (v0~25-36 km s-1), which greatly exceeds that seen in either the photosphere or wind. The centroids of optically thin emission lines of Fe II and of the emission wings of self-reversed Fe II lines indicate that they are formed in plasma approximately at rest with respect to the photosphere of the star. This suggests that the acceleration of the wind occurs above the chromospheric regions in which these emission line photons are created. The UV continuum detected by the GHRS clearly traces the mean flux-formation temperature as it increases with height in the chromosphere from a well-defined temperature minimum of 3200 K up to about 4600 K. Emission seen in lines of C III] and Si III] provides evidence of material at higher than chromospheric temperatures in the outer atmosphere of this noncoronal star. The photon-scattering wind produces self-reversals in the strong chromospheric emission lines, which allow us to probe the velocity field of the wind. The velocities to which these self-absorptions extend increase with intrinsic line strength, and thus height in the wind, and therefore directly map the wind acceleration. The width and shape of these self-absorptions reflect a wind turbulence of ~9-21 km s-1. We further characterize the wind by comparing the observations with synthetic profiles generated with the Lamers et al. Sobolev with Exact Integration (SEI) radiative transfer code, assuming simple models of the outer atmospheric structure. These comparisons indicate that the wind in 1994 can be described by a model with a wind acceleration parameter β~0.9, a terminal velocity of 29-33 km s-1, and a mass-loss rate~3×10-9 Msolar yr-1. Modeling of the 3.6 cm radio flux observed in 1997 suggests a more slowly accelerating wind (higher β) and/or a higher mass-loss rate than inferred from the UV line profiles. These differences may be due to temporal variations in the wind or from limitations in one or both of the models. The discrepancy is currently under investigation.

Based on observations with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Title: STIS UV Atlas of the Red Giant Arcturus(1) Authors: Ayres, T. R.; Brown, A.; Harper, G. M.; Bennett, P. D.; Linsky, J. L.; Carpenter, K. G.; Robinson, R. D. Bibcode: 1999AAS...194.6701A Altcode: 1999BAAS...31..930A The Space Telescope Imaging Spectrograph (STIS) conducted a series of observations of the archetype ``noncoronal'' red giant Arcturus (HD 124897; alpha Boo; K1 III) on 24 August 1998, 17--23 UT. The STIS program was the result of a failed cycle 5 pointing, which could not be rescheduled during the abbreviated cycle 6, and was carried over to cycle 7. Three grating settings---E230H (t_exp= 1340 s), E230M (2493 s), and E140M (5208 s)---covered the ultraviolet spectrum from 1150--2850 Angstroms, at resolutions between R ~ 4*E(4) - 1*E(5) , with essentially no gaps. The resulting spectrograms are stunning. The resolution is very high, as is the S/N; the spectral coverage is broad and comprehensive. The far-UV interval (1150--1700 Angstroms) is a rich emission line spectrum, dominated by the broad resonance transitions of atomic hydrogen (lambda 1215) and oxygen (lambda 1305 triplet). There are numerous narrow emissions, mostly from low-excitation species such as Si I, Fe II, and fluoresced bands of carbon monoxide. Surprisingly, high-excitation species---Si IV (lambda 1393: 6*E(4) K) and C IV (lambda 1548: 1*E(5) K)---are present as well (as seen in the earlier ``failed'' GHRS spectra). The mid-UV (1700--2600 Angstroms) shows additional emission lines, particularly [C II] and [Si II] in the 2325 Angstroms region; the photospheric continuum rises strongly toward the longer wavelengths. The 2600--2850 Angstroms interval is mostly a photospheric absorption spectrum, although the bright chromospheric emission doublet of Mg II lords over the 2800 Angstroms region. We present a comprehensive spectral atlas based on our reductions of the STIS echellograms. We discuss the processing strategies, line identifications, and some of the preliminary results from our analysis of this windy, noncoronal giant. (1) This work was supported by grants GO-06066.01-94A from STScI, and NAG5-3226 from NASA. Observations were from the NASA/ESA HST, collected at the STScI, operated by AURA, under contract NAS5-26555. Title: A Search for Microflaring Activity on DME Flare Stars. II. Observations of YZ Canis Minoris Authors: Robinson, R. D.; Carpenter, K. G.; Percival, J. W. Bibcode: 1999ApJ...516..916R Altcode: We report on time-series photometric observations of the dM4.5e flare star YZ Canis Minoris obtained in 1993 November with the High Speed Photometer on board the Hubble Space Telescope. The data consist of five 30 minute time sequences with a sampling rate of 0.01 s that were taken through the F240W filter (centered at 240 nm with an 80 nm width). At these wavelengths the stellar photospheric background is small, so relatively small flares can be detected. The observations show a stellar background of 120 counts s-1 on which are superposed 54 flare events ranging in integrated flux from 2.0×1028 to 3.0×1030 ergs, as well as longer term variations with an amplitude of up to 50% of the average continuum intensity and timescales ranging from several minutes to hours. A statistical analysis of this background suggests that it may be composed of unresolved microflaring activity that has an energy distribution considerably steeper than that deduced for the larger flare events. This is consistent with previous observations as well as the self-organized criticality and reconnecting current sheet flare theories. These results are compared with data from the dM8e flare star CN Leonis, which was obtained earlier with the same experimental setup. CN Leo has both a smaller stellar background and a lower flare occurrence rate than YZ CMi. The fact that CN Leo also has a quiescent X-ray flux that is less than 10% of the YZ CMi emission suggests a link between chromospheric and coronal heating.

Based on observations with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Title: A Goddard High Resolution Spectrograph Atlas of Echelle Observations of the HGMN Star chi LUPI Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Proffitt, C. R.; Wahlgren, G. M.; Johansson, S. G.; Nilsson, H.; Brage, T.; Snow, M.; Ake, T. B. Bibcode: 1999AJ....117.1505B Altcode: Observations of the ultra-sharp-lined, chemically peculiar star chi Lupi taken by the Goddard High Resolution Spectrograph in echelle mode are presented. Thirty-six intervals of the spectral region between 1249 and 2688 Å are covered with resolving powers in the range 75,000-93,000. Line identifications are provided, and the observed spectra are compared with synthetic spectra calculated using the SYNTHE program and associated line lists with changes to the line lists. The significance of these spectra for the chi Lupi Pathfinder Project and the closely related atomic physics effort is discussed in a companion paper. Title: Lines of OIV and SIV in the Goddard High-Resolution Spectrograph spectrum of RR Tel: constraints on atomic data Authors: Harper, G. M.; Jordan, C.; Judge, P. G.; Robinson, R. D.; Carpenter, K. G.; Brage, T. Bibcode: 1999MNRAS.303L..41H Altcode: High signal-to-noise ratio spectra of RR Tel obtained at medium resolution with the Goddard High-Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST) are used to test available atomic data for the OIV 2s^22p ^2P-2s2p^2 ^4P multiplet (UV 0.01). The fine-structure intervals of the 2s2p^2 ^4P term given by Moore (1983) appear to need revision. The flux ratios of lines within multiplet UV (0.01), which have a common upper level, depend only on transition probabilities. The observed flux ratio of lines from the ^4P_3/2 level differs from that predicted by theory, but this difference cannot be attributed to a blend with a line of SIV]. At the electron densities in the RR Tel nebula, other flux ratios give information on the relative electron excitation rates between the ^2P and ^4P fine-structure levels. Using the collision strengths calculated by Zhang, Graziani & Pradhan, the rate to the ^4P_5/2 level, relative to the rates to the other J states, appears to be underestimated by ~ 10 per cent, which is within the expected uncertainty of 20 per cent. We also discuss the SIV 3s^23p ^2P-3s3p^2 ^4P multiplet. Title: Echelle Spectroscopy of Interstellar Absorption toward MU Columbae with the Goddard High Resolution Spectrograph Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Howk, J. C.; Snow, M.; Ake, T. B.; Sembach, K. R. Bibcode: 1999AJ....117..400B Altcode: Goddard High Resolution Spectrograph echelle-mode observations of the interstellar absorption lines of Mg II, Si IV, C IV, and N V toward mu Columbae (HD 38666) are presented. The observations have a spectral resolution of 3.5 km s^-1 and signal-to-noise ratios (S/Ns) of 20-200. The mu Col sight line (l=237.3d, b=-27.1d, d=0.40 kpc, z=-0.18 kpc) extends though the Local Bubble and the warm neutral, warm ionized, and hot ionized phases of the interstellar medium (ISM). The high-ionization column densities toward mu Col are log N(Si IV)=12.16+/-0.05, log N(C IV)=12.88+/-0.02, and logN(N V)=11.8-12.3. Profile fits to Copernicus satellite measures of O VI absorption toward mu Col yield log N(O VI)=13.82+/-0.01 and b=38.7 km s^-1. This implies N(C IV)/N(O VI)=0.11+/-0.01, which is typical of the values found for the hot ISM of the Galactic disk. The O VI profile is twice as broad as the C IV and N V profiles, even though these species have roughly similar average velocities. Some of the C IV, N V, and O VI absorption toward mu Col may occur at the interface of the Local Cloud and Local Bubble, although additional contributions to these ions probably also occur in more distant gas along the sight line. A substantial part of the Si IV absorption likely arises in warm photoionized gas in an H II region surrounding mu Col. The profile width differences among the high-ionization lines of C IV, N V, and O VI could be produced if the line of sight passes through a highly evolved supernova remnant. The observations for mu Col and for other stars observed at high resolution with the GHRS reveal that multiple gas types (warm and hot) contribute to the absorption by the highly ionized atoms along both nearby and distant sight lines. Disentangling the relative contributions from the different gas types requires high-resolution and high-S/N observations. The Mg II observations, combined with a solar Mg reference abundance, imply that the Mg depletion toward mu Col is -0.31 dex. As observed for other sight lines through the warm neutral medium, the gas-phase observations of Mg, when combined with results for Fe and Si, suggest that Mg and Fe are more deficient from the gas phase than one would expect if these elements are only contained in silicate dust grains. Title: Winds and mass-loss from evolved, low-gravity cool stars. Authors: Carpenter, Kenneth G.; Robinson, Richard D. Bibcode: 1999NewAR..43..471C Altcode: We summarize results from several programs utilizing the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST) to study winds and mass-loss from evolved, low-gravity cool stars. We have found that: (i) the photons for thermally and fluorescently excited UV emission lines are created below the region of wind acceleration, (ii) the self-reversals in optically thick emission lines indicate an outflowing wind with mean velocities of 9-25 km/s, (iii) the profiles of optically thin emission lines indicate a mean chromospheric macroturbulence of 24-35 km/s, anisotropically distributed along the radial-tangential directions, (iv) significant emission from hot material (≈10 5 K) is seen in both non-coronal and hybrid stars to the right of the Linsky-Haisch dividing line, (v) the weakness of Fe II emission lines in the carbon stars, combined with the presence of the Fe I 2807 Å feature only in carbon stars, suggests that the ionization fraction of iron is significantly lower in the outer atmospheres of carbon stars than in O-rich stars, and (vi) Fe II line profile variations indicate changes in mass-loss rate and wind opacity on a timescale of several years in two typical late-type, low-gravity stars. Title: The outer atmosphere of Tau - II. Fluorescent lines Authors: McMurry, A. D.; Jordan, C.; Carpenter, K. G. Bibcode: 1999MNRAS.302...48M Altcode: The Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope has been used to observe α Tau (K5 III). The resulting spectra contain many sharp fluorescent lines. Most of these have been identified as lines of Fe ii, Ca ii and H2, radiatively excited by H Lyα. The chromospheric model developed in an accompanying paper has been used to calculate the fluxes in these lines. The Ca ii lines have been modelled with a full radiative transfer calculation, but the Fe ii and H2 systems are more complex and, for these, a simpler calculation has been made. Overall, the trend in the Fe ii line fluxes provides evidence for a multicomponent model of the atmosphere, a chromosphere with intrusions of hotter material or vice versa. The hotter material could be in shocks propagating through the chromosphere. Comparisons of the observed and calculated fluxes of individual lines of Fe ii show that some atomic data need to be improved. The analysis of the H2 lines is restricted by a lack of suitable molecular data. The two observed Ca ii lines are reproduced to within a factor of 2. Title: Estimation of Mass-Loss Rates from Emission Line Profiles in the UV Spectra of Cool Stars Authors: Carpenter, K. G.; Robinson, R. D.; Harper, G. M. Bibcode: 1999STIN...0027505C Altcode: The photon-scattering winds of cool, low-gravity stars (K-M giants and supergiants) produce absorption features in the strong chromospheric emission lines. This provides us with an opportunity to assess important parameters of the wind, including flow and turbulent velocities, the optical depth of the wind above the region of photon creation, and the star's mass-loss rate. We have used the Lamers et al. Sobolev with Exact Integration (SEI) radiative transfer code along with simple models of the outer atmospheric structure to compute synthetic line profiles for comparison with the observed line profiles. The SEI code has the advantage of being computationally fast and allows a great number of possible wind models to be examined. We therefore use it here to obtain initial first-order estimates of the wind parameters. More sophisticated, but more time-consuming and resource intensive calculations will be performed at a later date, using the SEI-deduced wind parameters as a starting point. A comparison of the profiles over a range of wind velocity laws, turbulence values, and line opacities allows us to constrain the wind parameters, and to estimate the mass-loss rates. We have applied this analysis technique (using lines of Mg II, 0 I, and Fe II) so far to four stars: the normal K5-giant alpha Tau, the hybrid K-giant gamma Dra, the K5 supergiant lambda Vel, and the M-giant gamma Cru. We present in this paper a description of the technique, including the assumptions which go into its use, an assessment of its robustness, and the results of our analysis. Title: The Chromosphere, Wind, and Mass-Loss Rate of lambda Velorum (K5 Ib) as Revealed by UV Emission Line Profiles Authors: Carpenter, K. G.; Robinson, R. D.; Harper, G. M.; Bennett, P. D.; Brown, A.; Mullan, D. J. Bibcode: 1998AAS...193.4502C Altcode: 1998BAAS...30Q1317C The Goddard High Resolution Spectrograph (GHRS) on the HST has been used to acquire high-quality UV spectra of the nearby K-supergiant lambda Velorum. These spectra contain a wide variety of chromospheric emission lines, many of which are self-reversed by wind absorption, and thus allow us to probe the structure of both the chromosphere and wind. The observed line widths, positions, and fluxes indicate a chromosphere with a mean log n_e ~ 8.9 +/- -0.2 cm(-3) , a turbulence (indicated by line cores with ~ 25 km s(-1) Doppler widths) greatly in excess of the photospheric value, and no general systematic flows (i.e. the wind acceleration appears to occur above the region of photon creation). We compare synthetic Fe II line profiles from the approximate Lamers et al. (1987) Sobelev with Exact Integration (SEI) method, and from an exact comoving frame CRD calculation, with the observations. The width and shape of the wind self-absorptions implies a terminal velocity of 29--33 km s(-1) , and a wind turbulence of ~ 9-21 km s(-1) . We find that the wind in the 1994 GHRS observations can be described by a model with an acceleration parameter beta ~ 0.9 and a mass-loss rate of ~ 3 x 10(-9) Msun yr(-1) . However, this model is not consistent with the VLA 3.6 cm radio continuum flux observed in 1997. Title: The Mass of the Cepheid Binary V636 Scorpii Authors: Böhm-Vitense, E.; Evans, N. R.; Carpenter, K.; Albrow, Michael D.; Cottrell, P. L.; Robinson, R.; Beck-Winchatz, B. Bibcode: 1998ApJ...505..903B Altcode: The mass-luminosity relation for Cepheids depends on the degree of mixing in their main-sequence progenitors. Masses of Cepheids can be inferred by using different aspects of pulsation theory. These methods have in the past led to diverging results, showing that something was wrong in either evolution theory or pulsation theory or both. For some binary Cepheids dynamical masses, which are independent of pulsation and evolution theories, can be determined. V636 Sco is one of a handful of Cepheid binaries whose companions are bright enough in the ultraviolet that orbital radial velocities can be measured. We have here attempted to determine the radial velocity of the companion V636 Sco B to the Cepheid V636 Sco A by means of two Hubble Space Telescope (HST) spectra taken at phases of minimum and maximum Cepheid orbital velocities. The ratio of the orbital velocity of the companion and the Cepheid (which is the inverse of their mass ratio) came out to be 1.25 +/- 0.17. V636 Sco B has a spectral type B9.5 V, for which we expect a stellar mass of 2.5 M⊙. For the Cepheid we thus determine a mass of 3.1 +/- 0.4 M⊙, which is surprisingly low. If true, such a low mass would indicate an extremely large amount of excess mixing, which is very unlikely.

We discuss the likely possibility that V636 Sco B may itself be a binary with an unseen secondary, in which case the mass derived from the two measurements discussed above is not correct. Although the error limits for the mass of each Cepheid are rather large, the combined mass-luminosity relation for all Cepheids studied by us so far by means of HST spectra indicates excess mixing corresponding to core convective overshoot by 0.25 to about 0.5 pressure scale height in the main-sequence progenitors of the Cepheids.

Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NASS-26555. Title: Toward a Mass for the High Luminosity Cepheid T MON Authors: Evans, Nancy Remage; Robinson, Richard D.; Carpenter, Kenneth G.; Vinko, Jozsef; Massa, Derck; Wahlgren, Glenn M. Bibcode: 1998AAS...192.8204E Altcode: 1998BAAS...30.1155E The long period (27(d) ) Cepheid T Mon was shown by Coulson (1983, MNRAS, 203, 925) to have orbital motion. A full orbit has not yet been observed since the first velocities nearly a century ago. However, the ratio of the orbital velocity changes during the last decade provide the mass ratio between the Cepheid and its hot companion. We have obtained new ground-based velocities of the Cepheid which constrain the orbital velocity amplitude. To measure the companion velocities, we have IUE high resolution spectra and also a Hubble Space Telescope Goddard High Resolution Spectrograph spectrum (1840 to 1880 Angstroms). Use of the new data to constrain the mass of the Cepheid will be discussed. Title: Goddard High-Resolution Spectrograph Observations of Cool Low-Gravity Stars. IV. A Comparison of the K5 III stars α Tauri and γ Draconis Authors: Robinson, Richard D.; Carpenter, Kenneth G.; Brown, Alexander Bibcode: 1998ApJ...503..396R Altcode: The Goddard High-Resolution Spectrograph (GHRS) has observed the K5 III star α Tau in the 2330 Å region on three separate occasions. These spectra show marked changes with time, with the UV continuum varying by a factor of 2, and with the emission lines changing in flux by 30% or more, with the amount of change dependent upon the opacity of the line. The variations suggests a restructuring of the atmosphere rather than simply a change in the surface area covered by chromospheric material. Surprisingly, there was no detectable change in the chromospheric turbulence on timescales of hours or years. On average, the lower part of the atmosphere was found to be fairly static, with a slight infall of 1-2 km s-1. At higher altitudes, probed by observation of the stronger Fe II lines as well as of the O I (UV 2) and Mg II (UV 1) resonance lines, there is evidence for the acceleration of a slow wind, similar to that seen in the M giants γ Cru and μ Gem. This wind is much less massive than for the later type giants, however, since its effects are seen in only the most optically thick of the Fe II lines. Comparison of the α Tau observations with similar data for the K5 III hybrid star γ Dra shows remarkable similarity in the photosphere and lower chromosphere. Both stars have pronounced UV continua, identical turbulences and chromospheric densities, and very similar line fluxes and profiles for all lines formed in the lower chromosphere, including C II], Co I, Si II], and Fe II. A deep exposure near 1500 Å also shows the first evidence for hot plasma in the atmosphere of α Tau through the detection of the C IV (UV 1) doublet with a surface flux about 30% of that observed in γ Dra. Most of the evidence for the stellar wind is in the Mg II (UV 1) and O I (UV 2) resonance lines. Modeling these lines using the Sobolev with Exact Integration (SEI) radiative transfer code shows that the wind in γ Dra accelerates faster and reaches a higher terminal velocity than does the wind in α Tau. However, the wind turbulent velocity in γ Dra is only about one-third of the value seen in α Tau. We conclude that the observations support the suggestion by Judge & Stencel that the processes that heat the chromosphere are distinct from those that drive the stellar winds.

Based on observations with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Title: An Ultraviolet Spectral Atlas of 10 Lacertae Obtained with the Goddard High Resolution Spectrograph on the Hubble Space Telescope Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Snow, M.; Ake, T. B.; Hogen, R. H. Bibcode: 1998AJ....116..941B Altcode: Observations of the narrow-lined O-type star 10 Lacertae taken with the Goddard High Resolution Spectrograph in 1992 November are presented. The spectra cover the wavelength range 1181-1777 Å with a resolution of 15 km s^-1 and signal-to-noise ratio greater than 100:1. Absorption lines arising in the interstellar medium, the photosphere, and the stellar wind are identified and discussed. Title: Large Variations in the Winds of Single Cool Giants: λ Velorum and γ Crucis Authors: Mullan, D. J.; Carpenter, K. G.; Robinson, R. D. Bibcode: 1998ApJ...495..927M Altcode: UV spectra of the ``noncoronal'' single K supergiant λ Vel and of the single M giant γ Cru obtained with IUE and the Hubble Space Telescope at various epochs indicate that the profiles of many lines formed in the wind exhibit striking alterations in shape with time. We parameterize the wind profiles in terms of an empirical optical depth τemp by reflecting the red wing about line center and comparing the reflected intensity with that of the blue wing. In the λ Vel wind the terminal velocity v∞ was found to be close to 40 km s-1 in 1978, 1982, and 1994, but was at least 20 km s-1 greater in 1990. The faster wind in 1990 also had a total optical depth that was a factor of 2-6 times greater than at the other epochs.

Based on observations with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555, and on observations with the International Ultraviolet Explorer. Title: Classical Cepheid Masses: U Aquilae Authors: Evans, Nancy Remage; Böhm-Vitense, Erika; Carpenter, Kenneth; Beck-Winchatz, Bernhard; Robinson, Richard Bibcode: 1998ApJ...494..768E Altcode: We have obtained medium-resolution spectra (λ/Δλ ~ 20,000) of the hot binary companion to the classical Cepheid U Aql with the Goddard High Resolution Spectrograph on the Hubble Space Telescope (HST). These have been used to determine the orbital velocity amplitude. Combining this with the orbital velocity amplitude of the Cepheid from the ground-based orbit and the mass of the companion inferred from its spectral type, we measure a mass of the Cepheid of 5.1 +/- 0.7 M⊙. We discuss the full sample of Cepheids for which we have determined masses with HST (S Mus, V350 Sgr, Y Car, and U Aql) and also SU Cyg (mass from IUE). The HST masses are in agreement with the luminosities predicted by recent evolutionary tracks with moderate overshoot. This comparison, however, may be altered by reassessment of Cepheid distances based on Hipparcos parallaxes.

Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NASA-26555. Title: On Chromospheric Heating Mechanisms of ``Basal Flux'' Stars Authors: Judge, P. G.; Carpenter, K. G. Bibcode: 1998ApJ...494..828J Altcode: Several pieces of evidence have been pieced together over recent years to support the notion that the chromospheric emission measured from stars with convection zones results in part from the upward propagation and dissipation of acoustic waves. One argument, based on a statistical analysis of available UV data of such stars across the H-R diagram, suggests the presence of an omnipresent ``basal'' level of chromospheric heating, which has been postulated as resulting from nonlinear acoustic wave heating.

However, with few exceptions, no studies have been made that test more directly the intrinsically dynamic nature of this shock-heating mechanism. Therefore, in order to search for more direct signatures of such upward-propagating shock waves in lines of C II, we examined Goddard High-Resolution Spectrograph spectra of several evolved stars that have ``basal'' levels of activity. No evidence is found to support the presence of such waves as a dominant component of the heating mechanism. Instead, behavior reminiscent of the solar transition region is seen, suggesting a magnetic heating mechanism for these stars.

We conclude that upward-propagating shock waves do not dominate the observed radiative losses from chromospheres of stars exhibiting typical ``basal'' behavior, and we suggest that the nonmagnetic origin of the basal components of all convective stars must be called into question. New solar data from the SUMER instrument on SOHO also suggest problems with the acoustic-wave interpretation, although further work is warranted.

In the course of this work, we also found a simple explanation for previously noted discrepancies between calculated and observed ratios of C II lines in the spectrum of α Ori.

Based on observations with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Title: The Goddard High Resolution Spectrograph: Post-COSTAR Characteristics Authors: Robinson, R. D.; Ake, T. B.; Lindler, D. J.; Heap, S. R.; Carpenter, K. G.; Leckrone, D. S.; Maran, S. P.; Smith, A. M.; Brandt, J. C.; Beaver, E. A.; Boggess, A.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Linsky, J. L.; Savage, B. D.; Trafton, L. M.; Walter, F. M.; Weymann, R. J. Bibcode: 1998PASP..110...68R Altcode: We review changes to the characteristics of the Goddard High Resolution Spectrograph (GHRS) which resulted from the installation of the Corrective Optics Space Telescope Axial Replacement (COSTAR) on the Hubble Space Telescope. The introduction of two new optical elements into the light path altered the spectral distribution of the light, decreasing the amount of light striking the instrument by about 30% at wavelengths greater than 1200 Å and effectively eliminated all radiation at wavelengths less than 1130 Å. However, at the longer wavelengths the improved focus offset this loss when the Large Science Aperture (LSA) was used and increased the overall throughput of the Small Science Aperture (SSA) by a factor of 2. The improved focus also enhanced the spectral resolution of LSA observations and improved the ability of the instrument to observe in crowded fields. Title: The Mass of the Classical Cepheid V350 SGR Authors: Evans, N. R.; Bohm-Vitense, E.; Beck-Winchatz, B.; Carpenter, K.; Robinson, R. Bibcode: 1998ASPC..143..313E Altcode: 1998sigh.conf..313E No abstract at ADS Title: The Structure of the Outer Atmosphere and Wind of lambda Vel Authors: Carpenter, Kenneth G. Bibcode: 1998IAUS..191P.206C Altcode: The Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST) has been used to acquire high-quality UV spectra of the nearby K-supergiant lambda Vel, a star most likely in an evolutionary stage either immediately preceeding or just entering the AGB. These spectra contain a wide variety of chromospheric emission lines, as well as a strong chromospheric continuum, and thus allow us to probe conditions in the the atmospheric region within which the stellar wind and associated mass-loss are initiated. In addition, the profiles of many of these emission lines are influenced by absorption occurring within the wind and are thus good diagnostics of the radial structure of that wind. Comparison of synthetic and observed spectra allows estimates of the wind turbulence, acceleration, opacity, and mass-loss rate. We present a summary of our analysis of these spectra, including: 1) measurements of temperature, turbulence, and flow velocity versus height in the chromosphere and wind, and 2) estimates of the mass-loss rate. It is our hope that these observations will provide powerfull constraints on theoretical models of chromospheric heating, wind acceleration, and mass-loss in this and other red giant and supergiant stars. Title: The Mass of the Beat Cepheid Y Carinae Authors: Bohm-Vitense, E.; Beck-Winchatz, B.; Evans, N. R.; Carpenter, K. G.; Robinson, R. Bibcode: 1998ASPC..143..317B Altcode: 1998sigh.conf..317B No abstract at ADS Title: Fluorescence in the Chromosphere of alpha Tau (K5 III) Authors: McMurry, A. D.; Jordan, C.; Carpenter, K. G.; Robinson, R. D. Bibcode: 1998ASPC..154.1293M Altcode: 1998csss...10.1293M The Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope has been used to obtain spectra of alpha Tau covering many parts of the uv spectrum between 1200AA and 2000AA. Here we concentrate on the region between 1320AA and 1390AA, which is covered by 2 medium resolution exposures. Most of the lines appearing in these spectra have been identified, including 2 bands of fluorescent CO lines. Preliminary modelling of these CO lines has been carried out, and the results are compared with the observations. Title: The Mass of the Classical Cepheid S MUSCAE Authors: Evans, N. R.; Bohm-Vitense, E.; Beck-Winchatz, B.; Carpenter, K.; Robinson, R. Bibcode: 1998ASPC..143..309E Altcode: 1998sigh.conf..309E No abstract at ADS Title: The Dynamical and Beat Masses of the Beat Cepheid Y Carinae Authors: Bohm-Vitense, E.; Evans, N. R.; Carpenter, K.; Winchatz, B. Beck-; Morgan, S.; Robinson, R. Bibcode: 1998ASPC..135..280B Altcode: 1998hcsp.conf..280B The mass-luminosity relation for Cepheids depends on the degree of excess mixing in their main sequence progenitors. The mass determination for Cepheids with their known luminosities therefore determines the degree of excess mixing in massive main sequence stars. We have determined the dynamical mass of several Cepheids with blue companions. Here we discuss the beat Cepheid Y Carinae. By means of HST, GHRS spectra we measured the radial velocity of the B9.5 V companion Y Car B at phases near minimum and maximum orbital radial velocities. The orbital velocity amplitude ratio between the Cepheid and the hot companion and thereby the mass ratio comes out to be 1.51 0.5, leading to a mass of 3.8 1 1.2 solar masses. Taking the 3.8 solar masses at face value this indicates excess mixing corresponding to convective overshoot by about 1 pressure scale height, (see Bertelli et al.1986), but the error limits are too large for a firm conclusion. The beat masses, determined from the period ratios for the beat Cepheids, have puzzled astronomers for a long time (see Cox 1980) because they came out around 1 to 2 solar masses, when the Cox-Tabor opacities were used for the model calculations. Moskalik et al.(1992) showed that beat masses around 4 to 5 solar masses can now be derived, if the new OPAL opacities are used instead. With the determination of the dynamical mass for Y Car A we can now check the validity of the OPAL opacities more quantitatively than was possible before. Using the model calculations incorporating the OPAL opacities, and the observed effective temperature of Y Carinae we determine for its beat mass a possible range of 3.75 < M/Ms < 4.0, in very good agreement with the dynamical mass. This supports the validity of the OPAL opacities, and also supports the conclusion about the high degree of excess mixing in the main sequence progenitor of Y Carinae A. Title: Cool Stars Authors: Carpenter, K. G. Bibcode: 1998ASPC..143...67C Altcode: 1998sigh.conf...67C No abstract at ADS Title: Winds and Mass-Loss from Evolved, Low-Gravity Cool Stars Authors: Carpenter, K. G.; Robinson, R. D. Bibcode: 1998HiA....11..378C Altcode: No abstract at ADS Title: Searching for the Cause of Hybrid Star Activity Authors: Robinson, Richard D.; Carpenter, Kenneth G.; Brown, Alexander Bibcode: 1998ASPC..154.1307R Altcode: 1998csss...10.1307R UV spectra for a wide range of chromospheric diagnostics have been obtained for the non-coronal giant alpha Tau and the `hybrid' star gamma Dra using the Goddard High Resolution Spectrograph. These stars have very similar spectral types and are very close to one another in mass, luminosity, size, effective temperature and gravity. A detailed comparison shows that the photosphere and chromosphere of the stars are very similar. The two stars show the same level of UV continuum emission and chromospheric turbulence and have Fe 2 emission profiles which are nearly identical. The amount of transition region plasma, as measured by the C 4 surface flux, is also nearly the same. The winds of these two stars, however, are significantly different. Preliminary models based on the O 1 (UV 2) and Mg 2 (UV 1) profiles show that the wind for alpha Tau has a terminal velocity of ~30 km s^{-1} and a much slower acceleration than the wind of gamma Dra, which has a terminal velocity of ~65 km s^{-1}. However, despite the different wind properties, the mass loss rate from these two stars is very similar. Title: Two-Component Winds from Luminous Late-Type Stars Authors: Airapetian, V. S.; Offman, L.; Robinson, R.; Carpenter, K.; Davila, J. Bibcode: 1998BAAS...30..760A Altcode: We present the results of a magnetohydrodynamic (MHD) simulation of winds from luminous late-type stars using a 2.5D, non-linear MHD computer code. In this simulation we assume that the wind is generated within a hydrostatic atmosphere with an initial isothermal pressure scale height of 0.072 Rstar and a radial magnetic field. We also assume a transverse density gradient which we we refer to as a ``chromospheric hole''. Tortional Alfven waves are generated at the stellar surface by a forcing function having a single frequency, which is comparable to the turn-over frequency of convective cells in giant stars. To ensure that we are accurately assessing the terminal velocity of the wind, we carried out the calculations to a height of 20 stellar radii and a time period of more than 180 Alfven transit times, which ensures that a steady state has been reached. In the higher density (low Alfven velocity) regions outside of the ``chromospheric hole'' the Alfven waves are freely propagating. Ponderomotive forces associated with these waves drive radial, compressive motions and contribute to stellar wind acceleration. The compressive motions then excite slow magnetosonic waves which non-linearly steepen into solitary waves that propagate on top of a background flow similar to the case of solar coronal holes. This produces a fast (40-80 km/s) and relatively dense component of the wind. In the lower density ``chromospheric hole'' region the Alfven waves are strongly reflected and produce an outflow with both radial and azimuthal velocities which are ~ 10% of the local Alfven speed. This component of the wind is slow ( ~ 10-30 km/s) and less dense than the wind initiated outside of the hole. Depending on the magnetic topology in the atmosphere of a luminous late - type star, we may therefore expect either one (fast) or two components to the wind. Our results are consistent with recent observations of two discrete components to the wind in the K5 III hybrid star gamma Dra. These components were detected in the Mg II h and k resonance lines and had velocities of 67 and 30 km/s, with the higher velocity component having a mass loss rate which is 10 times that of the slower speed wind. Title: Atmospheric Dynamics of Luminous Late-Type Stars Authors: Airapetian, V. S.; Ofman, L.; Robinson, R. D.; Carpenter, K.; Davila, J. Bibcode: 1998ASPC..154.1569A Altcode: 1998csss...10.1569A We present first results of magnetohydrodynamic (MHD) calculations of winds from luminous late-type stars using an existing, 2.5D, non-linear MHD code recently developed by Ofman & Davila (e.g., Ofman & Davila 1997). We assume that the wind is initiated in a hydrostatic atmosphere with an isothermal pressure scale height of 0.072 R* and a ``chromospheric hole'' modeled by a transverse density structure and a radial magnetic field. To ensure that we are accurately assessing the terminal velocity of the wind, we carried out the calculations to a height of 20 stellar radii. We find that in the higher density (low Alfven velocity) regions outside of the ``chromospheric hole'' the Alfven waves are freely propagating. Ponderomotive forces associated with these waves drive radial, compressive motions and contribute to stellar wind acceleration. The compressive motions then excite slow magnetosonic waves which non-linearly steepen into solitary waves that propagate on top of a background flow. This situation is similar to solar coronal hole models. In the lower density ``chromospheric hole'' region the Alfven wave are strongly reflected, and produce a substantial outflow, with both radial and azimuthal velocities approaching the local Alfven speed. Our results are in qualitative agreement with observational signatures of winds in cool, luminous late-type stars. Title: HST Observations of Carbon Stars Authors: Carpenter, Kenneth G.; Robinson, R. D.; Johnson, H. R. Bibcode: 1998ASPC..154.1578C Altcode: 1998csss...10.1578C Ultraviolet spectra obtained with the Goddard High Resolution Spectrograph (GHRS) on the HST of the carbon stars TX Psc, TW Hor, and UU Aur are presented and compared with each other and with spectra of the oxygen-rich cool giants mu Gem and 30 Her. For TX Psc, we discuss the inferred outer atmospheric flow and turbulent velocities, the relative and absolute strength of emission from C 2 and Fe 2, the ionization fraction of iron, and variations of its spectrum with time. We also discuss two fluorescence processes operating in the atmospheres of carbon stars and compare in detail the Mg 2 profiles seen in both carbon and O-rich stars. Title: Digging Deeper in the Coronal Graveyard Authors: Ayres, Thomas R.; Brown, Alexander; Harper, G. M.; Bennett, P. D.; Linsky, J. L.; Carpenter, K. G.; Robinson, R. D. Bibcode: 1997ApJ...491..876A Altcode: Soft X-ray detections of stellar coronae (T ~ 106 K) are rare in the giant branch redward of ~K1 III. We have conducted a less direct--but more sensitive--search using the Hubble Space Telescope Goddard High-Resolution Spectrograph to probe for far-ultraviolet proxies of the hot coronal gas in representative ``noncoronal'' red giants. In every target so far examined, we find weak but statistically significant Si IV emission, as well as, commonly, C IV and, in some cases, N V. Si IV is not affected by the CNO anomalies produced by the first dredge-up, which can deplete the carbon abundance and weaken C IV. In the low-activity giants, the λ1393 component of the Si IV doublet must be corrected for sharp absorptions, which we believe are caused by carbon monoxide in overlying cool material.

The normalized flux ratios (\Rscr≡f/fbol) of Si IV and X-rays among the ``coronal'' yellow giants (lying just blueward of the ``noncoronal'' zone) fall on a uniform track, \RscrX~\Rscr2SiIV. In the noncoronal zone, however, the Si IV index is nearly constant (\RscrSiIV~10-8), independent of \RscrX (which ranges from ~10-8 to <~10-10). The mechanism that diminishes X-ray activity in the red giants is highly sensitive to an as yet unidentified stellar property. Photoelectric absorption by cool gas might play a more important role than previously suspected, particularly if hot magnetic loops are partly or completely buried in the chromosphere. Title: Pondering Puzzling Profiles: MG II Emission from Carbon Stars Authors: Carpenter, K. G.; Robinson, R. D.; Johnson, H. R. Bibcode: 1997AAS...191.1306C Altcode: 1997BAAS...29.1230C We have obtained spectroscopic observations of the Mg II h & k emission lines from three carbon stars, using the moderate resolution (R>=20,000) G270M grating of the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST). The emission profiles from all three stars are very broad and heavily mutilated by overlying absorption. The profiles from two of the stars, TX Psc (N0; C6,2) and TW Hor (N0; C7,2), are very similar. However, the profiles from the third star, UU Aur (N3; C5,3) are dramatically different from the other two stars on the blue side, with strong emission persisting out to ~ -200 km/s (cf. to only weak emission out to ~ -100 km/s in TX Psc and TW Hor). If the intrinsic (i.e. chromospheric) width of the emission in the carbon stars is comparable to that in oxygen-rich giants, then the spectra of the first two carbon stars are easily understood in terms of additional overlying absorptions, but the amount of excess emission from the blue side of the UU Aur profiles is difficult to explain. If, on the other hand, the intrinsic width of the Mg II emission in the carbon stars is more comparable to that of the supergiant oxygen-rich stars (e.g. alpha Ori), then all the carbon stars have tremendous overlying absorption on both the blue and red wings of the profiles and UU Aur is notable only because it has significantly less absorption on the blue-side of the profiles, relative to the other carbon stars. In this paper, we present an analysis of the spectra and our interpretation, based on all the available data, of these fascinating and complex line profiles and their formation. Title: Hubble Space Telescope Spectroscopy of the Carbon Star TX Piscium Authors: Carpenter, Kenneth G.; Robinson, Richard D.; Johnson, Hollis R.; Eriksson, Kjell; Gustafsson, Bengt; Pijpers, Frank P.; Querci, Francois; Querci, Monique Bibcode: 1997ApJ...486..457C Altcode: Ultraviolet spectra obtained with the Hubble Space Telescope of the carbon star TX Piscium (HR 9004) are presented, along with analysis providing information on its outer atmosphere, including flow and turbulent velocities, line formation mechanisms, and variations with time. Both thermal (collisionally excited) and fluorescent emission from the chromosphere of the star appear to be formed near the stellar rest velocity, i.e., in a region below that in which the stellar wind is accelerated. Absorption self-reversals in the Mg II emission confirm the presence of an outflowing stellar wind at a mean velocity of about 9-10 km s-1. Circumstellar absorption features (Mn I and Fe I) overlying the Mg II emission indicate a cool shell expanding at about 5-6 km s-1 relative to the photosphere. The widths (FWHM) of various emission lines indicate that the chromospheric turbulence is at least 16 km s-1, but that it may increase with altitude to as much as 34 km s-1. Three hours of integration on the C II] lines are examined for any signs of variability that might indicate the presence of shocks, but no statistically significant variations are seen. A previous identification (in spectra of UU Aur) of an emission line at 2807 Å, seen only in spectra of carbon stars, as belonging to Fe I multiplet UV45 pumped by the C II] line at 2325 Å is confirmed by the discovery of an absorption feature corresponding exactly to the wavelength of the pumped transition (Fe I UV13) near 2325 Å. Lines from Fe II UV165, previously seen in solar off-limb spectra and in Goddard High-Resolution Spectrograph spectra of α Tau, are clearly present. The normally much stronger Fe II UV32, 62, and 63 multiplets are seen but are weaker relative to both the UV165 lines and the intercombination lines of C II] and Si II] than in α Tau. The weakness of these Fe II lines is indicated both by their absolute flux levels and by their narrow, single-peaked profiles, which are in sharp contrast to the broad, double-peaked profiles seen in oxygen-rich cool giant and supergiant stars. The weakness of the Fe II lines and the presence of the Fe I 2807 Å line suggest that the ionization fraction of iron (Fe II/Fe I) is significantly lower in the outer atmospheres of carbon stars. Fluxes in emission lines of Fe II and Mg II are >=2-3 times lower than in a 1984 IUE spectrum of TX Psc, confirming that the latter was obtained at an epoch of unusual UV brightness for the star. The Mg II profiles are heavily mutilated by overlying absorption, even more so than in 1984. The TX Psc profiles are very similar to those seen in the carbon star TW Hor but are dramatically different than those in another carbon star, UU Aur, whose lines show violet wing emission out to much shorter wavelengths than in the other two stars.

Based on observations with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555 and on observations at the Haute-Provence Observatory. Title: The dynamical mass of the beat cepheid Y carinae and stellar opacities. Authors: Bohm-Vitense, E.; Evans, N. R.; Carpenter, K.; Morgan, S.; Beck-Winchatz, B.; Robinson, R. Bibcode: 1997AJ....114.1176B Altcode: The beat Cepheid, Y Carinae A, has a B9 V companion, Y Car B. The primary period P0 of the Cepheid is 3.64 days and the secondary, P1, is 2.56 days. Its period ratio P1/P0 is thus 0.703. Y Car is the only beat Cepheid known to be a binary and thus offers us the unique opportunity to determine the dynamical mass for a beat Cepheid. We have determined its mass by measuring the orbital velocity amplitude of the hot companion Y Car B using the Goddard High-Resolution Spectrograph (GHRS) with the G200M grating on the Hubble Space Telescope. When combined with the ground-based orbital velocity amplitude of the Cepheid and the mass of the companion, the implied mass of the Cephieid is M=3.8±1.2Msun. With the Cepheid luminosity given by the period-luminosity relation, this mass, taken at face value, indicates excess mixing in the main sequence progenitor corresponding to convective overshoot by about 0.9 pressure scale height, however, the large error bars prevent a firm conclusion. As shown by Simon the period ratio for beat Cepheids depends sensitively on the opacities. For models calculated with Cox-Tabor opacities the period ratios for beat Cepheids indicate masses between one and two Msun. Models calculated with the new Livermore OPAL opacities on the other hand indicate masses around 4 solar masses. The good agreement of the beat mass with the dynamical mass, determined here for Y Car, provides a confirmation that the OPAL opacities are a significant improvement over the Cox-Tabor (1976) opacities. Title: Observations of 3C273 with the Goddard High Resolution Spectrograph on the Hubble Space Telescope. II. Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Snow, M.; Randall, C. E.; Tripp, T. M.; Ake, T. B.; Crenshaw, D. M.; Bruhweiler, F. C. Bibcode: 1997AJ....114..554B Altcode: Observations of the quasar 3C 273 taken with the Goddard High Resolution Spectrograph in November and December 1993 are presented here. We have included both the fully-reduced spectra, and spectra combined with our earlier (1991) observations. There are a total of 10 new medium resolution exposures covering four wavelength regions: 1164-1201 Angstroms, 1214-1251 Angstroms, 1537-1573 Angstroms, and 1633-1670 Angstroms. We confirm the suggestion of Morris et al. (1991) that the galactic Si IV lambda 1393 line is blended with an extragalactic lya line by observing the lyb counterpart to this extragalactic line. We obtain an improved upper limit on the C IV/H I ratio in these weak low redshift lya absorption systems by coadding the corresponding C IV spectral regions. Improved line profiles for the galactic C IV and N V absorption are also presented and discussed. The improved measurements lead to a downward revision of the galactic C IV column density, log N (C IV) = 14.46+/- 0.04. Title: The Outer Atmospheres of Cool, Low Gravity Stars as Revealed by HST Authors: Carpenter, Kenneth G. Bibcode: 1997BaltA...6...73C Altcode: 1997OAst....6...73C We have used the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST) to measure the macroturbulent and flow velocities, the acceleration of winds, and the amount of hot (transition-region) plasma in the outer atmospheres of Carbon and K - M Giant/Supergiant stars. We see the acceleration of the stellar winds in the chromospheres of several of these stars from initial velocities of 3 - 9 km/s to upper velocities of 15 - 25 km/s and measured chromospheric macroturbulences ranging from approximately 25 to 35 km/s. We have found in the non-coronal giant alfa Tau weak C IV emission indicative of hot transition-region plasma, many new fluorescent lines of Fe II, and fluorescent molecular hydrogen emission and Ca II recombination lines seen for the first time in a giant star. Title: The Mass of the Classical Cepheid V350 SGR Authors: Evans, N. R.; Bohm-Vitense, E.; Carpenter, K.; Beck-Winchatz, B.; Robinson, R. Bibcode: 1997PASP..109..789E Altcode: Two medium resolution spectra of the hot companion of the Cepheid V350 Sgr have been obtained with the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope. Comparison of these spectra (in the wavelength range 1840 to 1880 \AA) with the spectrum of $\alpha$ Lyr shows that V350 Sgr B has a projected rotation velocity which may be as high as 150 km sec$^{-1}$. The velocity difference between the spectra of V350 Sgr B at two orbital phases is measured to be -23.1 $\pm$ 3.8 km sec$^{-1}$. The error is dominated by the aperture centering. When combined with the orbital velocity variation of the Cepheid derived from the ground-based orbit and the mass of the companion deduced from IUE spectra, the mass of the Cepheid is found to be 5.2 $\pm$ 0.9 M$\sun$. The observed mass--luminosity combination of V350 Sgr A is a good match to recent evolutionary calculations which use moderate convective overshoot near the main sequence, however, the blue loops do not extend to temperatures as hot as the Cepheid. (SECTION: Stars) Title: GHRS Observations of Cool Low-Gravity Stars. III. Plasma Flows and Turbulence in the Outer Atmosphere of α Orionis (M2 Iab) Authors: Carpenter, Kenneth G.; Robinson, Richard D. Bibcode: 1997ApJ...479..970C Altcode: We present the results of a Goddard High Resolution Spectrograph (GHRS) study of flow and turbulent velocities in the outer atmosphere of the M2 Iab supergiant α Ori. Ions with observed chromospheric emission features include C I, C II, Si I, Si II, O I, Co II, Al II, Mg II, Cr II, Fe I, and Fe II, while the photospheric absorption spectrum is dominated by Fe I. The widths of optically thin lines of C II], Si II], Co II, and Fe II indicate an average chromospheric turbulent velocity (Doppler FWHM) in the range of 31-35 km s-1, which is substantially above the expected chromospheric sound velocity. The shape of the C II] profiles indicates that this turbulence is probably anisotropically distributed, with velocities preferentially directed along and/or perpendicular to the radial direction. The radial velocity of near-UV Fe I photospheric absorption lines averaged 18 km s-1, somewhat smaller than the systemic RV of α Ori itself (21 km s-1) and significantly smaller than the RV of the optical Fe I lines (23 km s-1) at the time of the HST observations. The various components of the chromospheric emission lines had radial velocities in the range 7-36 km s-1. The emission wings for most of the ionic species averaged ~20 km s-1, i.e., they were nominally at rest with regard to the star. The central absorption features in these lines, however, showed lower velocities, averaging ~16 km s-1. The radial velocity of the central reversals in the stronger lines was also found to be correlated with the opacity of the lines, changing from ~20 km s-1 for the lower opacity lines to ~14 km s-1 for the higher opacity lines. This implies that we are directly viewing the acceleration of the stellar wind in the chromosphere from rest to about 7 km s-1. Contrary to the results reported earlier by Carpenter (1984) on the basis of IUE data, there is no indication of a deceleration of the wind at large distances from the star. Title: The Mass of the Classical Cepheid S Muscae Authors: Böhm-Vitense, Erika; Remage Evans, Nancy; Carpenter, Kenneth; Beck-Winchatz, Bernhard; Robinson, Richard Bibcode: 1997ApJ...477..916B Altcode: A good determination of the mass-luminosity relation for evolved stars on blue loops can determine the degree of excess mixing in the interiors of their main-sequence companions. In this study we determine the dynamical mass of the Cepheid binary S Muscae. This can be combined with its known luminosity and be fitted on evolutionary tracks to determine the amount of mixing in the main-sequence progenitor.

Using the Goddard High Resolution Spectrograph on the Hubble Space Telescope we have measured the orbital radial velocity changes for the companion of the Cepheid S Mus. Spectra taken at minimum and maximum orbital velocities were cross-correlated. The velocity difference was measured to be 30.6 +/- 0.4 km s-1. The difference for the orbital velocities of the Cepheid for the same phases was determined to be 26.9 km s-1 +/- 0.4 km s-1. This gives a velocity ratio of 1.14 +/- 0.02, which gives us the mass ratio for the companions. Adding possible centering errors of the target in the entrance apertures the error limit would be increased to +/-0.06.

The derived spectral types of the companion S Mus B range from B3 V to B5 V depending on the criterion used to determine it, with an average spectral type B3.8 V. Using the average spectral type and the main-sequence mass-spectral type relation from Andersen & Harmanec we find for S Mus B a mass of 5.2 +/- 0.2 M⊙. With the newly determined mass ratio the mass for the Cepheid S Mus A comes out to be 5.9+0.7-0.6 M⊙.

Taking the mass of 5.9 M⊙ at face value and adopting the absolute visual magnitude of Mv = -4.29 (log L/L⊙ = 3.62) for the Cepheid S Mus this indicates mixing in its main-sequence progenitor slightly in excess of the one assumed for the Maeder and Meynet evolutionary tracks. The present uncertainties in mass and luminosity prevent, however, a firm conclusion about the exact degree of mixing.

Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA Contract No. NASS-26555. Title: Winds and Mass-Loss from Evolved, Low-Gravity Cool Stars Authors: Carpenter, K.; Robinson, R. Bibcode: 1997IAUJD...8E..28C Altcode: The character of the winds and the amount of mass-loss from stars during the red giant and supergiant stage of evolution are critical to the progression of that evolution. We therefore summarize here the results of a series of programs utilizing the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST) to study the winds and mass-loss from the surface of evolved, low-gravity cool stars. We discuss the structure of the chromospheres in which the base of these stellar winds lie, the velocity of the wind and its acceleration with height, and what these spectra tell us about the mass-loss from these stars. Because of its relevance to this Joint Discussion, we will also discuss in some detail what we have learned about real-time variability of these phenomena and the implied somewhat erratic nature of the mass-loss process in at least some of these stars. Title: Fishing in the Coronal Graveyard Authors: Ayres, T. R.; Brown, A.; Harper, G. M.; Bennett, P. D.; Linsky, J. L.; Carpenter, K. G.; Robinson, R. D. Bibcode: 1996AAS...189.7815A Altcode: 1996BAAS...28.1379A Hot coronae (T ~ 10(6) K) are thought to be rare among single giant stars to the right of the ``Linsky--Haisch dividing line'' near K0 in the H--R diagram. K and M giants are such slow rotators that absence of dynamo generated magnetic activity would be natural. Nevertheless, gamma Dra (K5 III) unexpectedly was detected in FUV coronal proxies---hot lines Si IV lambda 1393 and C IV lambda 1548---by HST /GHRS during Science Verification, and subsequently was discovered as a faint X-ray source in a deep ROSAT /PSPC pointing. Is gamma Dra anomalous, or is the lack of coronal detections among the K giants simply a matter of insufficient sensitivity? We have used the GHRS low resolution mode to search for additional examples of hot lines among inactive single red giants. Si IV provides a clean diagnostic of subcoronal material because it falls near the peak sensitivity of the G140L mode and does not suffer from abundance depletions that can affect C IV in red giants. X-ray/Si IV ratios are such that HST can reach to much fainter limiting ``coronal'' magnitudes than even very deep ROSAT pointings. In every target so far examined, we find weak---but statistically significant---Si IV emission. These include: the ancient red giant Arcturus (alpha Boo: K1 III), recorded at the end of Cycle 5; and epsilon Crv (K2.5 III) and epsilon Sco (K2 III) observed in Cycle 6. X-ray/Si IV ratios of red giants (for which measurements, or upper limits, of both diagnostics are available) fall on a uniform track, extending downward from active K0 ``Clump'' giants like beta Ceti all the way to Arcturus itself, in the depths of the ``coronal graveyard.'' The systematic behavior argues that magnetic dynamo action continues even when long term angular momentum loss has slowed the stellar spin to a crawl. This work was supported by grant GO-06066.01-94A from STScI. Title: New Results on Cepheid Masses Authors: Evans, N. R.; Bohm-Vitense, E.; Carpenter, K.; Robinson, R.; Beck-Winchatz, B. Bibcode: 1996AAS...189.9608E Altcode: 1996BAAS...28.1399E Masses for Cepheid variable stars can be measured by combining the orbital velocity amplitude for the Cepheid (from a ground-based orbit) with the orbital velocity amplitude of a hot main sequence companion (observed in the ultraviolet from satellites such as IUE and HST) and the mass of the companion (inferred from from the ultraviolet energy distribution). Observations of 5 binary systems are now completed or in progress with the Goddard High Resolution Spectrograph on the Hubble Space Telescope. Recently completed observations of U Aql lead to a mass of 5.1 +/- 1.1 Msun . We will discuss the results for S Mus, V350 Sgr, U Aql, and Y Car, and the constraints they place on stellar evolution calculations. As would be expected, some of the B companions have high rotational velocities, decreasing the accuracy with which their orbital velocities can be measured. The preliminary conclusion from the 4 HST targets and SU Cyg (mass from IUE observations) is that a weighted mean indicates no convective overshoot but the mode (which reflects the HST results better) agrees with the modest overshoot used in the Geneva evolutionary calculations. Financial Support was provided by a NASA grant GO-4541-01 to EB--V and GO-4541.02 to KGC, a grant from the Natural Sciences and Engineering Council, Canada to NRE, from the AXAF Science Center NASA Contract NAS8-39073. Title: Observing Stellar Coronae with the Goddard High Resolution Spectrograph. II. The RS CVn Binary System HR 1099 Authors: Robinson, R. D.; Airapetian, V. S.; Maran, S. P.; Carpenter, K. G. Bibcode: 1996ApJ...469..872R Altcode: We report time series observations of the RS CVn star HR 1099 taken with the Goddard High Resolution Spectrograph onboard the Hubble Space Telescope. The data cover a wavelength range from 1342 to 1375 Å and show a measurable continuum, as well as emission lines of O I, C I, CII, Fe II, O V, and Fe XXI. The chromospheric and transition region features are seen only in the active K1 IV component of the binary system, while the Fe XXI (1O7 K) flux may come from both components, with the active component having the stronger flux. There is no indication of Fe MI emission, formed at 1.3 x 106 K. The width of the Fe XXI profile indicates that the corona of the primary is unlikely to extend to heights greater than 2.3R⋆, while other indicators suggest that the average loops are really much smaller, having a length of ∼3 x 1010 cm with an electron density on the order of 1010 cm-3. Some evidence for atmospheric turbulence is detected in all of the observed emission lines. This turbulence initially increases with height, going from less than 30 km s-1 in the chromosphere to as much as 150 km s-1 in the transition region. The turbulence then decreases in the corona, where velocities of less than 65 km s-1 are indicated. Theoretical fits to the O V profile also suggest that this turbulence is anisotropically distributed, with motions directed primarily along or perpendicular to the radial direction. While admitting the possibility that the atmosphere is heated by microflare events, we examine an alternative heating process that involves the damping of MHD turbulence, which might be generated by nonlinear Alfvén waves or by shocks. Simple calculations indicate that the observed turbulence is sufficient to account for the transition region and coronal heating. Title: UV Emission from the Atmosphere of Jupiter After the S-Impact of Comet SL9 Authors: Carpenter, K. G.; McGrath, M. A.; Yelle, R. V. Bibcode: 1996DPS....28.2247C Altcode: 1996BAAS...28.1150C The Hubble Space Telescope Faint Object Spectrograph was used to obtain a UV spectrum of the impact site of the S-fragment of comet SL9 approximately 45 minutes after the entry of the fragment into the atmosphere of Jupiter. This spectrum contains ultraviolet emission lines of neutral and ionized metals, including Mg I, Mg II, Fe I, Fe II, and Si I. Initial analyses of these data were presented by Noll et al. (1995, Science, 267, 1307) based on a pure solar resonance fluoresence synthetic spectrum and assuming collisional excitation at 1000 K, and by Carpenter et al. (DPS, Oct. 1995) who added non-resonance fluorescence and examined the possibility that some of the emission was caused by thermal excitation of metastable levels during the fireball and splashback phases of the impact. Since these line formation models do not fully account for the observed relative and absolute line fluxes, we have enhanced our model to include non-LTE effects, heating of the atmosphere due to infalling gas and dust, and the effects of multiple scatterings of photons as they attempt to exit the atmosphere of Jupiter at frequencies within optically thick lines. We compare the synthetic spectrum produced with this model to the observed spectrum and discuss the physical conditions and elemental abundances inferred from this comparison. Title: High Signal-to-Noise Ratio Observations of Weak Interstellar Absorption Lines Towards XI Ophiuchi With the Goddard High-Resolution Spectrograph Aboard the Hubble Space Telescope Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Hogen, R.; Snow, M.; Cardelli, J. A.; Ake, T. B.; Bruhweiler, F. Bibcode: 1996AJ....112.1128B Altcode: We present an atlas and tabulation of weak interstellar absorption lines in the ultraviolet spectrum of ζ Ophiuchi in four selected wavelength regions observed with the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope. The signal-to-noise ratio ranges from 150 to nearly 400, and the spectral resolving power exceeds 20 000, allowing 2σ detections of features as weak as Wλ=0.8 mÅ. We report positive measurements of two lines of OH, and weak detections of P I, Tl II, and N V. Upper limits of Wλ<1 mÅ are found for the molecules H2O, HCl, SiO, NO+, and CH2. Similar limits are found for heavy elements Te II, Co II, and Sb II. Three lines are present in our spectrum for which we have no identifications. They are found at wavelengths of λ=1229.84, 1313.98, and 1314.23 Å. However, none of the features reported by previous authors as unidentified absorption lines in the wavelength regions we have observed are present in our data. Title: Hubble Space Telescope Observations of the Seyfert Galaxy NGC 3783: Discovery of Variable C IV Absorption Authors: Maran, Stephen P.; Crenshaw, D. Michael; Mushotzky, Richard F.; Reichert, Gail A.; Carpenter, Kenneth G.; Smith, Andrew M.; Hutchings, John B.; Weymann, Ray J. Bibcode: 1996ApJ...465..733M Altcode: We have discovered variable absorption lines in HST spectra of the Seyfert 1 galaxy NGC 3783. C IV λλ1548.2, 1550.8 absorption is present in an FOS spectrum on 1992 July 27 and a GHRS spectrum on 1994 January 16 at a radial velocity of -450 km s^-1^ relative to the emission-line peak, but there is no evidence for absorption in a GHRS spectrum on 1993 February 5. A GHRS spectrum on 1993 February 21, obtained just 16 days after the spectrum with no detectable C IV absorption, shows strong N V λλ1238.8, 1242.8 absorption lines, also at a radial velocity of -450 km s^-1^. The observations place constraints on the two types of models for absorption-line variability: bulk motion into the line of sight, and variable ionization of gas already in the line of sight. Title: Probing the Chromospheric Structure of Alpha Tau Authors: Carpenter, Kenneth Bibcode: 1996hst..prop.6722C Altcode: 1996hst..prop.3133C Fluorescent H_2 lines {excited by Hydrogen LyAlpha} and Ca II lines formed by recombination after photoionization by H LyAlpha were recently seen in GHRS spectra of the K5 III star Alpha Tau. This is the first time these lines have been seen in a giant star. The presence of these lines provides an opportunity to probe the structure of the upper chromosphere {Ca II} and of the low chromosphere/temperature minimum region {H_2} in this star and to test existing and new theoretical models of the outer atmosphere of Alpha Tau. In addition, the H_2 lines allow us to probe cooler regions than possible using the standard atomic emission line diagnostics and thus enable us to test the hypothesis of Wiedemann et al. {1994 ApJ 423, 806} that the atmosphere of cool giants are thermally bifurcated in the region above the photosphere. We propose to obtain, during Cycle 6, observations of the full set of Ca II and H_2 lines needed to perform these analysis and tests and to use these data to create new models of the chromosphere of Alpha Tau. Title: HST Studies of Carbon and K-M Giant/Supergiant Stars Authors: Carpenter, K. G.; Robinson, R. D. Bibcode: 1996swhs.conf..418C Altcode: No abstract at ADS Title: Empirical constraints on wind flows and turbulence from HST observations of cool giants and supergiants Authors: Carpenter, K. G. Bibcode: 1996ASPC..109..243C Altcode: 1996csss....9..243C No abstract at ADS Title: Rapid UV spectroscopy of flares on YZ CMi Authors: Robinson, R. D.; Woodgate, B. E.; Carpenter, K. G. Bibcode: 1996ASPC..109..285R Altcode: 1996csss....9..285R No abstract at ADS Title: Identification and analysis of UV emission lines observed near 1550 Angstroms in the spectrum of alpha Tau obtained with the GHRS Authors: McMurry, A. D.; Jordan, C.; Rowe, A. K.; Carpenter, K. G.; Robinson, R. D. Bibcode: 1996ASPC..109..271M Altcode: 1996csss....9..271M No abstract at ADS Title: Examining the coronal heating on the RS CVn binary HR 1099 Authors: Airapetian, V.; Robinson, R. D.; Maran, S. P.; Carpenter, K. G. Bibcode: 1996ASPC..109..249A Altcode: 1996csss....9..249A No abstract at ADS Title: The Transition Region, Corona, Chromosphere, and Wind of the K5 Giant gamma Draconis Authors: Brown, A.; Carpenter, K. G.; Robinson, R. D.; Harper, G. M.; Deeney, B. D.; Ayres, T. R. Bibcode: 1995AAS...18710303B Altcode: 1995BAAS...27.1430B Gamma Draconis (K5 III) is the first single, normal late K giant located on the red side of the coronal ``dividing line'' known to show conclusive evidence for both hot ( ~ 10(5) K) transition \ region (TR) and coronal (> 10(6) K) plasma. We present HST GHRS ultraviolet spectra of gamma Dra obtained on 1995 July 20 and 1991 April 6/18. These observations include spectra obtained at low, medium, and echelle resolution that provide a full set of chromospheric and TR emission line fluxes and profiles. These are combined with ROSAT PSPC observations to measure the TR and coronal properties, such as emission measure distribution, electron density, and nonthermal velocity fields, of this star. The high temperature emissions of gamma Dra are compared to those of a sample of hybrid-chromosphere bright giants and supergiants. This work is supported by Space Telescope Science Institute grant GO-06068.01-94A and NASA grants NAG5-1792 and NAGW-4529 to the University of Colorado. Title: The Mass of the Cepheid S Muscae. Authors: Bohm-Vitense, E.; Evans, N. R.; Beck-Winchatz, B.; Carpenter, K.; Robinson, R. Bibcode: 1995AAS...18710205B Altcode: 1995BAAS...27.1428B Using the Goddard High Resolution Spectrograph on the Hubble Space Telescope we have measured the orbital radial velocity changes for the companion of the Cepheid S Muscae. The observations were done at minimum and maximum orbital velocities. The two spectra were cross-correlated. The velocity difference was measured to be 30.6 +/- 0.4 km/s. The difference for the orbital velocities of the Cepheid for the same phases was determined to be 26.9 +/-0.4 km/s. This gives a mass ratio of 1.14 +/-0.06. For a spectral type between B3.5 V and B5 V for the companion S Mus B its mass is 5.0 +/- 0.3 M(sun). With the mass ratio of 1.14 the mass of the Cepheid, with a period of 9.6 days, comes out to be 5.7 +/- 0.4 solar masses. This compares with a pulsational mass of 5.5 solar masses. Taking the 5.7 solar masses for the Cepheid at face value its absolute visual magnitude of M(V)=-4.29 indicates a high degree of excess interior mixing in its main sequence progenitor corresponding to convective overshoot by one pressure scale height. Even for the upper mass limit the excess mixing has to correspond to convective overshoot by 1/2 pressure scale height. Title: The Astrophysical Laboratory RR Tel: Observations Authors: Harper, G. M.; Brown, A.; Robinson, R. D.; Jordan, C.; Carpenter, K. G.; Shore, S. N. Bibcode: 1995AAS...187.1910H Altcode: 1995BAAS...27.1313H The rich emission line spectrum of the bright symbiotic nova RR Tel provides one of the best laboratories for determining empirical values of atomic parameters, including branching ratios, Einstein A-values and electron collision strengths. In addition to providing atomic parameters not measurable in the laboratory, the observations also test recent theoretical calculations of these parameters. In July 1995 we obtained high quality low and medium resolution, large aperture spectra of RR Tel using the Goddard High Resolution Spectrograph (GHRS) on board the Hubble Space Telescope. These spectra sample wavelengths from 1100 Angstroms to 2680 Angstroms and contain numerous lines of astrophysical interest which will be used to derive empirical atomic data (e.g. branching ratios in C II], N III], O III] and O IV]) as well as lines from which the local temperature and density can be determined. The GHRS spectra have greater dynamic range and lower background noise than available high resolution IUE data, permitting detailed evaluation of spectral diagnostics even for the weak emission features from some intercombination and forbidden transitions. In this paper we show examples of the spectra, discuss the atomic transitions for which atomic data will be derived and describe the methods used in determining these parameters. RR Tel and AG Peg, both of which have been observed with the GHRS, are fundamental for studying time variability of spectra of a symbiotic nova and the GHRS observations will be compared with previous IUE results to investigate this variability. We will also discuss the observed flows and turbulence found from the line profiles as well as the shape of the UV continuum. Support for this work was provided by NASA through grant number GO-05863.01-94A from the Space Telescope Science Institute, which is operated by the Association of Universities for research in Astronomy, Inc., under NASA contract NAS5-26555. Title: A Search for Microflaring Activity on dMe Flare Stars. I. Observations of the dM8e Star CN Leonis Authors: Robinson, R. D.; Carpenter, K. G.; Percival, J. W.; Bookbinder, J. A. Bibcode: 1995ApJ...451..795R Altcode: Microflares are frequent, short-duration, energetically weak disturbances occurring in the nonradiatively heated regions of the Sun and other magnetically active stars. They are thought to be the low-energy extension of flares commonly seen on active dMe stars and may be a major source of heating the chromosphere and corona of cool stars in general. In this paper we describe rapid time sequence UV photometry of the dMe star CN Leo taken with the High Speed Photometer (HSP) aboard the Hubble Space Telescope (HST). The filter was centered at 240 nm, near wavelengths at which flares are expected to have maximum intensity and the stellar background is small. During 2 hr of on-source observing, a total of 32 flarelike events were detected, with integrated counts ranging from 12 to more than 14,000. In most cases the events had integrated energy ranging between 1027 and 1028 ergs and can be classified as microflares. A considerable fine structure was seen in these events, with substantial variations sometimes occurring on timescales of less than 1 s. The occurrence rates for the smaller events showed a power-law distribution, with a slope comparable to that seen for larger events observed from the ground. Extrapolating the occurrence rate relation to nanoflare energies indicates a predicted count rate that is significantly smaller than that observed, suggesting that the nanoflares have a different energy distribution than the larger events. Title: The Goddard High Resolution Spectrograph: In-Orbit Performance Authors: Heap, S. R.; Brandt, J. C.; Randall, C. E.; Carpenter, K. G.; Leckrone, D. S.; Maran, S. P.; Smith, A. M.; Beaver, E. A.; Boggess, A.; Ebbets, D. C.; Garner, H. W.; Hutchings, J. B.; Jura, M.; Linsky, J. L.; Savage, B. D.; Cardelli, J. A.; Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Ake, T. B.; Crenshaw, D. M.; Malumuth, E. M.; Robinson, R. D.; Sandoval, J. L.; Shore, S. N.; Wahlgren, G. M.; Bruhweiler, F.; Lindler, D. J.; Gilliland, R. L.; Hulbert, S. J.; Soderblom, D. R. Bibcode: 1995PASP..107..871H Altcode: The in-orbit performance of the Goddard High Resolution Spectrograph onboard the Hubble Space Telescope (HST) is presented. This report covers the pre-COSTAR period, when instrument performance was limited by the effects of spherical aberration of the telescope's primary mirror. The digicon detectors provide a linear response to count rates spanning over six orders of magnitude, ranging from the normal background flux of 0.01 counts diode ^-1 s^-1 to values larger than 10^4 counts diode^-1 s^-1. Scattered light from the first-order gratings is small and can be removed by standard background subtraction techniques. Scattered light in the echelle mode is more complex in origin, but it also can be accurately removed. Data have been obtained over a wavelength range from below 1100 A to 3300 A, at spectral resolutions as high as R = lambda/delta-lambda = 90,000. The wavelength scale is influenced by spectrograph temperature, outgassing of the optical bench, and interaction of the magnetic field within the detector with the earth's magnetic field. Models of these effects lead to a default wavelength scale with an accuracy better than 1 diode, corresponding to 3 km s^-1 in the echelle mode. With care, the wavelength scale can be determined to an accuracy of 0.2 diodes. Calibration of the instrument sensitivity functions is tied into the HST flux calibration through observations of spectrophotometric standard stars. The measurements of vignetting and the echelle blaze function provide relative photometric precision to about 5% or better. The effects of fixed-pattern noise have been investigated, and techniques have been devised for recognizing and removing it from the data. The ultimate signal-to-noise ratio achievable with the spectrograph is essentially limited only by counting statistics, and values approaching 1000:1 have been obtained. (SECTION: Astronomical Instrumentation) Title: Formation of Atomic Emission Lines in the Atmosphere of Jupiter After the Comet Shoemaker-Levy 9 S Impact Authors: Carpenter, K. G.; McGrath, M. A.; Yelle, R. V.; Noll, K. S.; Weaver, H. A. Bibcode: 1995DPS....27.2203C Altcode: 1995BAAS...27Q1118C No abstract at ADS Title: An Atlas of Alpha Orionis Obtained with the Goddard High Resolution Spectrograph on the Hubble Space Telescope Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R.; Snow, M.; Randall, C. E.; Ake, T. B.; Robinson, R. D.; Wahlgren, G. Bibcode: 1995AJ....109.2706B Altcode: An atlas of observations of the late-type supergiant a Orionis taken with the Goddard High Resolution Spectrograph in 1992 September is presented. We have included identifications of the major features along with the fully reduced spectrum. The 33 exposures consist of 3 high resolution (R∼80,000) and 30 medium resolution (R ∼20,000∼35,000) observations. The latter provide complete wavelength coverage from 1980 to 3300 Å. Title: GHRS Observations of Cool, Low-Gravity Stars. II. Flow and Turbulent Velocities in the Outer Atmosphere of gamma Crucis (M3.4 III) Authors: Carpenter, Kenneth G.; Robinson, Richard D.; Judge, Philip G. Bibcode: 1995ApJ...444..424C Altcode: The Goddard High Resoulution Spectrograph (GHRS) on the Hubble Space Telescope (HST) has been used to obtain medium (R = 20,000) and high (R = 85,000) resoultion UV spectra of chromosphere emission features for the M3.4 III star gamma Cru. Small Science Aperture (SSA) G270M and Echelle-B spectra of selected regions in the 2300-2850 A range were obtained to determine the kinematics of the chromosphere using lines of C2), Fe2, Co2, Si1/2), Ni2, Mn2, and Mg2. Profiles of C2) (UV 0.01) lines and fluorescently excited lines of low optical depth indicate average turbulent velocities (Doppler FWHM) of 30.2 +/- 1.3 and 28.8 +/- 1.3 km/s, respectively. The fluorescent emission lines (mean RV = 21.3 +/- 0.9 km/s) and the wings of the emission components of Fe2 lines (mean RV = 22.8 +/- 0.4 km/s) are approximately at rest relative to the radial velocity of the star (21 km/s), while the C2) lines show a modest inflow (mean RV = 23.1 +/- 0.9 km/s). The more opaque lines of Fe2 and Mg2 exhibit complex profiles resulting from line formation in an optically thick, extended expanding atmosphere. The emission wings of these lines are broadened by multiple scattering, and they are centered near the photospheric radial velocity. Closer to line center, these strong lines show a strong blueshifted self-absorption feature (already seen in IUE data), indicative of formation in an expanding chromosphere, and a previously unseen dip in the profiles on the red side of line center. The absorption components, when extracted using simple Gaussian fits, show strong correlations with the relative optical depths of the lines. The derived absorption flow velocities converge to the photospheric velocity as one examines spectra features formed deeper in the atmosphere. The blueward abosrption velocity increases in magnitude from about 7 to 14 km/s with increasing line optical depth - the strong absorptions directly map the acceleration of the outflowing stellar wind, while the interpretation of the weaker redshifted absorptions is more ambiguous, indicating either an inflow of material or formation in an extended, spherically expanding outflow. The Mg2 and Fe2 profiles, taken together, imply that the wind speed decreases between the atmospheric layers where the Mg2 and Fe2 self-absorption components are formed. Interstellar absorptions are seen in the resonance lines of Mg2 (UV 1) and Fe2 (UV1) with zero-volt lower levels, at about -3 km/s, consistent with models of the interstellar medium in the direction of gamma Cru. Finally, we have detected the Mg2 'satellite lines' seen in solar spectra obtained above the limb. In gamma Cru these lines are probably fluorescently excited by H Ly beta. Title: Outer Layers of a Carbon Star: The View from the Hubble Space Telescope Authors: Johnson, Hollis R.; Ensman, Lisa M.; Alexander, David R.; Avrett, Eugene H.; Brown, Alexander; Carpenter, Kenneth G.; Eriksson, Kjell; Gustafsson, Bengt; Jorgensen, Uffe G.; Judge, Philip D.; Linsky, Jeffrey L.; Luttermoser, Donald G.; Querci, Francois; Querci, Monique; Robinson, Richard D.; Wing, Robert F. Bibcode: 1995ApJ...443..281J Altcode: To advance our understanding of the relationship between stellar chromospheres and mass loss, which is a common property of carbon stars and other asymptotic giant branch stars, we have obtained ultraviolet spectra of the nearby N-type carbon star UU Aur using the Hubble Space Telescope (HST). In this paper we describe the HST observations, identify spectral features in both absorption and emission, and attempt to infer the velocity field in the chromosphere, upper troposphere, and circumstellar envelope from spectral line shifts. A mechanism for producing fluoresced emission to explain a previously unobserved emission line is proposed. Some related ground-based observations are also described. Title: MG II H and K Profiles in High-Luminosity, Late-Type Stars Authors: Robinson, R. D.; Carpenter, K. G. Bibcode: 1995ApJ...442..328R Altcode: Using high-resolution spectroscopic data taken with the Goddard High Resolution Spectrographic (GHRS) aboard the Hubble Space Telescope (HST) and with the International Ultraviolet Explorer (IUE) satellite, we compare the profiles of the Mg II h and k lines seen in stars with spectral types ranging from early K through mid-M and luminosities from giants to supergiants. For all of these stars the lines are broad emission features with a central absorption. When plotted on a velocity scale the absorption features of the h and k lines agree very well in both shape and position, as do the blue wings of the emission component. The red wings of the emission, however, show a pronounced difference, with the k line wing consistently shifted to the red of the h line wing. At present the reason for this discrepancy is unknown, but we suggest several possibilities, including radiative transfer effects and high-speed stellar winds. Title: Fe II Line Profiles as Stellar Wind Diagnostics in M Giant and Supergiant Stars Authors: Carpenter, K. G.; Robinson, R. D. Bibcode: 1995AAS...186.2220C Altcode: 1995BAAS...27..844C Detailed study of high resolution, high signal-to-noise chromospheric Fe II emission line profiles, obtained with the Goddard High Resolution Spectrograph on the Hubble Space Telescope, provides an opportunity to probe the flow velocities in the outer atmospheres/winds of cool, low-gravity stars. We have previously reported seeing the acceleration of the outflowing wind in such data from several M-giant stars, including gamma Cru (M3.4 III), mu Gem (M3 IIIab), and alpha Tau (K5 III). Early attempts to do the same with the M-supergiant alpha Ori (M2 Iab) met with limited success, due to the high-opacity of its outer atmosphere and the significant differences in the character and behavior of the observed line profiles in the supergiant spectrum. Further analysis of the GHRS observations of Fe II lines in alpha Ori has now enabled us to detect the accelerating outflow in it's wind as well. A detailed comparison of the observed Fe II profiles and the flows inferred from those profiles, with those for the less-luminous, but similar Teff M-giant gamma Cru are presented. Title: Line Identifications in Goddard High Resolution Spectrograph Observations of Cool, High-Luminosity Stars Authors: Carpenter, K. G.; Robinson, R. D. Bibcode: 1995ASPC...81..559C Altcode: 1995lahr.conf..559C No abstract at ADS Title: Observations of Fe XXI on the RS CVn star HR 1099: deducing the coronal properties Authors: Robinson, R. D.; Airapetian, V. S.; Maran, S. P.; Carpenter, K. G. Bibcode: 1995IAUS..176P.191R Altcode: No abstract at ADS Title: GHRS Spectra of alpha Tau Authors: Carpenter, K.; Robinson, R.; Judge, P. Bibcode: 1994AAS...185.4509C Altcode: 1994BAAS...26.1380C Goddard High Resolution Spectrograph (GHRS) observations of the K5 giant alpha Tau were obtained on 8 April 1994. Spectra of approximately 40 Angstroms-wide regions centered near 1300, 1550, 1660, 1995, 2340, 2760, and 2800 Angstroms were obtained through the Small Science Aperture (SSA) with medium resolution (R=20,000) gratings. These data provide high-precision profiles of a variety of lines formed in the stellar chromosphere and transition region, including O I, Fe II, C I, C II], Si II], Mg II, and C IV. Self-reversed emission from O I, Fe II, and Mg II provide information on the wind flow velocities, with all three ions showing both red and blue-shifted absorption components, as seen previously in the Fe II emission from the later-type giants gamma Cru and mu Gem. The first evidence for hot plasma in the outer atmosphere of alpha Tau is seen in the G160M spectrum centered near 1550 Angstroms@. This spectrum shows very broad, but distinct features due to the C IV (UV 1) doublet, as well as a myriad of much narrower emissions formed at cooler temperatures, such as (fluorescent) Fe II and perhaps Ni II and C I. C I (UV 2) is seen in emission and a comparison of its flux with that in C I (UV 32) will allow an estimation of the C I chromospheric column density. Multiple observations of the C II] (UV 0.01) intercombination multiplet were obtained to search for evidence of shocks and/or propagating waves. Results of that search will be presented. Finally, very high-resolution (R=85,000) echelle spectra were obtained of the Mg II resonance doublet near 2800 Angstroms@. These emission features show strong interstellar, stellar, and circumstellar absorption components at, above, and below the stellar rest velocity. Title: GHRS and IUE Observations of the Symbiotic Binary CI Cygni Authors: Jalakas, M.; Stencel, R. E.; Carpenter, K. G.; Robinson, R. D. Bibcode: 1994AAS...185.2111J Altcode: 1994BAAS...26.1345J The interacting symbiotic binary star, CI Cygni, is a system which consists of a hot star orbiting a red giant. Matter from the larger star is being transfered to the smaller one. Both IUE and more recently, the Goddard High Resolution Spectrograph on HST have detected variable ultraviolet emission lines produced by this transfer. Phase-dependent changes to the doppler velocity of the matter allow us to map the direction of the flow. Using the HST snd IUE spectrometers, we re-examined two different types of lines (resonance and intercombination) which had been reported to show velocity differences. We will present an analysis of these data showing the relative locations of high and low density features in the matter transfer in this system. The lead authors are pleased to acknowledge partial support for this effort through NASA grant NAG5-2368 to the University of Denver. Title: Coronal Heating Mechanisms: A Search for Microflare Activity on YZ CMi Authors: Robinson, R. D.; Carpenter, K. G.; Percival, J. W. Bibcode: 1994AAS...185.4506R Altcode: 1994BAAS...26.1380R We report on time series photometric observations of the dM4.5e flare star YZ CMi taken in 1993 Nov with the High Speed Photometer aboard the Hubble Space Telescope. The data consist of five 30 minute time sequences, with a sampling rate of 0.01s, which were taken through the F240W filter (centered at 240nm with a 800 Angstroms width). This setup was selected since the flare energy is expected to be large and the stellar background is small at these wavelengths. The observations show a stellar background of 120 counts s(-1) on which are superimposed well defined flare events ranging in integrated energy from 10(28) to 10(30) ergs, as well as longer term variations with an amplitude of up to 50% of the continuum intensity and time scales ranging from several minutes to hours. These results are compared with data from the dM8e flare star CN Leo, obtained earlier with the same experimental setup. CN Leo has a quiescent X-ray flux which is 1/30 that of YZ CMi, but had a higher occurrence rate of microflares. On the other hand, the stellar UV background, which must be chromospheric in origin, is less than 1/25th that seen on YZ CMi. This suggests a link between chromospheric and coronal heating. Title: The Goddard High Resolution Spectrograph: Instrument, Goals, and Science Results Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Ake, T. B.; Bruhweiler, F.; Cardelli, J. A.; Lindler, D. J.; Malumuth, E.; Randall, C. E.; Robinson, R.; Shore, S. N.; Wahlgren, G. Bibcode: 1994PASP..106..890B Altcode: The Goddard High Resolution Spectrograph (GHRS), currently in Earth orbit on the Hubble Space Telescope (HST), operates in the wavelength range of 1150-3200A with spectral resolutions (lambda/delta-lambda) of approximately 2 X 10^3, 2 X 10^4, and 1 X 10^5. This paper describes the instrument and its development from inception, its current status, the approach to operations, representative results in the major areas of the scientific goals, and prospects for the future. (SECTION: Instrumentation and Data Analysis) Title: GHRS Observations of Cool, Low-Gravity Stars. I. The Far-Ultraviolet Spectrum of alpha Orionis (M2 Iab) Authors: Carpenter, Kenneth G.; Robinson, Richard D.; Wahlgren, Glenn M.; Linsky, Jeffrey L.; Brown, Alexander Bibcode: 1994ApJ...428..329C Altcode: We present far-UV (1200-1930 A) observations of the prototypical red supergiant star alpha Ori, obtained with the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST). The observations, obtained in both low- (G140L) and medium- (G160/200M) resolution modes, unambiguously confirm that the UV 'continuum' tentatively seen with (IUE) is in fact a true continuum and is not due to a blend of numerous faint emission features or scattering inside the IUE spectrograph. This continuum appears to originate in the chromospheric of the star at temperatures ranging from 3000-5000 K, and we argue that it is not related to previously reported putative companions or to bright spots on the stellar disk. Its stellar origin is further confirmed by overlying atomic and molecular absorptions from the chromosphere and circumstellar shell. The dominant structure in this spectral region is due to nine strong, broad absorption bands of the fourth-positive A-X system of CO, superposed on this continuum in the 1300-1600 A region. Modeling of this CO absorption indicates that it originates in the circumstellar shell in material characterized by T = 500 K, N(CO) = 1.0 x 1018 per sq cm, and Vturb = 5.0 km per sec. The numerous chromospheric emission features are attributed mostly to fluorescent lines of Fe II and Cr II (both pumped by Lyman Alpha) and S I lines, plus a few lines of O I, C I, and Si II. The O I and C I UV 2 multiplets are very deficient in flux, compared to both the flux observed in lines originating from common upper levels but with markedly weaker intrinsic strength (i.e., O I UV 146 and C I UV 32) and to the UV 2 line fluxes seen in other cool, less luminous stars. This deficiency appears to be caused by strong self-absorption of these resonance lines in the circumstellar shell and/or upper chromosphere of alpha Ori. Atomic absorption features, primarily due to C I and Fe II are clearly seen in the G160M spectrum centered near 1655 A. These Fe II features are formed at temperatures that can occur only in the chromosphere of the star and are clearly not photospheric or circumstellar in origin. Title: Examining the Corona of HR 1099 with the Hubble Space Telescope Authors: Robinson, R. D.; Maran, S. P.; Carpenter, K. G.; Brandt, J. C.; Linsky, J. L. Bibcode: 1994AAS...184.0515R Altcode: 1994BAAS...26Q.865R A pilot program for the study of stellar coronae through ultraviolet diagnostic lines is in progress with the Goddard High Resolution Spectrograph on the Hubble Space Telescope. An initial result of this program was the detection of the coronal emission line of Fe XXI at 1354 Angstroms in the quiescent spectrum of the dMe star AU Mic (ApJ 421, 800, 1994). The line appeared to be symmetrical, had no measurable radial velocity with respect to the stellar rest frame, and had a width which was consistent with a thermal gas of temperature 10(7) K, suggesting very small turbulence within the formation region. In March 1994, we observed the RS CVn binary HR 1099 = HD 22468 (K1 IV + G5 IV ) using instrumental settings identical to those employed with AU Mic, but with the added benefit of the recently-installed HST corrective optics (COSTAR). Each exposure was bracketed by observations of an on-board wavelength calibration lamp. The results of the series of eight 27-minute integrations, obtained at one-orbit intervals, will be presented and compared with the AU Mic spectrum. Title: GHRS Observations of the M-Giant MU GEM Authors: Carpenter, K. G.; Robinson, R. D.; Johnson, H. R.; Ensman, L. M. Bibcode: 1994AAS...184.0505C Altcode: 1994BAAS...26..863C The ultraviolet spectrum of the M-giant mu Gem (M3 IIIab) is sampled at selected important wavelengths with the Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST). The wavelength regions are chosen to include lines sensitive to turbulence and flow velocities in the stellar chromosphere and wind acceleration region, as well as some fiducial photospheric absorption features. The dynamics of the outer atmosphere of mu Gem are examined using the observed profiles and positions of chromospheric emission lines of C II, Fe II, Mg II, Fe I, referenced to photospheric absorption lines of Fe I. The content of the spectra and the inferred flow and turbulent velocities are compared to those found for the other cool, low-gravity stars observed with GHRS, including alpha Ori (M2 Iab) and gamma Cru (M3.4 III). Title: Examining the corona of HR 1099 with the Hubble Space Telescope. Authors: Robinson, R. D.; Maran, S. P.; Carpenter, K. G.; Brandt, J. C.; Linsky, J. L. Bibcode: 1994BAAS...26..865R Altcode: No abstract at ADS Title: HST Observations of the Chromosphere of a Carbon Star Authors: Ensman, L. M.; Johnson, H. R.; Carpenter, K. G.; Robinson, R. D.; Luttermoser, D. Bibcode: 1994AAS...184.0506E Altcode: 1994BAAS...26..863E Ultraviolet spectra from the first Hubble Space Telescope observations of a carbon star are presented, as well as line identifications and an initial analysis of the velocity structure of the emitting region. Two spectra of UU Aur (HD 46687, type N3; C5,3) have been obtained. In the lower-resolution FOS spectrum (2310 -- 3275 Angstroms), UV emission lines of Mg I, Mg II, and Fe II, fluoresced lines of Fe I and II, semi-forbidden emission from C II, Si II, and Al II, absorption lines of Fe I and Ti II, and absorption by CH and CaCl have been identified. In the high resolution GHRS spectrum, which covers a 50 Angstroms region around the Mg II h and k emission lines, overlying Mg II and Mn I absorption and two fluoresced Fe I lines have been resolved. The Mg II, and perhaps the Ti II, absorption appears to be interstellar. UV emission lines of predominantly singly ionized metals indicate the existence of a chromosphere at ~ 5000 K. In UU Aur, the Mg II emission clearly arises in material which is flowing away from the star at 35--60 km/s. Shifts of the Fe II emission lines support the conclusion that the chromosphere is expanding at highly supersonic velocities. However, overlying Mn I absorption must be due to stationary material further out. The forbidden and fluoresced lines also come from a region(s) with negligible velocity. These data imply that shocks may form in the atmospheres of carbon stars and thus be a mechanism for chromospheric heating and mass loss. In fact, previous semi-empirical chromospheric models of the carbon star TX Psc (Luttermoser, Johnson, Avrett, and Loeser 1989) indicate a similar shock-like velocity field. Luttermoser, D., Johnson, H. R., Avrett, G., and Loeser, R. 1989, ApJ 345, 543. Title: Ultraviolet and Radio Observations of the Young Rapidly Rotating k0 Dwarf Star HD197890 Authors: Robinson, R. D.; Carpenter, K. G.; Slee, O. B.; Nelson, G. J.; Stewart, R. T. Bibcode: 1994MNRAS.267..918R Altcode: We present the results of UV observations taken with the International Ultraviolet Explorer (IUE) satellite and microwave observations obtained with the Australia Telescope during an observing campaign of the rapidly rotating K0 dwarf star III) 197890, nicknamed `Speedy Mic'. This star was recently recognized as a powerful, transient EUV source by the ROSAT WFC, and subsequent investigation showed it to be a ZAMS or possibly a PMS dwarf which may be a member of the Local Association. Our observations show it to have strong, variable UV emission lines near the `saturation' levels. The radio observations show a level of `quiescent' emission consistent with other rapidly rotating stars, but there is no evidence for the large flux variations that normally characterize the time history of such objects. Title: Observing Stellar Coronae with the Goddard High Resolution Spectrograph. I. The dMe Star AU Microscopii Authors: Maran, S. P.; Robinson, R. D.; Shore, S. N.; Brosius, J. W.; Carpenter, K. G.; Woodgate, B. E.; Linsky, J. L.; Brown, A.; Byrne, P. B.; Kundu, M. R.; White, S.; Brandt, J. C.; Shine, R. A.; Walter, F. M. Bibcode: 1994ApJ...421..800M Altcode: We report on an observation of AU Mic taken with the Goddard High Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope. The data consist of a rapid sequence of spectra covering the wavelength range 1345-1375 A with a spectral resolution of 10,000. The observations were originally intended to search for spectral variations during flares. No flares were detected during the 3.5 hr of monitoring. A method of reducing the noise while combining the individual spectra in the time series is described which resulted in the elimination of half of the noise while rejecting only a small fraction of the stellar signal. The resultant spectrum was of sufficient quality to allow the detection of emission lines with an integrated flux of 10-15 ergs/sq cm(sec) or greater. Lines of C I, O I, O V, Cl I, and Fe XXI were detected. This is the first indisputable detection of the 1354 A Fe XXI line, formed at T approximately = 107 K, on a star other than the Sun. The line was well resolved and displayed no significant bulk motions or profile asymmetry. From the upper limit on the observed line width, we derive an upper limit of 38 km/s for the turbulent velocity in the 107 K plasma. An upper limit is derived for the flux of the 1349 A Fe XII line, formed at T approximately = 1.3 x 106 K. These data are combined with contemporaneous GHRS and International Ultraviolet Explorer (IUE) data to derive the volume emission measure distribution of AU Mic over the temperature range 104-107 K. Models of coronal loops in hydrostatic equilibrium are consistent with the observed volume emission measures of the coronal lines. The fraction of the stellar surface covered by the footprints of the loops depends upon the loop length and is less than 14% for lengths smaller than the stellar radius. From the upper limit to the estimated width of the Fe XXI line profile we find that the we cannot rule out Alfven wave dissipation as a possible contributor to the required quiescent loop heating rate. Title: Search for CO Absorption Bands in IUE Far-Ultraviolet Spectra of Cool Stars Authors: Gessner, S. E.; Carpenter, K. G.; Robinson, R. D. Bibcode: 1994AJ....107..747G Altcode: Observations of the red supergiant (M2 Iab) alpha Ori with the Goddard High Resolution Spectrograph (GHRS) on board the Hubble Space Telescope (HST) have provided an unambiguous detection of a far-ultraviolet (far-UV) chromospheric continuum on which are superposed strong molecular absorption bands. The absorption bands have been identified by Carpenter et al. (1994) with the fourth-positive A-X system of CO and are likely formed in the circumstellar shell. Comparison of these GHRS data with archival International Ultraviolet Explorer (IUE) spectra of alpha Ori indicates that both the continuum and the CO absorption features can be seen with IUE, especially if multiple IUE spectra, reduced with the post-1981 IUESIPS extraction procedure (i.e., with an oversampling slit), are carefully coadded to increase the signal to noise over that obtainable with a single spectrum. We therefore initiated a program, utilizing both new and archival IUE Short Wavelength Prime (SWP) spectra, to survey 15 cool, low-gravity stars, including alpha Ori, for the presence of these two new chromospheric and circumstellar shell diagnostics. We establish positive detections of far-UV stellar continua, well above estimated IUE in-order scattered light levels, in spectra of all of the program stars. However, well-defined CO absorption features are seen only in the alpha Ori spectra, even though spectra of most of the program stars have sufficient signal to noise to allow the dectection of features of comparable magnitude to the absorptions seen in alpha Ori. Clearly if CO is present in the circumstellar environments of any of these stars, it is at much lower column densities. Title: A Search For Microflaring Activity on dMe Flare Stars Authors: Robinson, R. D.; Carpenter, K. G.; Percival, J. W. Bibcode: 1994ASPC...64..456R Altcode: 1994csss....8..456R No abstract at ADS Title: GHRS Observations and Analysis of the 0 I and C I Resonance Lines in the UV Spectrum of alpha ORI (M2 Iab) Authors: Carpenter, Kenneth G.; Robinson, Richard D.; Judge, Philip G.; Ebbets, Dennis C.; Brandt, John C. Bibcode: 1994ASPC...64...56C Altcode: 1994csss....8...56C No abstract at ADS Title: Coordinated Space and Ground-Based Observations of the Flare Star YZ CMi Authors: Carpenter, Kenneth G. Bibcode: 1994iue..prop.4768C Altcode: We propose IUE ultraviolet observations of the flare star YZ CMi to complement high time resolution data to be acquired with the Goddard High Resolution Spectrograph on Hubble Space Telescope and other ground and space-based observatories including the AAT, ROSAT, and EUVE. The HST observations are designed to search for the signature of downflowing proton beams during flare events and to estimate their importance in providing the energy that powers the flare. These IUE observations, which include the full range of transition region and chromospheric lines, are critical to determining the energy balance and atmospheric structure of any flare observed. The extended dataset, including non-flare spectra, will allow us to characterize the overall activity level of the star at the time of the observations, and thus place the events in the proper context. Title: The Chromosphere of Alpha Tau - Cycle 4 Medium Authors: Carpenter, Kenneth Bibcode: 1994hst..prop.5358C Altcode: 1994hst..prop.1804C We propose observations of the K5 III star Alpha Tau using the Goddard High-Resolution Spectrograph (GHRS), to follow-up on the exciting initial SAO observations of this star and the SV observations of the K5 III hybrid star Gamma Dra. These data will also allow a detailed comparison of its spectrum and the thermodynamic properties of its outer atmosphere with those of the cooler M giant and supergiant stars Gamma Cru and Alpha Ori, observed during previous cycles. We shall check for variations in the C II downflow discovered in the SAO observations and search for evidence of systematic flows in other emission lines. We shall make detailed comparisons of the chromospheric emission lines and wind signatures in the UV spectra of two stars of the same spectral class, where one is a hybrid and one is not. We shall search for evidence of shocks and/or propagating waves in the line variations predicted by our recent calculations. We will also determine the variation of wind velocity with height using semi-empirical non-LTE models assuming spherical symmetry, search for evidence of circumstellar and interstellar absorptions on resonance lines of O I, Fe II, and Mg II, and compare the short-wavelength continuum measured in this star with that detected in observations of Gamma Dra, Gamma Cru and Alpha Ori. Title: Spectra and Chromospheres of Carbon and M Stars - CYCLE4 Medium Authors: Carpenter, Kenneth Bibcode: 1994hst..prop.5359C Altcode: 1994hst..prop.1805C We propose to use the Faint Object Spectrograph (FOS) and the Goddard High-Resolution Spectrograph (GHRS) on the HST to obtain ultraviolet spectra of visually bright N-type carbon stars and late M-giant stars. These spectra, obtainable only with HST, will be used with theoretical models to infer the temperature and density structure and the velocity fields of the outer atmosphere in these evolutionarily advanced, non-mira giants. In anticipation of this effort, we have already pushed IUE to its limit to obtain both low-resolution, and, where possible, high-resolution spectra of several M, S, and C stars, and these have been analyzed and published. Based upon the observed line profiles and continua, we will construct semi-empirical non-LTE models in both plane-parallel geometry and spherical geometry, including velocity fields, by attaching a chromosphere to theoretical photospheric models. Two-component models will be studied. Using these and ab-initio hydrodynamic models, we will examine the mechanisms responsible for chromospheric heating and mass loss. A full range of supporting ground-based observations will be undertaken to permit us to connect models of the photospheres, chromospheres, and circumstellar shells. Title: On the Weakness of C I and O I Resonance Line Emission from the Chromosphere of alpha Ori. Authors: Carpenter, K.; Robinson, R.; Judge, P.; Ebbets, D.; Brandt, J. Bibcode: 1993AAS...183.1504C Altcode: 1993BAAS...25Q1313C The resonance lines from multiplets UV 2 of both O I and C I are typically quite strong in emission in the far-UV spectrum of cool stars. However, in the prototypical M-supergiant alpha Ori, these lines are remarkably weak, although other transitions from the same upper energy levels, O I (UV 146) and C I (UV 32), are observed in strong emission despite their much weaker intrinsic strengths. Due to the presence of many lines from other species in the regions around the UV 2 multiplets of O I and C I near 1302 Angstroms and 1655 Angstroms, the lines of interest suffer severe blending and progress in understanding this flux deficiency is difficult based on low resolution IUE and GHRS data. We have therefore obtained medium resolution (R=10,000) GHRS spectra of alpha Ori of these complex spectral regions, as well as the regions around the O I (UV 146) and C I (UV 32) lines near 1640 Angstroms and 1993 Angstroms, respectively, to resolve the various contributors and allow detailed study of this phenomenon. In this paper, we present the spectra and discuss the formation of the O I, C I, Fe II, and S I lines which they clearly resolve. Semi-empirical modeling of the outer atmosphere of alpha Ori and detailed radiative transfer calculations are used to study the creation and destruction of O I and C I photons. Title: A Search for Proton Beams during Flares on AU Microscopii Authors: Robinson, R. D.; Carpenter, K. G.; Woodgate, B. E.; Maran, S. P. Bibcode: 1993ApJ...414..872R Altcode: We report the results of a coordinated observing campaign on the active M dwarf star AU Mic. The purpose of the campaign was to search for evidence of proton beams during the impulsive phase of stellar flares and to determine whether the energy contained in these beams represented a significant fraction of the energy budget of the flare. During a total of 3.5 hr of monitoring a small flare was observed simultaneously by the HST, IUE, and the AAT. This event, which had a total optical + UV emission of 1.3 x 10 exp 32 ergs, occurred during the decay phase of a much larger event and showed no evidence for a proton beam with an energy greater than a few times 10 exp 29 ergs/s. This is comparable to the maximum energy flux released by the flare, though this energy release rate must occur over a time interval much shorter than that of the impulsive phase itself. We conclude that the proton beams may be capable of transporting some energy during the impulsive phase of a flare, but that they are unlikely to be the major contributor, at least for this particular event. Title: GHRS Observations of the M-giant gamma CRU Authors: Carpenter, K.; Robinson, R.; Gessner, S. Bibcode: 1993AAS...182.4613C Altcode: 1993BAAS...25..875C The Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope has been used to obtain medium (R=20,000) and high (R=85,000) resolution UV spectra of chromospheric emission features for the M3.4 III star gamma Cru. Large Science Aperture (LSA), medium resolution spectra were obtained to survey the 1980 - 2200 Angstroms region with good signal-to-noise. Small Science Aperture (SSA) G270M and Echelle-B spectra of selected longer wavelength regions were obtained to allow the measurement of velocity flows and turbulence for a variety of ions, including C II, Fe II, Co II, Si I/II, Ni II, Mn II, and Mg II. Gaussian fits to the optically thin C II (UV 0.01) intercombination lines and fluorescently-excited lines of Co II, Ni II, Fe II, and Si I indicate average turbulent velocities (Doppler FWHM) of 30.2 and 28.6 km/s, respectively. For comparison, the C II turbulent velocity previously measured for the K5 giant alpha Tau is ~ 24 km/s. The measured radial velocities of the fluorescent lines average 21.5 km/s, which places them basically at rest relative to the radial velocity of the star (21 km/s), while the C II lines average 23.1 km/s, a modest inflow of a couple of km/s. A subset of the collisionally-excited Fe II emission lines show an average radial velocity of 22.6 km/s, also a very modest inflow, at best. The stronger Fe II lines exhibit a more complex profile which consists of a broad emission line with an ~ 40 km/s FWHM, on which are superposed two absorption components. The stronger component appears at relatively low radial velocity (in the 7 - 15 km/s range) in each line, with a mean value over the sample of ~ 10.5 km/s, while the weaker component appears at relatively high radial velocity in each line (in the range from 25 to 34 km/s), with a mean value of ~ 31.3 km/s. The first represents an outflow of about 10 km/s, while the second an inflow of about 10 km/s. The Mg II h and k emission lines also show the dual-absorption structure seen in the Fe II lines. However, both the emission and absorption components in the k-line are red-shifted by 7 to 9.5 km/s, relative to their equivalent components in the h-line. Title: MG II H and K Profiles in Luminous, Cool Stars Authors: Robinson, R. D.; Carpenter, K. G. Bibcode: 1993AAS...182.4619R Altcode: 1993BAAS...25..877R As part of an investigation of the velocity fields in the atmospheres of cool, luminous stars we used the Goddard High Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope to obtain a high resolution spectrum of the Mg II h and k lines in the M supergiant alpha Ori. These strong, centrally reversed emission lines have been well studied by the IUE. While the h line in alpha Ori has nearly equal intensity in the red and blue peaks, the blue peak of the k line is always much weaker than the red peak. This asymmetry is normally explained as resulting from absorption by Fe I and Mn I in the circumstellar shell. An examination of the GHRS spectrum, however, reveals that the asymmetry results from a velocity shift between the emission wings and the central absorption core of the line. Further, while the central absorption profiles for the h and k lines agree very well when plotted on a velocity scale, the centroid of the k line emission wings was observed to be redshifted by approximately 23 km/s with respect to that of the h line. Examination of other high resolution GHRS observations of Mg II showed a similar, though less pronounced, relative redshift of the k line centroid on the normal M giant gamma Cru and the hybrid K giant gamma Dra. To date, no concrete model has been proposed to explain these shifts. Examining well exposed, high resolution IUE observations of alpha Ori shows a close agreement with the GHRS results. This gives us confidence that we can use IUE spectra to study the relative shapes and velocities of the Mg II h and k lines and we are currently involved in a program to use the IUE archive to quantify the behavior of the Mg II h and k profiles as a function of luminosity and spectral type for luminous, cool stars. The results of this program will be presented. Title: A Search for CO Absorption Bands in IUE Spectra of Cool Stars Authors: Gessner, S.; Carpenter, K.; Robinson, R. Bibcode: 1993AAS...182.4612G Altcode: 1993BAAS...25..875G Observations of the red supergiant (M2 Iab) alpha Ori with the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope (HST) have provided an unambiguous detection of a far-UV continuum on which are superposed strong molecular absorption bands (Carpenter 1991, ASP Conf. Ser. 26, p. 17). The continuum is formed in the stellar chromosphere. The absorption bands, which appear in the 1300 - 1600 Angstroms spectral region, have been identified with the (n,0) bands (n=0,...,8) of the 4th-positive A-X system of CO and are likely formed in the circumstellar shell. Comparison of these GHRS data with archival IUE spectra indicates that both the continuum and the CO absorption features can be seen with IUE, especially if multiple IUE spectra, reduced with the post-1981 IUESIPS extraction procedure (i.e., with an oversampling slit), are carefully co-added to increase the signal-to-noise over that obtainable with a single spectrum. We have therefore begun a program, utilizing both new and archival IUE spectra, to survey other cool, low-gravity stars for the presence of these two new chromospheric and circumstellar shell diagnostics. We hope to identify promising targets for examination with HST spectrographs at the higher resolution and signal-to-noise needed for quantitative analysis. The initial results of this IUE survey are presented here. Title: Observations of 3C 273 With the Goddard High Resolution Spectrograph on the Hubble Space Telescope Authors: Brandt, J. C.; Heap, S. R.; Beaver, E. A.; Boggess, E. A.; Carpenter, K. G.; Ebbets, D. C.; Hutchings, J. B.; Jura, M.; Leckrone, D. S.; Linsky, J. L.; Maran, S. P.; Savage, B. D.; Smith, A. M.; Trafton, L. M.; Walter, F. M.; Weymann, R. J.; Snow, M.; Randall, C. E.; Lindler, D. J.; Shore, S. N.; Morris, S. L.; Gilliland, R. L.; Lu, L.; Robinson, R. D. Bibcode: 1993AJ....105..831B Altcode: The observations of the quasar 3C 273 taken with the Goddard High Resolution Spectrograph in 1991 February are presented here. We have included both the reduced raw data, and smoothed and deconvolved spectra. Also, a list of observed absorption lines is presented. The data comprise 11 spectra, including 1 low resolution observation and 10 medium resolution observations. The wavelength region covered ranged from about 1150 to 2820 A, but was not all inclusive. The procedures used to obtain and reduce the data, including corrections for fixed pattern noise, compensation for the effects of spherical aberration in the HST primary mirror, and objective detection of weak absorption lines, are described. We also have included a short discussion on the detection of galactic Ni II and Virgo cluster metal lines. Title: Atomic data needs for the analysis of the ultraviolet spectrum of cool stars. Authors: Carpenter, K. G. Bibcode: 1993PhST...47..139C Altcode: A brief introduction to the UV spectra of cool stars is given, followed by a review of astronomical observatories and instruments which are capable of acquiring UV spectral data on cool stars. Examples of observational data are presented, along with a description of typical analysis performed on such data. The basic atomic data needed to perform these analysis are summarized, with the most important UV multiples or transitions of the most relevant ions identified. Title: CO Molecular Absorption in Far-UV Spectra of Cool Stars Authors: Carpenter, Kenneth G. Bibcode: 1993iue..prop.4498C Altcode: We propose a far-UV survey of cool giant and supergiant stars to search for evidence of circumstellar absorption by the CO molecule. This survey is motivated by the discovery of a far-UV continuum and superposed circumstellar CO absorption in a spectrum of alpha Ori (M2 Iab) obtained with HST and the subsequent demonstration that IUE is capable of detecting these bands. These bands are an excellent probe of the circumstellar regions of such stars, and provide diagnostics of layers not well sampled by other techniques. Where possible, very rough estimates of the conditions in the regions represented by the CO absorption will be obtained on the basis of these IUE data. The results of this survey will then be used to select targets /individual bands for observation at higher resolution with the GHRS/HST to allow detailed comparison with models and more precise determinations of temperatures and column densities in the circumstellar environment of these stars. Title: Observations of a Flare on AU MIC Authors: Robinson, R. D.; Carpenter, K. G.; Woodgate, B. E. Bibcode: 1992AAS...181.5104R Altcode: 1992BAAS...24.1206R We report the results of a coordinated observing campaign of the active dMe flare star AU Mic, carried out on 1992 Sept 9. Participating instruments include the HST and IUE satellites and the 3.9m Anglo-Australian Telescope. During this campaign a long duration, 1.5 mag (U band) flare was detected, with the maximum phase observed simultaneously with the IUE and AAT and the decay phase monitored by all three instruments. The AAT observations consisted of a time series of CCD exposures covering the wavelength range 3650-4450 Angstroms and having a temporal resolution of 6 seconds. The impulsive phase lasted for about 1 minute and was therefore well resolved by these observations. The flare showed pronounced broadening of the Balmer series, with the Balmer line fluxes increasing with the continuum during the impulsive phase but having a much longer decay time. A pronounced HeII (4026 Angstroms ) emission was seen during the flare, with some indication that this line increased in absorption strength about 30 seconds before the continuum increase. The CaII H and K lines decreased in strength during the impulsive and early decay phase of the event, but recovered during the later decay phase. A low resolution LWP exposure was taken by the IUE during the peak of the flare. Combining this with the optical data gives an almost complete coverage of the flare spectrum from 2200 to 4500 Angstroms . We discuss the implications of these observations in relation to current flare models. Title: The Search for Acoustically-Driven Mass-Loss in Evolved Stars Authors: Stencel, R. E.; Brown, A.; Carpenter, K. G.; Cuntz, M.; Judge, P. Bibcode: 1992AAS...181.3603S Altcode: 1992BAAS...24.1175S Recent ab-initio calculations of stochastic stellar wind models by Cuntz (1992 in Cool Stars VII, ASP Conf. Ser. 26, p.383) have proven remarkably robust in predicting observed chromospheric flow patterns including possible variabilities with time in selected cool, evolved stars. The calculations solve the equations of hydrodynamics using the method of characteristics and assume: (i) saw-tooth shock wave profiles, and (ii) wave periods were changed stochastically while keeping the wave amplitudes constant (see Cuntz 1990 Ap.J. 349, p.141). Among the results of fitting chromospheric flow velocities is the implication that the permitted range of acoustic wave periods for a given star is constrained. We made use of the IUE satellite during August and September 1992 to repeatedly observe two stars, the yellow giant Aldebaran (K5 III) and the red supergiant, Betelgeuse (M2 Iab), in order to sample variations in their atmospheres on timescales of ~ 10(4) to ~ 10(6) seconds, which bracket the predicted mean acoustic wave periods for these objects. In particular, we obtained deep exposures in order to measure density-sensitive line ratios within the C II] intercombination features near 2325A (cf. Lennon et al. 1985 Ap.J. 294, p.200) to test the hypothesis that density fluctuations could be measured as a consequence of these acoustic waves. The results of these observations will be presented and discussed in terms of the number and amplitude of acoustic waves contributing to chromospheric heating and mass loss from these stars, as well as the wave origins in the evolving oscillatory structure of these stellar interiors. We are pleased to acknowledge IUE--NASA grant NAG5-2103 for partial support of this effort. Title: Detection of a Proton Beam during the Impulsive Phase of a Stellar Flare Authors: Woodgate, Bruce E.; Robinson, Richard D.; Carpenter, Kenneth G.; Maran, Stephen P.; Shore, Steven N. Bibcode: 1992ApJ...397L..95W Altcode: A transient event consistent with the predicted temporal and spectral signatures of an energetic proton beam was detected in the impulsive phase of a small flare on the red dwarf star AU Microscopii. It consisted of a prominent increase in the flux in the red wing of Lyman-alpha near 1223 A, simultaneously with the peak of a flare observed in the 1206 A transition region line of Si III. The probability that the red wing event was a chance fluctuation is one chance in 2.5 x 10 exp 4. This observation represents a confirmation of the prediction by Orrall and Zirker (1976) in which downstreaming protons accelerated during the impulsive phase of a flare charge exchange with ambient neutral hydrogen and emit Lyman-alpha radiation from 1 to 15 A redward of line center. Title: The Ultraviolet Photospheric Spectrum of Alpha Orionis Authors: Wahlgren, G. M.; Robinson, R. D.; Carpenter, K. G. Bibcode: 1992AAS...18110010W Altcode: 1992BAAS...24.1280W No abstract at ADS Title: Plasma Flows in the Outer Atmosphere of α Ori Authors: Carpenter, K.; Robinson, R.; Wahlgren, G.; Brandt, J.; Linsky, J.; Ebbets, D.; Weymann, R. Bibcode: 1992AAS...181.5111C Altcode: 1992BAAS...24.1207C No abstract at ADS Title: Detection of a Proton Beam during the Impulsive phase of a Stellar Flare Authors: Woodgate, B. E.; Robinson, R. D.; Carpenter, K. G.; Maran, S. P.; Shore, S. Bibcode: 1992AAS...180.3010W Altcode: 1992BAAS...24..777W We present evidence for the detection of a proton beam during the impulsive phase of a flare on the Dme star AU Microscopii. At 1991 Sept 3 04h 56m 10s UT, the Goddard High Resolution Spectrograph on the Hubble Space Telescope observed an increase in the flux in the red wing of the hydrogen Lyman alpha line at 1223A, unaccompanied by an increase in the blue wing, simultaneously with an increase in the flux of the SiIII 1206A transition region line. The 1223A flux increase was 2.2 x 1027 ergs s-1 A-1, with 3s duration. The chance probability of the observation is 1 in 105. This effect was predicted by Orrall and Zirker (1976), as a downstreaming beam of protons charge exchanging with ambient neutral hydrogen and emitting Lyman alpha radiation at the downstreaming velocity. The energy in the beam is estimated as 7 x 1029 ergs s-1. Title: A Search for Short-Timescale Variations in the Chromosphere; UV Spectrum of the M-Giant Gamma Crucis Authors: Cheng, K. -P.; Carpenter, K. G. Bibcode: 1992ASPC...26...43C Altcode: 1992csss....7...43C No abstract at ADS Title: The Chromosphere and Circumstellar Shell of α Orionis as Observed with the Goddard High Resolution Spectrograph Authors: Carpenter, K. G.; Robinson, R. D.; Wahlgren, G. M.; Linsky, J. L.; Brown, A. Bibcode: 1992ESOC...44..387C Altcode: 1992swhs.conf..387C No abstract at ADS Title: Detection of a Proton Beam during the Impulsive Phase of a Stellar Flare Authors: Robinson, R. D.; Woodgate, B. E.; Carpenter, K. G.; Maran, S. P.; Shore, S. N. Bibcode: 1992ESOC...44..447R Altcode: 1992swhs.conf..447R No abstract at ADS Title: Late-Type Stars (Invited Review) Authors: Carpenter, K. G. Bibcode: 1992ASPC...26...17C Altcode: 1992csss....7...17C No abstract at ADS Title: A Search for CO Molecular Absorption in Far-UV Spectra of Cool Stars Authors: Carpenter, Kenneth G. Bibcode: 1992iue..prop.4214C Altcode: We propose a far-UV survey of cool giant and supergiant stars to search for evidence of circumstellar absorption by the CO molecule. This survey is motivated by the discovery of a far-UV continuum and superposed circumstellar CO absorption in a spectrum of alpha Ori (M2 lab) obtained with HST and the subsequent demonstration that IUE is capable of detecting these bands. These bands are an excellent probe of the circumstellar regions of such stars, and provide diagnostics of layers not well sampled by other techniques. Where possible, very rough estimates of the conditions in the regions represented by the CO absorption will be obtained on the basis of these IUE data. The results of this survey will then be used to select targets/individual bands for observation at higher resolution with the GHRS/HST to allow detailed comparison with models and more precise determinations of temperatures and column densities in the circumstellar environment of these stars. Title: HST Observations of the Flare Star AU MIC Authors: Robinson, R. D.; Shore, S. N.; Carpenter, K. G.; Woodgate, B. E.; Maran, S. P.; Brandt, J. C.; Kundu, M. R.; White, S. M.; Linsky, J. L.; Walter, F. M. Bibcode: 1992ASPC...26...31R Altcode: 1992csss....7...31R No abstract at ADS Title: Molecular Absorption in the UV Spectrum of A ORI Authors: Wahlgren, G. M.; Robinson, R. D.; Carpenter, K. G. Bibcode: 1992ASPC...26...37W Altcode: 1992csss....7...37W No abstract at ADS Title: Chromospheres and winds of cool stars Authors: Carpenter, K. G. Bibcode: 1992HiA.....9..477C Altcode: No abstract at ADS Title: Simultaneous IUE/HST-GHRS Observations of AU MIC Authors: Carpenter, Kenneth G. Bibcode: 1992iue..prop.4212C Altcode: We propose to monitor the early dwarf-M flare star and BY Dra variable AU Mic over two IUE shifts approximately centered on the time of HST observations with the GHRS. The GHRS observations are part of a Cycle 1 HST GO program that is to be reexecuted in late summer of 1992, due to an intermittent HST instrument failure during the initial execution of the HST program in September 1991. The GHRS observations cover a single, very narrow range of wavelengths (36 A) containing Lyman-alpha, Si III 1206 A, and O V 1218 A. They will be obtained at very high time resolution (0.4 sec/integration) and are designed to look for evidence of proton downflow during the impulsive phase of a flare. We request simultaneous IUE observations to place the HST observations in a broader context, which will include a wider variety of chromospheric and transition region lines and their behavior over a 16 hour period approximately centered on the time of the GHRS observations. IUE data is critically needed during flare detections by HST, so that the radiative losses in the UV can be estimated and compared to the energy carried in the proton downflow, in order to evaluate the importance of this energy source to the flare. Title: Zeta-Aurigae Type Binaries Authors: Carpenter, K. G. Bibcode: 1992IAUS..151...51C Altcode: No abstract at ADS Title: SI II emission line diagnostics. Authors: Judge, P. G.; Carpenter, K. G.; Harper, G. M. Bibcode: 1991MNRAS.253..123J Altcode: The present study compares ratios of Si II UV emission lines in a variety of objects with computations based on recently published collisional data of Dufton and Kingston (1991). A high-quality spectrum of Alpha Tau (K5 III) obtained by Carpenter et al. (1991) is analyzed using the G270M mode of the GHRS on the HST, in addition to high-dispersion data from Skylab and IUE. Agreement between observation and theory is satisfactory for most lines. A blend with a line of Ni II accounts partially for the discrepancies and solves a problem with semiforbidden S II emission measures. Disagreement exists between certain observed flux ratios and computed values using recent atomic data for the intersystem lines. The discrepancy is most significant for Alpha Tau. The computed atomic collision strengths within the intersystem multiplet itself are argued as a possible cause of the discrepancy. Title: An Investigation of the Flare Star AU Mic with the Goddard High Resolution Spectrograph on the Hubble Space Telescope Authors: Maran, S. P.; Woodgate, B. E.; Carpenter, K. G.; Robinson, R. D.; Shore, S. N.; Linsky, J. L.; Brown, A.; Byrne, P. B.; Kundu, M. R.; White, S.; Brandt, J. C.; Shine, R. A.; Walter, F. M. Bibcode: 1991BAAS...23.1382M Altcode: No abstract at ADS Title: Coordinated IUE/HST Observations of the Flare Star AU mic: Results from IUE Authors: Carpenter, K. G.; Maran, S. P.; Brown, A.; Linsky, J. L.; Robinson, R. D.; Byrne, P. B.; Judge, P. G. Bibcode: 1991BAAS...23.1383C Altcode: No abstract at ADS Title: Molecular Absorption in the Ultraviolet Spectrum of Alpha Ori Authors: Wahlgren, G. M.; Robinson, R. D.; Carpenter, K. G. Bibcode: 1991BAAS...23.1386W Altcode: No abstract at ADS Title: Time Resolved Observations of the Lyman-Alpha Region in AU Mic with the Goddard High Resolution Spectrograph Authors: Woodgate, B. E.; Maran, S. P.; Carpenter, K. G.; Robinson, R. D.; Shore, S. N.; Linsky, J. L.; Byrne, P. B.; Kundu, M. R. Bibcode: 1991BAAS...23.1383W Altcode: No abstract at ADS Title: First Results from the Goddard High-Resolution Spectrograph: The Chromosphere of alpha Tauri Authors: Carpenter, Kenneth G.; Robinson, Richard D.; Wahlgren, Glenn M.; Ake, Thomas B.; Ebbets, Dennis C.; Linsky, Jeffrey L.; Brown, Alexander; Walter, Frederick M. Bibcode: 1991ApJ...377L..45C Altcode: The K5 III star Alpha Tau was observed with the Goddard High Resolution Spectrograph on November 27, 1990 as part of the Science Assessment Program for the HST. The spectra show intersystem and permitted chromospheric emission lines of semiforbidden C II and Si II, Fe II, Fe I, Ni II, and Co II. Resolved profiles of the semiforbidden C II lines indicate a complex chromospheric turbulent velocity distribution with mean value of roughly 24 km/s, while their observed wavelengths indicate a 4 km/s downflow of the semiforbidden C II plasma. Twenty-five new emission lines have been found in the 2320-2370 A region, 17 of which have been identified with the aid of Skylab data obtained above the solar limb, including four lines from Co II (UV 8) and an Fe I (UV 12) line. Title: Physical Conditions and Velocity Structures in the Red Giant Winds in the Binaries CI CYG and EG and -- Cycle 2 Authors: Carpenter, Kenneth Bibcode: 1991hst..prop.3934C Altcode: This proposal represents a two pronged attack aimed at understanding the detailed chracteristics of red giant winds in binary star systems. Red giant winds can provide the most massive, sustained form of mass transfer in binaries. The symbiotic and related stars, which contain red giant and hot companion stars, permit line of sight studies through a range of red giant atmospheric heights. The goal of this work is to attempt to define both the mechanism of rapid mass loss in red giant stars and the details of mass transfer to the companion stars. Such results can provide important constraints for both stellar and binary evolution theories. In each case we expect to derive density and temperature values for the red giant wind region and compare this to the present understanding of single star conditions where low temperature, dust and molecule forming, circumstellar envelopes prevail. Title: Revised Faint Target/bright Neighbor Test Authors: Carpenter, Kenneth Bibcode: 1991hst..prop.3416C Altcode: Verify capability of HRS to detect weak emission despite immediate proximity of a bright source. Measure near-angle scattering into HRS apertures from adjacent bright source. Revised July 24, 1991 by DCE to complete sequences lost during April 91 execution when carrousel safed. Revised March 1992 BY DCE for SSA G160M 1300 only Title: GHRS Spectroscopy of Cool Stars. II. Authors: Brown, A.; Linsky, J.; Carpenter, K.; Robinson, R.; Ebbets, D. Bibcode: 1991BAAS...23R.910B Altcode: 1991BAAS...23..910B No abstract at ADS Title: GHRS Far-Ultraviolet Spectra of the Coronal Giant Capella Binary Authors: Linsky, J. L.; Brown, A.; Carpenter, K.; Robinson, R. Bibcode: 1991BAAS...23..910L Altcode: No abstract at ADS Title: GHRS Spectroscopy of Cool Stars. I. Authors: Carpenter, K.; Robinson, R.; Ebbets, D.; Brown, A.; Linsky, J. Bibcode: 1991BAAS...23..910C Altcode: No abstract at ADS Title: GHRS / Goddard High Resolution Spectrograph / Far Ultraviolet Spectra of Coronal and Noncoronal Stars - Capella and Gamma-Draconis Authors: Linsky, J. L.; Brown, A.; Carpenter, K. G. Bibcode: 1991fyho.conf...70L Altcode: No abstract at ADS Title: Ghrs/ Goddard High Resolution Spectroscopy Chromospheric Emission Line Spectra of the Red Giant Alpha-Tauri Authors: Carpenter, K. G.; Robinson, R. D.; Ebbets, D. C.; Brown, A.; Linsky, J. L. Bibcode: 1991fyho.conf..212C Altcode: No abstract at ADS Title: Simultaneous IUE/HST-GHRS Observations of AU MIC Authors: Carpenter, Kenneth G. Bibcode: 1991iue..prop.3944C Altcode: We propose to monitor the early dwarf-M flare star and BY Dra variable AU Mic over a two day period centered on the time of HST observations with the GHRS. The GHRS observations are part of the GHRS Investigation Definition Teams's Guaranteed Time Observing (GTO) program and are already approved. The GHRS observations cover a single, very narrow range of wavelengths (1342 - 1378 A) and their prime purpose is to detect and measure lines formed in the corona and in coronal flares, such as Fe XXI 1354 A and Fe XII 1349 A, that are too weak to be observed by IUE, along with a single transition region line (0 V) and lines from one chromospheric ion (C 1). We request simultaneous IUE observations to place the HST observations in a broader context, which will include a wider variety of chromospheric and transition region lines and their behavior over a 48 hour period approximately centered on the time of the GHRS observations. The GHRS observations are to be scheduled during HST Cycle 0, which (based on a December 1989 launch) covers the period February 15 - July 15, 1990 and could occur during either the 12th or 13th IUE observing episodes. This proposal is thus for two years, but all the NASA and ESA shifts are required to be contiguous and at a time which will overlap the HST observations. Title: Alpha Orionis GHRS Team Project -- Cycle 1 Authors: Carpenter, Kenneth Bibcode: 1990hst..prop.1199C Altcode: The HRS will be used to obtain high signal/noise spectra of the 1980 - 3300 A spectral region of the M2 Iab supergiant Alpha Orionis. This full wavelength region will be observed at medium resolution, while 3 selected wavelength regions will be observed in the echelle mode. Exposure times have been chosen so that both the chromospheric emission line spectrum and the photospheric continuum and absorption line spectrum will be properly exposed. These observations will be combined and published in atlas format. It is hoped that this atlas will provide a standard against which high-resolution UV observations of other late-type stars can be compared. Detailed analysis of these data are planned by various IDT members. Title: Physical Conditions and Velocity Structures in the Red Giant Winds in the Binaries CI CYG and EG and -- Repeat for HOPR#67 Authors: Carpenter, Kenneth Bibcode: 1990hst..prop.4251C Altcode: This proposal represents a two pronged attack aimed at understanding the detailed chracteristics of red giant winds in binary star systems. Red giant winds can provide the most massive, sustained form of mass transfer in binaries. The symbiotic and related stars, which contain red giant and hot companion stars, permit line of sight studies through a range of red giant atmospheric heights. The goal of this work is to attempt to define both the mechanism of rapid mass loss in red giant stars and the details of mass transfer to the companion stars. Such results can provide important constraints for both stellar and binary evolution theories. In each case we expect to derive density and temperature values for the red giant wind region and compare this to the present understanding of single star conditions where low temperature, dust and molecule forming, circumstellar envelopes prevail. (Only EG And observations are included in this file) Title: Winds and Chromospheres of Cool Luminous Stars -- Cycle 1 Authors: Carpenter, Kenneth Bibcode: 1990hst..prop.3212C Altcode: The goals of this program are to determine the physical characteristics of the winds/chromospheres around cool luminous stars. GHRS observations of the C II (UV 1) 1335 A and (UV 0.01) 2325 A multiplets will be used along with observations of the C I lines near 1655 and 1994 A to constrain the temperatures and densities in model chromospheres. The C II (UV 0.01) lines will also be used to estimate the turbulence in these chromospheres. The (confusing) far UV spectrum of the M supergiants will be explored with the GHRS. GHRS observations of Fe II lines will be used to study the dependence of the wind velocity on radial distance above the photosphere. High quality Fe II and Mg II profiles will be acquired to search for discrete velocity features and the presence of circumstellar absorption within the profiles. The photospheric absorption-line spectrum (2579-2675 A) of Arcturus will be observed in the echelle mode. Medium resolution observations of Fe II and Mg II in the dusty, very luminous star Mu Cep will provide information on the effect of dust and very low gravity on the wind velocity field. *** this file contains the Cycle 1 observations only *** Title: The First GHRS Spectra of a Cool Star: The Chromosphere of Alpha Tau Authors: Carpenter, K.; Robinson, R.; Ebbets, D.; Linsky, J.; Walter, F.; Wahlgren, G.; Ake, T. Bibcode: 1990BAAS...22.1277C Altcode: No abstract at ADS Title: On the disappearance of OI in some high-luminosity cool stars Authors: Carpenter, K. G.; Norman, D.; Robinson, R.; Fernandez-Villacanas, J. L.; Jordan, C.; Judge, P. Bibcode: 1990ESASP.310..307C Altcode: 1990eaia.conf..307C No abstract at ADS Title: Toward Mapping the Ultraviolet Circumstellar Shells of Late-Type Stars Authors: Stencel, Robert E.; Judge, Philip G.; Carpenter, Kenneth G. Bibcode: 1990ASPC....9..467S Altcode: 1990csss....6..467S Detection of spatially resolved circumstellar matter surrounding selected cool stars, using off-source observations made with the International Ultraviolet Explorer satellite, is reported. The data demonstrate that: (1) the instrumental scattered light profile of IUE appears to depend on the ultraviolet color temperature of the star observed, and (2) certain red stars show signal in excess of the instrumental levels, at spatial offsets of 10 to 20 arc-seconds from the star. Title: Modeling the Ultraviolet Photospheric Spectrum of Cool Giant Stars - Part Two - Gamma-Crucis Authors: Wahlgren, G. M.; Carpenter, K. G. Bibcode: 1990ASPC....9...67W Altcode: 1990csss....6...67W No abstract at ADS Title: Modeling the ultraviolet photospheric spectrum of cool giant stars. II. Gamma Crucis. Authors: Wahlgren, G. M.; Carpenter, K. G. Bibcode: 1990ASPC....9...65W Altcode: The authors present here some results of modeling the spectrum of the M-giant star γ Cru using similar techniques as those in their study of Arcturus (Carpenter and Wahlgren, 1990 - see Abstr. 52.114.89). Title: Modeling the Ultraviolet Photospheric Spectrum of Cool Giant Stars - Part One - Arcturus Authors: Carpenter, Kenneth G.; Wahlgren, Glenn M. Bibcode: 1990ASPC....9...64C Altcode: 1990csss....6...64C The UV photospheric spectra of cool giants are modeled analytically to facilitate the identification of UV spectral features and aid in the measurement of actual chromospheric flux at different wavelengths. Atomic line data derived experimentally and semiempirically are used with LTE model atmospheres by means of the SYNTHE FORTRAN code to generate the synthetic spectra. Surface flux spectra are determined and fitted to the absorption features of observed IUE high resolution spectra, and the modeled results are compared to the observed spectra of the cool giants Arcturus and the cooler Gamma Crucis. It is shown that the synthetic spectra can be produced for the stars, and chromospheric emission lines are thought to account for significant discrepancies between observed and calculated values. Two new fluorescence mechanisms are identified by modeling the ultraviolet photospheric spectrum of Gamma Crucis. Title: Modeling the UV Photospheric Spectrum of K-M Giant Stars Authors: Carpenter, K.; Wahlgren, G. Bibcode: 1989BAAS...21Q1112C Altcode: No abstract at ADS Title: Evidence for a Cool Wind from the K2 Dwarf in the Detached Binary V471 Tauri Authors: Mullan, D. J.; Sion, E. M.; Bruhweiler, F. C.; Carpenter, K. G. Bibcode: 1989ApJ...339L..33M Altcode: Evidence for mass loss from the K2 dwarf in V471 Tauri is found in the form of discrete absorption features in lines of various elements (Mg, Fe, Cr, Mn) and ionization stages (Mg I, Mg II, Fe I, Fe II). Resonant Mg II absorption indicates a mass loss rate of at least 10 to the -11th solar masses per year. The wind appears to be cool (no more than a few times 10,000 K). Title: Fluorescence in the Outer Atmospheres of Red Giant Stars Authors: Carpenter, K. G. Bibcode: 1989eprg.proc..372C Altcode: 1989IAUCo.106..372C No abstract at ADS Title: Far-UV Low Resolution Spectroscopy of High Luminosity K and M Stars Authors: Carpenter, Kenneth G. Bibcode: 1989iue..prop.3391C Altcode: We propose the acquisition of SWP low resolution spectra of K - M bright giants and supergiants to allow us to: 1) determine the underlying cause of the extreme weakness of certain fluorescent features, e.g. O I (UV 2), in the spectrum of a minority of such stars, 2) extend our emission measure analysis, and thus place improved constraints on the distribution of the emitting chromospheric plasma with temperature and density, to lower gravity, cooler effective temperatures, and 3) estimate the mean relative intensities of the Lyman-alpha and Lyman Beta lines within the stellar chromospheres. Used in conjunction with archival data, these spectra will also allow us to determine: 4) the dependence of radiative loss rates from cool star chromospheres on Teff and luminosity, 5) whether there is a gradual shift in the relative importance, to the chromospheric cooling, of higher and lower temperature species as we go to cooler and more luminous stars, and 6) whether there is a general trend of increasing flux in fluorescent species with decreasing effective temperature and increasing luminosity. In addition, these now spectra will be very valuable in optimizing the choice of such objects to be observed at higher resolution and higher signal/noise with the Hubble Space Telescope. Title: Short Timescale Variations in the Outer Atmosphere of Gamma Crucis Authors: Carpenter, Kenneth G. Bibcode: 1989iue..prop.3390C Altcode: We propose the acquisition of a series of UV spectra of the M-giant Gamma Cru to search for short timescale (i.e. 1 - 10 day) variations in the chromosphere and UV spectrum of the star. Our primary probes will be the numerous Fe II lines seen throughout the 2200 - 3200 A region, along with the Mg II h and k lines and the C II (UV 0.01) intercombination lines. High resolution line profiles and accurate fluxes will provide a comprehensive probe of the state (density, temperature) and stability (velocity field) of the outer atmosphere. The C II lines will be used to monitor changes in the electron density, while the behavior of the Fe II and Mg II lines can be used to study changes in the velocity of the wind versus radius and time. The outward motion of any chromospheric event will be followed by examining Fe II lines of differing optical depths, and thus differing formation heights, in the time series. Any detected variations will provide valuable clues toward understanding the excitation mechanism(s) of individual Fe II lines, and especially aid our attempts to distinguish lines dominated by photo-excitation processes (e.g. Lyman-alpha/Fe II fluorescence) from those primarily excited by collisions. This latter work will support the goals of 2 major ADP program submitted in the current proposal cycle. Title: The winds of high luminosity late-type bright stars Authors: Stencel, Robert E.; Carpenter, K. G. Bibcode: 1989gsfc.reptQ....S Altcode: The occurrence and characteristics of the Fe II line asymmetries were studied to determine the radial dependence of the wind velocity for each star. The dependence of the Fe II profiles on spectral type and luminosity class and thus the variation of the velocity fields with stellar type was also investigated. This allows the generality of the results reported for alpha Ori by Carpenter (1984b) to be judged. In addition, new atomic data was used along with observations of the C II (UV 0.01) multiplet to estimate Ne in the stellar winds. Measures of relative Fe II fluxes can be used in a probability-of-escape model to determine the opacity and hydrogen column density versus height in the chromosphere of each star. Finally, analysis of the fluorescent Fe II lines (pumped by Ly alpha) near 2507 A will yield estimates of the intrinsic stellar Ly alpha flux that cannot be measured directly because of interstellar and circumstellar absorption. One important goal of the effort was to acquire high resolution spectra of the whole 2300 to 3200 A region of 13 luminous K and M stars as a data base that will be enormously valuable in planning observations with the Hubble Space Telescope High Resolution Spectrograph. It is also proposed to follow up the recent discovery of significant variations in the Fe II chromospheric emission line profiles from the M-giant Gamma Cru for the purpose of determining the underlying cause of the variations. Title: The Ultraviolet Spectrum of Noncoronal Late-Type Stars: The Gamma Crucis (M3.4 III) Reference Spectrum Authors: Carpenter, Kenneth G.; Pesce, Joseph E.; Stencel, Robert E.; Brown, Alexander; Johansson, Sveneric; Wing, Robert F. Bibcode: 1988ApJS...68..345C Altcode: A guide is presented to the UV spectrum of M-type giants and supergiants whose outer atmospheres contain warm chromospheres but not coronae. The M3 giant Gamma Crucis is taken as the archetype of the cooler, oxygen-rich, noncoronal stars. Line identifications and integrated line flux measurements of the chromospheric emission features seen in the 1200-3200 A range of IUE high-resolution spectra are presented. The major fluorescence processes operating in the outer atmosphere of Gamma Crucis, including eight previously unknown pumping processes and 21 new fluorescent line products, are summarized, and the enhancements of selected line strengths by 'line leakage' is discussed. A set of absorption features toward the longer wavelength end of this range is identified which can be used to characterize the radial velocity of the stellar photospheres. The applicability of the results to the spectra of noncoronal stars with different effective temperatures and gravities is discussed. Title: V471 Tauri Authors: Sion, E. M.; Bruhweiler, F. C.; Carpenter, K.; Mullan, D. J. Bibcode: 1988IAUC.4667....2S Altcode: 1988IAUC.4667....0S E. M. Sion, Villanova University; F. C. Bruhweiler, Catholic University of America; K. Carpenter, Goddard Space Flight Center, NASA; and D. J. Mullan, Bartol Research Institute, report: "IUE High-Resolution SWP and LWP spectra of the Hyades member V471 Tau (an eclipsing-spectroscopic, pre-cataclysmic, close binary having spectral types K2 V + DA2) reveal very-high-velocity, cool, expanding gas (Fe II, Si II, C II, Mg II, O I), along the line-of-sight to the binary system, with an expansion velocity of -1200 km/s. There is no variation of the co-added absorption feature with orbital phase and its equivalent width is 0.035 nm, with FWHM = 30 km/s. The absorption appears in seven lines of the Fe II uv1 multiplet (258.5-261.7 nm), co-added in velocity space for each of the 11 LWP images around the orbit, in co-added LWP velocity plots of Mg II, Mn II, and Cr II, as well as in SWP plots of C II (133.5 nm), Si II (126.0 nm), and O I (130.2 nm), co-added in velocity space. This feature very likely has an origin distinct from the persistent lower velocity (-500, -260 km/s) absorption components of the K2 V stellar wind discovered by Mullan et al. (1988, ESA SP-281, p. 378; Ap.J. Letters, submitted) and from the narrow co-added feature of C II, Si II, and O I, at -590 km/s discovered by Bruhweiler and Sion (1986, Ap.J. 202, L45). The large expansion velocity suggests the possibility of its association with an ancient nova outburst. Further observations in other wavelength regions, including deep CCD imaging and direct photography, are strongly urged." Title: Detection of a Cool Wind From the K Dwarf in V471 Tauri Authors: Mullan, D. J.; Sion, E. M.; Bruhweiler, F.; Carpenter, K. Bibcode: 1988BAAS...20..997M Altcode: No abstract at ADS Title: The Far-UV Spectrum of K and M Supergiant Stars Authors: Carpenter, K. G. Bibcode: 1988BAAS...20..995C Altcode: No abstract at ADS Title: V471 Tauri: The Oldest and Nearest Old Nova? Authors: Sion, E. M.; Bruhweiler, F. C.; Carpenter, K.; Mullan, D. J. Bibcode: 1988BAAS...20S1021S Altcode: No abstract at ADS Title: What does C II lambda 2355 A emission tell us about chromospheres of red supergiants ? A critical test using dzeta Aurigae-type K supergiants. Authors: Schroeder, K. -P.; Reimers, D.; Carpenter, K. G.; Brown, A. Bibcode: 1988A&A...202..136S Altcode: Line fluxes and intensity ratios of the C II UV 0.01 intercombination multiplet near λ2325 Å have been used by Carpenter et al. (1985) to determine the density and the geometric extent of red giant chromospheres. Here the authors test the limitations of the C II method and the validity of the assumptions inherent in the method by means of observations of C II 2325 Å emission of two stars (K type supergiants ζ Aurigae, 32 Cygni) for which spatially resolved, empirical model chromospheres has been derived earlier from high resolution IUE observations at chromospheric eclipse phases (Schröder, 1985). Title: Fluorescence processes and line identifications in the UV spectra of cool stars (Contributed paper) Authors: Carpenter, Kenneth G.; Johansson, Sveneric Bibcode: 1988ESASP.281a.349C Altcode: 1988uvai....1..349C; 1988duvb.conf..349C Fluorescence processes active in the outer atmospheres of noncoronal cool stars and the UV lines they produce are summarized. Eight pumping processes and 21 fluorescent line products are discussed. The processes, which produce 12 lines, involves energy levels not previously known to be radiatively populated. Four of these are examples of self-fluorescence, whereby one or more lines of Fe II photo-excite through coincident lines the upper levels of other Fe II lines lines seen in emission, while two others explain the selective excitation of solitary Ni II and Si I lines. Nine of the line products are decays from levels in Fe I and Fe II already known to be radiatively populated. Title: Identification of new fluorescence processes in the UV spectra of cool stars from new energy levels of FeII and CrII Authors: Johansson, Sveneric; Carpenter, Kenneth G. Bibcode: 1988ESASP.281a.361J Altcode: 1988IUE88...1..361J; 1988uvai....1..361J Two fluorescence processes operating in atmospheres of cool stars, symbiotic stars, and the Sun are presented. Two emission lines, at 1347.03 and 1360.17 A, are identified as fluorescence lines of Cr II and Fe II. The lines are due to transitions from highly excited levels, which are populated radiatively by the hydrogen Lyman alpha line due to accidental wavelength coincidences. Three energy levels, one in Cr II and two in Fe II, are reported. Title: Direct UV observations of the circumstellar envelope of alpha Orionis. Authors: Stencel, R. E.; Carpenter, K. G.; Pesce, J. E.; Skinner, S.; Brown, A.; Judge, P. Bibcode: 1988ESASP.281a.249S Altcode: 1988uvai....1..249S; 1988IUE88...1..249S Observations were made in the IUE LWP camera, low dispersion mode, with alpha Ori being offset various distances from the center of the Long Wavelength Large Aperture along its major axis. Signal was acquired at all offset positions and is comprised of unequal components of background/dark counts, telescope-scattered light, and scattered light emanating from the extended circumstellar shell. The star is known from optical and infrared observations to possess an extended, arc-minute sized, shell of cool material. Attempts to observe this shell with the IUE are described, although the deconvolution of the stellar signal from the telescope scattered light requires further calibration effort. Title: The Goddard High Resolution Spectrograph for the Hubble Space Telescope: Pre-Launch Status Authors: Brandt, J.; Ebbets, D.; Carpenter, K.; Heap, S. Bibcode: 1988BAAS...20..677B Altcode: No abstract at ADS Title: Space telescope and the Fe II problem Authors: Carpenter, Kenneth G. Bibcode: 1988ASSL..138..323C Altcode: 1988IAUCo..94..323C; 1988pffl.proc..323C The capabilities of the Hubble Space Telescope, especially as they apply to the "Fe II problem" are reviewed. The major spectroscopic observing modes of both the Faint Object Spectrograph and the High Resolution Spectrograph are discussed and compared with those of the IUE satellite, with a detailed illustrative look at the options available for observations of Fe II (UV 1) near 2600 Å. Finally, the major impacts to be expected on astrophysical investigations of Fe II from the Space Telescope and associated instrumentation are summarized. Title: Dinosaur Bone Beds and Mass Mortality: Implications for the K-T Extinction Authors: Carpenter, K. Bibcode: 1988LPICo.673...24C Altcode: No abstract at ADS Title: Far-UV Low Resolution Spectroscopy of M Supergiants Authors: Carpenter, Kenneth G. Bibcode: 1988iue..prop.3079C Altcode: We propose the acquisition of SWP low resolution spectra of two M supergiants. Our emission measure analysis which derive approximate structure models of the outer atmospheric layers will be extended to lower gravity, cooler effective temperatures with these data. In combination with archive data, these spectra will be used to determine: 1) the dependence of radiative loss rates from cool star chromospheres on Teff and luminosity, 2) whether there is a gradual shift in the relative importance, to the chromospheric cooling, of higher and lower temperature species as we go to cooler and more luminous stars, 3) whether there is a general trend of increasing flux in fluorescent species with decreasing effective temperature and increasing luminosity and 4) whether the weakness of specific fluorescent lines in Alpha Ori is a general characteristic of M supergiants or is unique to Alpha Ori. In addition, these new spectra will be very valuable in optimizing the choice of such objects to be observed at higher resolution and higher signal/noise with the Hubble Space Telescope. Title: Fe II emission line profiles in the ultraviolet spectrum of cool, luminous stars Authors: Carpenter, Kenneth G. Bibcode: 1988ASSL..138...95C Altcode: 1988IAUCo..94...95C; 1988pffl.proc...95C The differences between the outer atmospheres of the coronal and noncoronal cool stars and the importance of massive stellar winds to the latter group are summarized. The utility of Fe II as a probe of such winds is indicated and a brief review of previous observations of Fe II in these stars is given. The early results of a current IUE program to study the chromospheres and winds of the noncoronal, late-type stars are presented, including evidence of a strong dependence of the mid-UV Fe II profiles on stellar luminosity. In addition, the dependence of the Fe II profiles on intrinsic line strength in spectra of Alpha Ori and the discovery of a variation of the Fe II profiles with time in spectra of Gamma Cru are discussed. Title: Emission Line Variations in the UV Spectrum of Gacrux Authors: Carpenter, K. G. Bibcode: 1987BAAS...19.1026C Altcode: No abstract at ADS Title: Observaciones con IUE e IRAS de gigantes y supergigantes rojas. Authors: Hagen, W.; Carpenter, K. G.; Stencel, R. E. Bibcode: 1987RMxAA..14..380H Altcode: . Previous observations of M giants and supergiants have indicated that chromospheric Ca II,H and K emission is lacking in stars with high circumstellar dust-to-gas ratios (Hagen, Stencel, and Dickinson 1983, Ap. J., 274, 286). Observations with lUE detected other chromospheric lines (e.g., Mg II, Al II, Fe II) in stars without Ca II emission, indicating that the dust does not completely quench the . However, line intensities in dusty stars were reduced. (Carpenter, Stencel, and Hagen 1986, Ap. J., 308, 859). IRAS observations of visually bright M giants and supergiants and simple dust shell models indicate that the 60 and lO0 m excesses can be satisfactorily explained by silicate grains. Examination of individual IRAS scans indicates spatially extended emission for the stars R Dor,aOri, W Hya, a Sco, AH Sco, R Lyr, Cep, PZ Cas and L2 Pup at 60 m. Kay : STARS-CIRCUMSTELLAR SHELLS - STARS-CHROMOSPHERES Title: The Goddard High Resolution Spectrograph for the Hubble Space Telescope Status June 1987 Authors: Brandt, J.; Heap, S.; Carpenter, K.; Ebbets, D.; Lindler, D. Bibcode: 1987BAAS...19..757B Altcode: No abstract at ADS Title: A Roadmap to the Ultraviolet Spectrum of Cool, Non-Coronal Stars Authors: Carpenter, K. G.; Peace, J.; Stencel, R. E.; Brown, A. Bibcode: 1987BAAS...19..705C Altcode: No abstract at ADS Title: 119 Tau Authors: Carpenter, Kenneth Bibcode: 1987iue..prop.2919C Altcode: No abstract at ADS Title: Variations in the Chromosphere and Stellar Wind of Gamma Crucis Authors: Carpenter, Kenneth G. Bibcode: 1987iue..prop.2752C Altcode: We propose to follow up the recent discovery of significant variations in the Fe II chromospheric emission line profiles from the M-giant Gamma Cru for the purpose of determining the underlying cause of the variations. The star will be observed at five different times during the year with SWP low resolution and LWPHI and LWPLO resolution to determine whether the apparent increase in the opacity of the stellar wind and chromosphere is: 1) due to additional mass being added to the outer atmosphere through a one-time ejection of mass or an increase in the mass loss rate, or 2) due to a temporary or permanent increase in the chromospheric heating rate, or 3) is a periodic effect due, for example, to rotation and the resulting variable visibility of inhomogeneities in the chromosphere. This star is the first single, non-Mira M-giant for which there is clear evidence from UV lines of substantial chromospheric variation. It is important that we monitor the development of this event and attempt to understand its origin, while the capabilities of IUE are still available to us. Title: Mg II Emission Lines in the Spectra of Cool, High Luminosity Stars Authors: Carpenter, Kenneth G.; Stencel, Robert E.; Pesce, Joseph E. Bibcode: 1987LNP...291..164C Altcode: 1987LNP87.291..164C; 1987csss....5..164C We present the initial results of a survey of the Mg II emission lines in the spectra of K and M giants, bright giants, and supergiants. Profiles of the Mg II h and k lines in 12 such stars are shown in a relative spectral type/luminosity class grid. Plots based on the h-line data illustrate the existence of a Wilson-Bappu. effect in these lines and of a slight dependence of the line asymmetry on V-R color. A time series of Mg II profiles for the M3 giant Gamma Cru show that the Mg II profiles have not undergone the profile shape changes seen in the Fe II lines from this star over the same time period. Title: Corrected observed stellar Lyman Alpha profiles for the effects of interstellar absorption and geocoronal emission Authors: Neff, J. E.; Linsky, J. L.; Landsman, W. B.; Carpenter, K. G. Bibcode: 1986ESASP.263..669N Altcode: 1986NIA86......669N; 1986niia.conf..669N Techniques to compensate for interstellar absorption and geocoronal emission in IUE studies of late stars atmospheres were developed. Thus it is possible to determine the Lyman alpha flux from nearby cool stars using the low-resolution spectra in the IUE archives. The accuracy of such a procedure depends fundamentally upon the assumptions regarding the shape of the intrinsic profile and the density and velocity structure of the local interstellar medium, not upon measurement uncertainties of the low-resolution spectra. Geocoronal emission and saturated spectra are fatal only to a one-dimensional spectral analysis. When both the spatial and the spectral dimensions are considered, the observed Lyman alpha flux can be recovered. Title: Current Status of the High Resolution Spectrograph (HRS) for the Hubble Space Telescope Authors: Brandt, J. C.; Carpenter, K. G.; Ebbets, D.; Garner, H.; Heap, S.; Lindler, D. Bibcode: 1986BAAS...18..940B Altcode: No abstract at ADS Title: Thermal Vacuum Test Results for the Hubble Space Telescope High Resolution Spectrograph: II. Scientific Performance Authors: Ebbets, D.; Garner, H.; Carpenter, K. G.; Brandt, J. C.; Heap, S.; Lindler, D. Bibcode: 1986BAAS...18..940E Altcode: No abstract at ADS Title: Ultraviolet and Infrared Observations of Stars with ``Quenched'' Chromospheres and the Nature of Mass Loss Authors: Stencel, R. E.; Carpenter, K. G.; Hagen, W. Bibcode: 1986ApJ...308..859S Altcode: Previous observational evidence implies that the presence of Ca II emission, a chromospheric indicator, is correlated with the gas/dust ratio in the envelopes of red giant and supergiant stars. An attempt is made to determine whether this correlation can be generalized to all chromospheric activity indicators and the gas/dust ratio. New ultraviolet observations address the strength of UV emission features and the fraction of the total chromospheric flux emitted in various lines. Evidence is found that chromospheres are not completely quenched in the presence of dust, but that significant alteration of relative radiative loss patterns may occur. These observations are interpreted in terms of an instability that converts warm, chromospheric gas into near-surface dust grains and cool gas capable of supporting molecular masing. This supports the dust-driven mass loss scenario for red giant winds. Title: Thermal Vacuum Test Results for the Hubble Space Telescope High Resolution Spectrograph: I. UV Optical Throughput Authors: Carpenter, K. G.; Ebbets, D.; Garner, H.; Heap, S.; Lindler, D.; Brandt, J. C. Bibcode: 1986BAAS...18..940C Altcode: No abstract at ADS Title: Mg II Emission Line Variability of Hybrid Chromosphere Stars Authors: Brown, A.; Linsky, J. L.; Drake, S. A.; Carpenter, K. G. Bibcode: 1986BAAS...18S.983B Altcode: No abstract at ADS Title: FeII emission line profiles in spectra of high luminosity, non-coronal stars Authors: Carpenter, K. G. Bibcode: 1986ESASP.263...99C Altcode: 1986NIA86.......99C; 1986niia.conf...99C The results of a program to study the winds of noncoronal late-type giant and supergiant stars with IUE are presented. The primary data for this study are profiles, fluxes, and velocities of the Fe II emission lines which occur throughout the 2200 to 3230 A region of the IUE long wavelength spectrographs. The apparent dependence of the Fe II profiles on stellar luminosity (surface gravity) and intrinsic line strength is discussed. The discovery of significant changes in the Fe II profiles in spectra of Gamma Crucis (M3 III), during the period 1978 to 1985, that suggest a substantial change in its outer atmosphere is noted. Title: An IUE High-Dispersion Cool-Star Atlas Authors: Ayres, T. R.; Brugel, E. W.; Linskyl, J. L.; Brown, A.; Carpenter, K. G. Bibcode: 1986LNP...254..106A Altcode: 1986csss....4..106A We are planning to compile a spectral atlas based on high-dispersion images of representative late-type stars recorded by the International Ultraviolet Explorer. We solicit advice from the ultraviolet community concerning how best to present the spectral material. Title: Gamma Crucis Authors: Carpenter, Kenneth Bibcode: 1986iue..prop.2633C Altcode: No abstract at ADS Title: Optical, UV and Radio Observations of RS Canum Venaticorum Authors: Catalano, S.; Rodono, M.; Linsky, J. F.; Carpenter, K.; Gibson, D.; Gary, D.; Butler, J. Bibcode: 1986LNP...254..253C Altcode: 1986csss....4..253C No abstract at ADS Title: IUE and IRAS observations of luminous M stars with varying gas-to-dust ratios. Authors: Hagen, W.; Carpenter, K. G.; Stencel, R. E. Bibcode: 1986NASCP2403A...8H Altcode: No abstract at ADS Title: The Winds of High Luminosity K and M Stars Authors: Carpenter, Kenneth G. Bibcode: 1986iue..prop.2426C Altcode: The winds of high luminosity K and M stars likely play a major role in stellar evolution, yet this region of the H-R diagram is one of the least-studied with IUE, due to the very limited number of targets that are bright in the ultraviolet. However, high-resolution spectra of the long wavelength region of the few well-observed stars reveal extremely interesting spectra containing dozens of broad, frequently self-reversed and asymmetric Fe II emission lines in addition to the Mg II, Al II, and C II lines seen in all late-type stars. We propose a comprehensive study of a sample of 13 such stars using both archive and new observations. We shall study the occurrence and characteristics of the Fe II line asymmetries to determine the radial dependence of the wind velocity for each star. We shall also investigate the dependence of the Fe II profiles on spectral type and luminosity class and thus the variation of the velocity fields with stellar type. This will allow us to judge the generality of the results reported for alpha Ori by Carpenter (1984b). In addition, we shall use new atomic data along with observations of the C II(UV 0.01) multiplet to estimate Ne in the stellar winds. Measures of relative Fe II fluxes will be used in a probability-of-escape model to determine the opacity and hydrogen column density versus height in the chromosphere of each star. Finally, analysis of the fluorescent Fe II lines (pumped by Ly-alpha) near 2507 will yield estimates of the intrinsic stellar Ly-alpha flux that cannot be measured directly because of interstellar and circumstellar absorption. One important goal of this proposal is to acquire high resolution spectra of the whole 2300-3200 A region of 13 luminous K and M stars as a data base that will be enormously valuable in planning observations with the Space Telescope High Resolution Spectrograph, which will be able to observe only small portions of the spectrum at one time with high sensitivity. Title: Efficiency functions for a 316 g/mm echelle grating. Authors: Cushman, G. W.; Carpenter, K. G. Bibcode: 1986SPIE..627..395C Altcode: The radiometric response function of the High Resolution Spectrograph (HRS) for the Hubble Space Telescope was measured in 1984. From the system efficiency measurements made in the HRS echelle modes, the relative efficiencies ('ripple' functions) of 14 HRS echelle orders have been deduced. The results agree well with a theoretical model of echelle efficiency, except for a residual shift of apparent blaze angle with spectral order. The discrepancy between nominal and fitted blaze angle decreases with increasing order number. Title: The Effect of Dust on the Chromospheres of Cool, Luminous Stars Authors: Carpenter, K. G.; Stencel, R. E.; Hagen, W. Bibcode: 1985BAAS...17..876C Altcode: No abstract at ADS Title: Hydrogen Lyman Alpha Fluxes for Late-Type Dwarf Stars Authors: Neff, J. E.; Carpenter, K. G.; Ayres, T. R. Bibcode: 1985BAAS...17..879N Altcode: No abstract at ADS Title: Densities, Temperatures and Geometric Extents of C II Emitting Regions in the Winds of Luminous, Late-Type Stars Authors: Carpenter, K. G.; Brown, A.; Stencel, R. E. Bibcode: 1985mlrg.proc...55C Altcode: The authors summarize techniques for using IUE observations of the C II UV 0.01 and UV 1 emission line multiplets at 2325 Å and 1335 Å to estimate the electron density (Ne) and temperature (Te) in, and the geometric extent of, the chromospheres of late-type stars. The results of applying these techniques to a sample of 15 stars observed with the IUE satellite are discussed. Title: Emission Line Variability of RY Tau, DR Tau and SU Aur Authors: Brown, A.; Walter, F. M.; Carpenter, K. G.; Jordan, C.; Judge, P. Bibcode: 1985BAAS...17..556B Altcode: No abstract at ADS Title: Laboratory Calibration of the High Resolution Spectrograph for Space Telescope: Absolute Sensitivity Authors: Carpenter, K. G.; Cushman, G.; Ebbets, D.; Heap, S.; Brandt, J. Bibcode: 1985BAAS...17..574C Altcode: No abstract at ADS Title: Line identifications, line strengths and continuum flux measurements in the ultraviolet spectrum of Arcturus. Authors: Carpenter, K. G.; Wing, R. F.; Stencel, R. E. Bibcode: 1985ApJS...57..405C Altcode: The ultraviolet spectrum of Arcturus has been observed at high resolution with the IUE satellite. Line identifications, mean absolute 'continuum' flux measurements, integrated absolute emission-line fluxes, and measurements of selected absorption line strengths are presented for the 2250-2930 A region. In the 1150-2000 A region, identifications are given primarily on the basis of low-resolution spectra. Chromospheric emission lines have been identified with low-excitation species including H I, C I, C II, O I, Mg I, Mg II, Al II, Si I, Si II, S I, and Fe II; there is no evidence for lines of C IV, N V, or other species requiring high temperatures. A search for molecular absorption features in the 2500-2930 A interval has led to several tentative identifications, but only OH could be established as definitely present. Iron lines strongly dominate the identifications in the 2250-2930 A region, Fe II accounting for about 86 percent of the emission features and Fe I for 43 percent of the identified absorption features. Title: The geometric extent of C II (UV 0.01) emitting regions around luminous, late-type stars Authors: Carpenter, K. G.; Brown, A.; Stencel, R. E. Bibcode: 1985ApJ...289..676C Altcode: A method is presented by which the geometric extent of the chromospheres around late-type stars can be estimated from measurements of the total emission-line flux and line ratios within the C II (UV 0.01) multiplet. Application of this technique to a sample of 15 late-type stars indicates a clear difference in the radial extent of the chromospheres around coronal and noncoronal stars. The former stars appear to have very thin chromospheres (of no more than 0.1 percent of the photospheric radius), while the latter stars have chromospheres extending, on average, out to 2.5 photospheric radii. This, in principle, provides information for understanding structural differences between late-type giant and supergiant stars with and without coronae, and could lead to an understanding of the mass-loss mechanisms involved. Title: The structures and spectra of magnetic, line-blanketed model atmospheres Authors: Carpenter, K. G. Bibcode: 1985ApJ...289..660C Altcode: Magnetic, line-blanketed model atmospheres for upper-main-sequence stars with normal elemental abundances and a slightly distorted dipolar magnetic field have been constructed. These were computed with a modified version of the Kurucz ATLAS6 model atmosphere code and newly computed opacity distribution functions (ODFs), which take into account the Zeeman splitting of the contributing atomic lines. The inclusion of magnetic forces changes the structure of an atmosphere by altering the net gravity and thus the pressure distribution in the upper layers of the atmosphere. These magnetic forces cause the structure of the stellar model to vary with latitude and to differ from the nonmagnetic case. The enhanced blanketing represented by the 'magnetic' ODFS in combination with the structure changes and Zeeman broadening of individual lines causes the emergent spectrum to vary with viewing inclination and to differ from the nonmagnetic case. The structure and spectrum computations are described and results compared with those for nonmagnetic models. The results are discussed in light of existing observations of Ap stars, which are thought to have magnetic field configurations similar to the ones included in these models. Title: The temperature of C II emission-line formation regions in cool stars. Authors: Brown, A.; Carpenter, K. G. Bibcode: 1984ApJ...287L..43B Altcode: An investigation has been conducted of the temperature of C II emission-line formation regions in the outer atmospheres of late-type giant and supergiant stars. A distinct dichotomy is seen in the C II lambda 2325/lambda 1335 ratio between coronal and noncoronal stars. It is found that C II emission from noncoronal giant and supergiant stars comes from regions with temperatures of 7000-9000 K, with the mean temperature being approximately 8500 K, whereas the C II emission from coronal stars likely comes from hotter regions. The C II ratio provides a powerful empirical tool for estimating the chromospheric temperatures of cool giants and supergiants. Title: Chromospheric emission lines in high-resolution LWR spectra (2200 - 3000 Å) of Gamma Cru (M3 III) and Alpha Ori (M2 Iab). Authors: Carpenter, K. G. Bibcode: 1984NASCP2349..450C Altcode: 1984fiue.rept..450C; 1984IUE84......450C The identity and characteristics of the chromospheric emission features in the 2200 to 300 A region of high resolution spectra of the stars gamma Cru and alpha Ori are summarized. The velocities, fluxes, and asymmetries of a set of Fe II lines which share common upper or lower energy levels are discussed and the information gained from flux measurements of the C II (UV 0.01) lines is presented. The Fe II lines in the alpha Ori spectra indicate the general shape of the velocity versus radius relation in its wind. The C II (UV 0.01) data are combined with measures of the C II (UV 1) flux to estimate the electron density and temperature in the wind and the geometric extent of the C II emitting region in both stars. Title: A progress report on the analysis of long exposure SWP high resolution spectra of cool stars. Authors: Linsky, J. L.; Ayres, T. R.; Brown, A.; Carpenter, K.; Jordan, C.; Judge, P.; Gustafsson, B.; Eriksson, K.; Saxner, M.; Engvold, O.; Jensen, E.; Moe, O. K.; Simon, T. Bibcode: 1984NASCP2349..445L Altcode: 1984fiue.rept..445L; 1984IUE84......445L The IUE is the first experiment with sufficient sensitivity to obtain high resolution spectra (lambda/delta lambda is approximately 10,000) of many cool stars in the vitally important 1200 to 2000 A spectral region. These data provide qualitatively new information with which to understand the properties of and structures in the outer atmospheres of these stars. Also, these cool star spectra will be extremely useful in planning for the Space Telescope High Resolution Spectrograph, which will be 1000 times more sensitive than IUE but will be hampered by limited observing time and limited spectral bandwidth in each exposure. Very long exposure, high disperson SWP spectra of many stars located throughout the cool half of the HR diagram were obtained. These 12 to 21 hour exposures were obtained by combining NASA and Vilspa shifts so as to obtain the longest possible exposures at times of low background. Included are dwarf stars of spectral type G0 V to M2 V, G9.5 III to M5 II giants, G2 Ib to M2 Iab supergiants, a number of RS CVn-type systems, and Barium stars. Title: Rotational velocities of later B type and A type stars as determined from ultraviolet versus visual line profiles. Authors: Carpenter, K. G.; Slettebak, A.; Sonneborn, G. Bibcode: 1984ApJ...286..741C Altcode: Theoretical line profiles of the Si III 1299 and Fe II 2756 lines are computed for rotating B5-A7 model stars, and compared with observed profiles from IUE spectra to derive rotational velocities. Real differences in widths for ultraviolet as compared with visual line profiles exist in the sample of B type stars (but not for the A type rapidly rotating stars), although these are not as large as previously reported in the literature. Comparison with the theoretical line profiles gives rotational velocities that are in good agreement with visually determined v sin i values for the same stars, which suggests that the shape-distorted, gravity-darkened models are reasonable. Title: Characteristics of the Fe II and C II emission in high-resolution IUEspectra (2300-3000 A ) of alpha Orionis. Authors: Carpenter, K. G. Bibcode: 1984ApJ...285..181C Altcode: A study is presented of Fe II and C II emission features in the 2300-3000 A region of four high-resolution IUE spectra of Alpha Ori obtained during the period 1978 April-1982 November. A set of 42 unmutilated, unblended Fe II lines of multiplets UV 1-3, 32-33, 35-36, and 60-64 and the C II (UV 0.01) intercombination lines have been identified and measured to determine their velocities, fluxes, and asymmetries. A correlation of Fe II line asymmetry with intrinsic line strength indicates a velocity field which is initially constant, then algebraically increases with radius to a maximum value and then decreases significantly before reaching an asymptotic flow speed far from the star. The mean velocity of the chromospheric regions emitting Fe II does not appear to differ substantially from the time-average of the photospheric velocity, but there is evidence that the two regions are not strongly coupled and thus that the chromosphere does not strictly follow the semiperiodic 6 year pulsations of the photosphere. An analysis of the C II line fluxes produces estimates of the electron density in the chromosphere in the range 3.2 x 10 to the 7th-1.3 x 10 to the 8th per sq cm and indicates that the region emitting C II is geometrically thick, extending at least one-tenth, and perhaps as far as 1.2, photospheric radii from the base of the chromosphere. Title: IUE and IRAS Observations of Luminous M Stars with Varying Gas-to-Dust Ratios Authors: Hagen, W.; Carpenter, K. G.; Stencel, R. E. Bibcode: 1984BAAS...16..895H Altcode: No abstract at ADS Title: Atmospheric Structures in AR Lac. I. Mapping Quiescent Features by Occultations &Doppler Imaging Authors: Walter, F. M.; Gibson, D. M.; Brown, A.; Carpenter, K.; Linsky, J. L.; Rodono, M.; Eyles, C. Bibcode: 1984BAAS...16R.896W Altcode: 1984BAAS...16..896W No abstract at ADS Title: Book-Review - Atlas of High Resolution IUE Spectra of Late-Type Stars 2500-3230A Authors: Wing, R. F.; Carpenter, K. G.; Wahlgren, G. M. Bibcode: 1984S&T....67R.527W Altcode: No abstract at ADS Title: Ultraviolet spectroscopic observations of some Be stars of later typeand A-F type shell stars. Authors: Slettebak, A.; Carpenter, K. G. Bibcode: 1983ApJS...53..869S Altcode: High-dispersion IUE spectra of 18 later type Be and A-F type shell stars as well as eight standard nonemission line stars have been analyzed for anomalous ionization and mass loss effects. It is found that superionization in the Be stars extends to the latest spectral subtypes but does not seem to be present in the A-F type stars. The superionized lines in the Be stars appear to be correlated with v sin i. Asymmetrical or violet-displaced resonance lines suggesting mass loss are observed in all the Be stars except one, in some of the standard stars, but not in the A-F stars. Lower limits to the mass loss rates computed from Si IV lines range between 5.3 x 10 to the -12th and 3.5 x 10 to the -11th solar masses/yr, with Be shell stars showing the largest values. Mass loss is correlated with luminosity and effective temperature but not with rotation. Title: Characteristics of the Fe II and C II Chromospheric Emission Lines in Alpha Ori as a Function of Time Authors: Carpenter, K. G. Bibcode: 1983BAAS...15..966C Altcode: No abstract at ADS Title: Atlas of high resolution IUE spectra of late-type stars 2500-3230 A Authors: Wing, Robert F.; Carpenter, Kenneth G.; Wahlgren, Glenn M. Bibcode: 1983ahri.book.....W Altcode: 1983QB843.C6W56.... No abstract at ADS Title: Ultraviolet spectroscopic observations of some Be stars of later typeand A-F type shell stars. Authors: Slettebak, A.; Carpenter, K. G. Bibcode: 1983BeSN....8....7S Altcode: No abstract at ADS Title: Measurements of chromospheric densities and geometrical extensions of late-type giant and super-giant stars Authors: Wing, R. F.; Carpenter, K. G.; Stencel, R. E.; Linsky, J. L. Bibcode: 1983osuc.rept.....W Altcode: The density sensitivity of the emission lines within the UV 0.01 multiplet of C II near 2325 A was examined in additional late type giants and supergiants with deep LWR high dispersion exposures. The new data support the original contention based on these lines that noncoronal red giants possess geometrically extended chromospheres. Title: A Study of Magnetic, Line-Blanketed Model Atmospheres. Authors: Carpenter, K. G. Bibcode: 1983PhDT.........2C Altcode: Magnetic, line-blanketed model atmospheres for upper main-sequence stars with normal elemental abundances and a slightly distorted dipolar magnetic field have been constructed. These were computed with a modified version of the ATLAS6 (Kurucz, 1979) model atmosphere code and newly computed Opacity Distribution Functions (ODF's), which take into account the Zeeman Splitting of the contributing atomic lines. The calculation of the "magnetic" ODF's is described and the results are compared with the original non-magnetic Kurucz functions. The inclusion of magnetic forces changes the structure of an atmosphere by altering the net gravity and thus the pressure distribution in the upper layers of the atmosphere. These magnetic forces cause the structure of the stellar model to vary with latitude and to differ from the non-magnetic case. The enhanced blanketing represented by the "magnetic" ODF's in combination with the structure changes cause the emergent spectrum to vary with viewing inclination and to differ from the non-magnetic case. The structure and spectra computations are described and results compared with those for non-magnetic models. The results are discussed in light of existing observations of Ap stars, which are thought to have magnetic field configurations corresponding to the ones included in these models. Title: A study of magnetic, line-blanketed model atmospheres Authors: Carpenter, Kenneth George Bibcode: 1983PhDT.......177C Altcode: No abstract at ADS Title: Outer atmospheres of cool stars. XII. A survey of IUE ultraviolet emission line spectra of cool dwarf stars. Authors: Linsky, J. L.; Bornmann, P. L.; Carpenter, K. G.; Wing, R. F.; Giampapa, M. S.; Worden, S. P.; Hege, E. K. Bibcode: 1982ApJ...260..670L Altcode: Quantitative information is obtained on the chromospheres and transition regions of M dwarf stars, in order to determine how the outer atmospheres of dMe stars differ from dM stars and how they compare with the outer atmospheres of quiet and active G and K type dwarfs. IUE spectra of six dMe and four dM stars, together with ground-based photometry and spectroscopy of the Balmer and Ca II H and K lines, show no evidence of flares. It is concluded, regarding the quiescent behavior of these stars, that emission-line spectra resemble that of the sun and contain emission lines formed in regions with 4000-20,000 K temperatures that are presumably analogous to the solar chromosphere, as well as regions with temperatures of 20,000-200,000 K that are presumably analogous to the solar transition region. Emission-line surface fluxes are proportional to the emission measure over the range of temperatures at which the lines are formed. Title: An Atlas of High-Resolution IUE Spectra of Late-Type Stars Authors: Wing, R. F.; Carpenter, K. G.; Wahlgren, G. M. Bibcode: 1982BAAS...14..918W Altcode: No abstract at ADS Title: Magnetic, Line-blanketed Model Atmospheres Authors: Carpenter, K. G. Bibcode: 1982BAAS...14..920C Altcode: No abstract at ADS Title: Integrated Fluxes for Emission Lines in the Ultraviolet Spectra of Several Planetary Nebulae Authors: Carpenter, K. G.; Czyzak, S. J. Bibcode: 1982Ap&SS..84..495C Altcode: The IUE satellite observatory has been used to obtain absolutely-calibrated emission line fluxes for diagnostic lines of multiply-ionized C, N, O, Si, Ne, and Ar which occur in the ultraviolet spectral region of planetary nebulae. These data, when combined with data from the blue, visual, and near infrared, will provide improved estimates of ionic concentrations, plasma temperatures and densities, and elemental abundances. Title: Fluorescence in Stellar Chromospheres Authors: Carpenter, K. G.; Wing, R. F.; Stencel, R. E. Bibcode: 1982BAAS...14..614C Altcode: No abstract at ADS Title: Density sensitive C II lines in cool giant stars. Authors: Stencel, R. E.; Carpenter, K. G. Bibcode: 1982NASCP2238..243S Altcode: 1982NASCP2338..243S; 1982auva.nasa..243S; 1982IUE82......243S The density sensitivity of the emission lines within the ultraviolet 0.01 multiplet of C II near 2325 A was examined in additional late type giants and supergiants with deep LWR high dispersion exposures. The new data support the original contention based on these lines that noncoronal red giants posses geometrically extended chromospheres. Title: Integrated fluxes for emission lines in the ultraviolet spectra of several planetaries Authors: Carpenter, K. G.; Czyzak, S. J. Bibcode: 1981STIN...8213022C Altcode: The IUE satellite observatory was used to obtain absolutely-calibrated emission line fluxes for diagnostic lines of multiply-ionized C, N, O, Si, Ne, and Ar which occur in the ultraviolet spectral region of planetary nebulae. These data, when combined with data from the blue, visual, and near infrared, provide improved estimates of ionic concentrations, plasma temperatures and densities, and elemental abundances. Title: Density sensitive C II lines in cool stars of low gravity. Authors: Stencel, R. E.; Linsky, J. L.; Brown, A.; Jordan, C.; Carpenter, K. G.; Wing, R. F.; Czyzak, S. Bibcode: 1981MNRAS.196P..47S Altcode: It is shown that the relative intensities of emission lines within the multiplet UV 0.01 of C II, around 2325 A, are sensitive to electron density in the range 10 to the 9th to 10 to the 7th per cu cm. The lines therefore offer a valuable method for measuring electron densities in the chromospheres of late-type giants and supergiants. Calculated line ratios are compared with those observed in a range of objects. Title: Notes on the early-type components of W Cep, omicron Cet, CH Cyg, AR Mon, and BL Tel. Authors: Wing, R. F.; Carpenter, K. G. Bibcode: 1981NASCP2171..341W Altcode: 1981uviu.nasa..341W; 1981NASCP3171..341W; 1980IUE80......341W Low resolution IUE spectra in both spectral regions are used to clarify the nature of the warmer components of several binary systems. The W Cep, the primary of which is a luminous K-type supergiant, shows an ultraviolet absorption spectrum of type B0 or B1; this system is heavily reddened. The hot companion of Mira (o Cet) is surprisingly faint in the short wavelength region, but it excites a rich emission spectrum from the surrounding gas. The ultraviolet active M7 giant CH Cyg is shown to be a binary with a hot companion. This system was also observed at high resolution and shows variable Fe II emission and well-separated circumstellar and interstellar absorptions within the broad Mg II emission profiles. The eclipsing binaries AR Mon and BL Tel are shown not to have hot companions. Title: A Search for Technetium in Zeta Cap and Several M star Mira Variables Authors: Little-Marenin, I. R.; Little, S. J.; Wing, R. F.; Carpenter, K. G.; Wallerstein, G. Bibcode: 1980BAAS...12..826L Altcode: No abstract at ADS Title: Chromospheric Densities and Geometrical Extensions of Red Giants and Supergiants using C II Lines as Diagnostics Authors: Stencel, R. E.; Jordan, C.; Wing, R. F.; Linsky, J. L.; Carpenter, K. G.; Brown, A.; Czyzak, S. J. Bibcode: 1980BAAS...12..806S Altcode: No abstract at ADS Title: An IUE Survey of the Ultraviolet Emission Line Spectra of dMe and dM Stars Authors: Carpenter, K. G.; Wing, R. F.; Bornmann, P. L.; Linsky, J. L. Bibcode: 1980BAAS...12..538C Altcode: No abstract at ADS Title: Extension of Line Identifications in Arcturus Shortward to 2250A Authors: Carpenter, K. G.; Stencel, R. E.; Wing, R. F. Bibcode: 1980BAAS...12..529C Altcode: No abstract at ADS Title: Survey of the Ultraviolet Spectra of Late-Type Stars Authors: Carpenter, K. G.; Wing, R. F. Bibcode: 1979BAAS...11..419C Altcode: No abstract at ADS Title: Ultraviolet Spectra of M Stars. Authors: Wing, R. F.; Carpenter, K. G. Bibcode: 1978BAAS...10..444W Altcode: No abstract at ADS Title: Intercomparisons of Parallaxes from Nine Observatories. Authors: Upgren, A. R.; Carpenter, K. G. Bibcode: 1977BAAS....9..355U Altcode: No abstract at ADS Title: An estimate of external errors in parallaxes Authors: Upgren, A. R.; Carpenter, K. G. Bibcode: 1977AJ.....82..227U Altcode: The estimate of the external errors in trigonometric paral1axes made by Hertzsprung is repeated using a nonlinear least-squares procedure to fit normal distributions to observed frequency distributions in parallaxes. The best estimate of mean error in parallax is io' 016, in exact agreement with Hertzsprung; but unlike him, it was made using only parallaxes listed in the Yale Catalogue determined at a single observatory. Using the entire catalogue as he did, an error of +0.018 was found, but the smaller value is considered more realistic. Title: Observations of the large Comet Authors: Burder, W. C.; Stothard, J. M.; Tidmarsh, G. A.; Carpenter Bibcode: 1861MNRAS..21..242B Altcode: No abstract at ADS