Author name code: worden ADS astronomy entries on 2022-09-14 author:"Worden, Simon P." OR author:"Worden, Pete" ------------------------------------------------------------------------ Title: Venus Life Finder Missions Motivation and Summary Authors: Seager, Sara; Petkowski, Janusz J.; Carr, Christopher E.; Grinspoon, David H.; Ehlmann, Bethany L.; Saikia, Sarag J.; Agrawal, Rachana; Buchanan, Weston P.; Weber, Monika U.; French, Richard; Klupar, Pete; Worden, Simon P.; Baumgardner, Darrel Bibcode: 2022arXiv220805570S Altcode: Finding evidence of extraterrestrial life would be one of the most profound scientific discoveries ever made, advancing humanity into a new epoch of cosmic awareness. The Venus Life Finder (VLF) missions feature a series of three direct atmospheric probes designed to assess the habitability of the Venusian clouds and search for signs of life and life itself. The VLF missions are an astrobiology-focused set of missions, and the first two out of three can be launched quickly and at a relatively low cost. The mission concepts come out of an 18-month study by an MIT-led worldwide consortium. Title: Benefit-Sharing as Investment Protection for Space Resource Utilization Authors: Bohacek, Petr; Worden, Simon P.; Grattan, Kyran Bibcode: 2022NewSp..10..127B Altcode: No abstract at ADS Title: Searching for Broadband Pulsed Beacons from 1883 Stars Using Neural Networks Authors: Gajjar, Vishal; LeDuc, Dominic; Chen, Jiani; Siemion, Andrew P. V.; Sheikh, Sofia Z.; Brzycki, Bryan; Croft, Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Drew, Jamie; Isaacson, Howard; Lacki, Brian C.; Lebofsky, Matt; MacMahon, David H. E.; Ng, Cherry; de Pater, Imke; Perez, Karen I.; Price, Danny C.; Suresh, Akshay; Webb, Claire; Worden, S. Pete Bibcode: 2022ApJ...932...81G Altcode: 2022arXiv220502964G The search for extraterrestrial intelligence at radio frequencies has largely been focused on continuous-wave narrowband signals. We demonstrate that broadband pulsed beacons are energetically efficient compared to narrowband beacons over longer operational timescales. Here, we report the first extensive survey searching for such broadband pulsed beacons toward 1883 stars as a part of the Breakthrough Listen's search for advanced intelligent life. We conducted 233 hr of deep observations across 4-8 GHz using the Robert C. Byrd Green Bank Telescope and searched for three different classes of signals with artificial (or negative) dispersion. We report a detailed search-leveraging a convolutional neural network classifier on high-performance GPUs-deployed for the very first time in a large-scale search for signals from extraterrestrial intelligence. Due to the absence of any signal-of-interest from our survey, we place a constraint on the existence of broadband pulsed beacons in our solar neighborhood: ≲1 in 1000 stars have transmitter power densities ≳105 W Hz-1 repeating ≤500 s at these frequencies. Title: The Breakthrough Listen Search for Intelligent Life: Technosignature Search of Transiting TESS Targets of Interest Authors: Franz, Noah; Croft, Steve; Siemion, Andrew P. V.; Traas, Raffy; Brzycki, Bryan; Gajjar, Vishal; Isaacson, Howard; Lebofsky, Matthew; MacMahon, David H. E.; Price, Danny C.; Sheikh, Sofia Z.; DeMarines, Julia; Drew, Jamie; Worden, S. Pete Bibcode: 2022AJ....163..104F Altcode: 2022arXiv220100918F The Breakthrough Listen (BL) Initiative, as part of its larger mission, is performing the most thorough technosignature search of nearby stars. Additionally, BL is collaborating with scientists working on NASA's Transiting Exoplanet Survey Satellite (TESS) to examine TESS Targets of Interest (TOIs) for technosignatures. Here, we present a 1-11 GHz radio technosignature search of 61 TESS TOIs that were in transit during their BL observation at the Robert C. Byrd Green Bank Telescope. We performed a narrowband Doppler drift search with a minimum S/N threshold of 10 across a drift rate range of ±4 Hz s-1 with a resolution of 3 Hz. We removed radio frequency interference by comparing signals across cadences of target sources. After interference removal, there are no remaining events in our survey, and therefore no technosignature signals of interest detected in this work. This null result implies that at L, S, C, and X bands, fewer than 52%, 20%, 16%, and 15%, respectively, of TESS TOIs possess a transmitter with an equivalent isotropic radiated power greater than a few times 1014 W. Title: The first deep-learning search for radio technosignatures from 820 nearby stars Authors: Ma, Xiangyuan; Ng, Cherry; Rizk, Leandro; Croft, Steve; Siemion, Andrew; Brzycki, Bryan; Isaacson, Howard; Drew, Jamie; Worden, S. Pete; Sheikh, Sofia Z.; de Pater, Imke; Gajjar, Vishal; Czech, Daniel; Lebofsky, Matt; John, Hoang; MacMahon, David; Price, Danny; Breakthrough Listen Team Team Bibcode: 2022APS..APRB09008M Altcode: The goal of the Search for Extraterrestrial Intelligence (SETI) is to quantify the prevalence of technological life beyond Earth via their ``technosignatures". One theorized technosignature is narrowband Doppler drifting radio signals. The principal challenge in conducting SETI in the radio domain is developing a generalized technique to reject human radio frequency interference (RFI) that dominates the features across the band in searches for technosignatures. Here, we will present the first comprehensive deep-learning-based technosignature search to date, returning 8 promising ETI signals-of-interest for re-observation as part of the Breakthrough Listen initiative. The search comprises 820 unique targets observed with the Robert C. Byrd Green Bank Telescope, totaling over 480hr of on-sky data. We implement a novel beta-Convolutional Variational Autoencoder with an embedded discriminator combined with Random Forest Decision Trees to classify technosignature signals of interest in a semi-unsupervised manner. We compare our results with prior classical techniques on the same dataset and conclude that our algorithm returns more convincing signals of interest with a manageable false positive rate. This novel approach presents itself as a leading solution in accelerating SETI and other transient research into the new age of data-driven astronomy.

The project was supported by the Laidlaw foundation which has funded this project as part of the undergraduate research and leadership funding initiative. Title: One of Everything: The Breakthrough Listen Exotica Catalog Authors: Lacki, Brian C.; Brzycki, Bryan; Croft, Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Gajjar, Vishal; Isaacson, Howard; Lebofsky, Matt; MacMahon, David H. E.; Price, Danny C.; Sheikh, Sofia Z.; Siemion, Andrew P. V.; Drew, Jamie; Worden, S. Pete Bibcode: 2021ApJS..257...42L Altcode: 2020arXiv200611304L We present Breakthrough Listen's Exotica Catalog as the centerpiece of our efforts to expand the diversity of targets surveyed in the Search for Extraterrestrial Intelligence (SETI). As motivation, we introduce the concept of survey breadth, the diversity of objects observed during a program. Several reasons for pursuing a broad program are given, including increasing the chance of a positive result in SETI, commensal astrophysics, and characterizing systematics. The Exotica Catalog is a 963 entry collection of 816 distinct targets intended to include "one of everything" in astronomy. It contains four samples: the Prototype sample, with an archetype of every known major type of nontransient celestial object; the Superlative sample of objects, with the most extreme properties; the Anomaly sample of enigmatic targets that are in some way unexplained; and the Control sample, with sources not expected to produce positive results. As far as we are aware, this is the first object list in recent times with the purpose of spanning the breadth of astrophysics. We share it with the community in hopes that it can guide treasury surveys and as a general reference work. Accompanying the catalog is an extensive discussion of the classification of objects and a new classification system for anomalies. Extensive notes on the objects in the catalog are available online. We discuss how we intend to proceed with observations in the catalog, contrast it with our extant Exotica efforts, and suggest how similar tactics may be applied to other programs. Title: Venus Life Finder Mission Study Authors: Seager, Sara; Petkowski, Janusz J.; Carr, Christopher E.; Grinspoon, David; Ehlmann, Bethany; Saikia, Sarag J.; Agrawal, Rachana; Buchanan, Weston; Weber, Monika U.; French, Richard; Klupar, Pete; Worden, Simon P. Bibcode: 2021arXiv211205153S Altcode: The Venus Life Finder Missions are a series of focused astrobiology mission concepts to search for habitability, signs of life, and life itself in the Venus atmosphere. While people have speculated on life in the Venus clouds for decades, we are now able to act with cost-effective and highly-focused missions. A major motivation are unexplained atmospheric chemical anomalies, including the "mysterious UV-absorber", tens of ppm O$_2$, SO$_2$ and H$_2$O vertical abundance profiles, the possible presence of PH$_3$ and NH$_3$, and the unknown composition of Mode 3 cloud particles. These anomalies, which have lingered for decades, might be tied to habitability and life's activities or be indicative of unknown chemistry itself worth exploring. Our proposed series of VLF missions aim to study Venus' cloud particles and to continue where the pioneering in situ probe missions from nearly four decades ago left off. The world is poised on the brink of a revolution in space science. Our goal is not to supplant any other efforts but to take advantage of an opportunity for high-risk, high-reward science, which stands to possibly answer one of the greatest scientific mysteries of all, and in the process pioneer a new model of private/public partnership in space exploration. Title: No Redetections of blc1 in 39 hr of Reobservation Campaigns of Proxima Centauri Authors: Sheikh, Sofia Z.; Smith, Shane; Price, Danny; Lebofsky, Matt; Siemion, Andrew; Cordes, James M.; Gajjar, Vishal; Drew, Jamie; Worden, S. Pete Bibcode: 2021RNAAS...5..248S Altcode: In 2019 April, radio observations of Proxima Centauri were performed with the Ultra-Wideband Low Receiver on the Parkes Telescope. A narrowband radio search of these data revealed a technosignature signal-of-interest reported as "blc1" at 982.002 MHz. After the initial discovery of blc1 in the data in 2020 October, we performed a series of reobservations over the next 6 months, totaling 39 hr of on-sky time. We do not redetect blc1, or find any other signals-of-interest, within ±1 MHz of 982.002 MHz in this data set. Taken in context, this null result implies that blc1 was transient radio frequency interference, makes it less consistent with a periodic transmission, and makes it less consistent with interstellar scintillation. Title: A radio technosignature search towards Proxima Centauri resulting in a signal of interest Authors: Smith, Shane; Price, Danny C.; Sheikh, Sofia Z.; Czech, Daniel J.; Croft, Steve; DeBoer, David; Gajjar, Vishal; Isaacson, Howard; Lacki, Brian C.; Lebofsky, Matt; MacMahon, David H. E.; Ng, Cherry; Perez, Karen I.; Siemion, Andrew P. V.; Webb, Claire Isabel; Drew, Jamie; Worden, S. Pete; Zic, Andrew Bibcode: 2021NatAs...5.1148S Altcode: 2021NatAs.tmp..203S; 2021arXiv211108007S The detection of life beyond Earth is an ongoing scientific pursuit, with profound implications. One approach, known as the search for extraterrestrial intelligence (SETI), seeks to find engineered signals (`technosignatures') that indicate the existence of technologically capable life beyond Earth. Here, we report on the detection of a narrowband signal of interest at ~982 MHz, recorded during observations towards Proxima Centauri with the Parkes Murriyang radio telescope. This signal, BLC1, has characteristics broadly consistent with hypothesized technosignatures and is one of the most compelling candidates to date. Analysis of BLC1—which we ultimately attribute to being an unusual but locally generated form of interference—is provided in a companion paper. Nevertheless, our observations of Proxima Centauri are a particularly sensitive search for radio technosignatures towards a stellar target. Title: Analysis of the Breakthrough Listen signal of interest blc1 with a technosignature verification framework Authors: Sheikh, Sofia Z.; Smith, Shane; Price, Danny C.; DeBoer, David; Lacki, Brian C.; Czech, Daniel J.; Croft, Steve; Gajjar, Vishal; Isaacson, Howard; Lebofsky, Matt; MacMahon, David H. E.; Ng, Cherry; Perez, Karen I.; Siemion, Andrew P. V.; Webb, Claire Isabel; Zic, Andrew; Drew, Jamie; Worden, S. Pete Bibcode: 2021NatAs...5.1153S Altcode: 2021arXiv211106350S; 2021NatAs.tmp..206S The aim of the search for extraterrestrial intelligence (SETI) is to find technologically capable life beyond Earth through their technosignatures. On 2019 April 29, the Breakthrough Listen SETI project observed Proxima Centauri with the Parkes `Murriyang' radio telescope. These data contained a narrowband signal with characteristics broadly consistent with a technosignature near 982 MHz (`blc1'). Here we present a procedure for the analysis of potential technosignatures, in the context of the ubiquity of human-generated radio interference, which we apply to blc1. Using this procedure, we find that blc1 is not an extraterrestrial technosignature, but rather an electronically drifting intermodulation product of local, time-varying interferers aligned with the observing cadence. We find dozens of instances of radio interference with similar morphologies to blc1 at frequencies harmonically related to common clock oscillators. These complex intermodulation products highlight the necessity for detailed follow-up of any signal of interest using a procedure such as the one outlined in this work. Title: The Breakthrough Listen Search for Intelligent Life: Searching for Technosignatures in Observations of TESS Targets of Interest Authors: Traas, Raffy; Croft, Steve; Gajjar, Vishal; Isaacson, Howard; Lebofsky, Matt; MacMahon, David H. E.; Perez, Karen; Price, Danny C.; Sheikh, Sofia; Siemion, Andrew P. V.; Smith, Shane; Drew, Jamie; Worden, S. Pete Bibcode: 2021AJ....161..286T Altcode: 2021arXiv210111137T Exoplanetary systems are prime targets for the Search for Extraterrestrial Intelligence (SETI). With the recent uptick in the identification of candidate and confirmed exoplanets through the work of missions like the Transiting Exoplanet Survey Satellite (TESS), we are beginning to understand that Earth-like planets are common. In this work, we extend the Breakthrough Listen (BL) search for extraterrestrial intelligence to include targeted searches of stars identified by TESS as potential exoplanet hosts. We report on $113$ 30 minute cadence observations collected for 28 targets selected from the TESS Input Catalog from among those identified as containing signatures of transiting planets. The targets were searched for narrowband signals from 1 to 11 GHz using the turboSETI pipeline architecture modified for compatibility with the Google Cloud environment. Data were searched for drift rates of ±4 Hz s-1 above a minimum signal-to-noise threshold of 10, following the parameters of previous searches conducted by Price et al. and Enriquez et al. The observations presented in this work establish some of the deepest limits to date over such a wide band (1-11 GHz) for life beyond Earth. We determine that fewer than 12.72% of the observed targets possess transmitters operating at these frequencies with an equivalent isotropic radiated power greater than our derived threshold of $4.9\times {10}^{14}\,{\rm{W}}$ . Title: Expanded Capability of the Breakthrough Listen Parkes Data Recorder for Observations with the UWL Receiver Authors: Price, Danny C.; MacMahon, David H. E.; Lebofsky, Matt; Isaacson, Howard; Sheikh, Sofia; Czech, Daniel; Gajjar, Vishal; Siemion, Andrew; Drew, Jamie; Worden, S. Pete; Green, James A.; Craig, Daniel; Amy, Shaun Bibcode: 2021RNAAS...5..114P Altcode: The ultra-wideband low (UWL) receiver is a new feed for the Parkes telescope, which covers the combined bandwidth of four previously installed receivers. In order to use the UWL for technosignature observations, several updates and upgrades were made on the Breakthrough Listen Parkes Data Recorder (BLPDR). This Research Note summarizes BLPDR hardware upgrades and new capacity for technosignature observations with the UWL receiver. Title: Lunar Opportunities for SETI Authors: Michaud, Eric; Siemion, Andrew P. V.; Drew, Jamie; Worden, S. Pete Bibcode: 2021BAAS...53d.369M Altcode: 2021psad.rept..369M A radio telescope placed in lunar orbit, or on the surface of the Moon's farside, could be of great value to the Search for Extraterrestrial Intelligence (SETI). In this paper, we review existing literature on Moon-based radio astronomy, discuss the benefits of lunar SETI, and contrast possible mission concepts. Title: Re-analysis of Breakthrough Listen Observations of FRB 121102: Polarization Properties of Eight New Spectrally Narrow Bursts Authors: Faber, Jakob T.; Gajjar, Vishal; Siemion, Andrew P. V.; Croft, Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Drew, Jamie; Isaacson, Howard; Lacki, Brian C.; Lebofsky, Matt; MacMahon, David H. E.; Ng, Cherry; Pater, Imke de; Price, Danny C.; Sheikh, Sofia Z.; Webb, Claire; Worden, S. Pete Bibcode: 2021RNAAS...5...17F Altcode: 2021arXiv210105172F We report polarization properties for eight narrowband bursts from FRB 121102 that have been re-detected in a high-frequency (4-8 GHz) Breakthrough Listen observation with the Green Bank Telescope, originally taken on 2017 August 26. The bursts were found to exhibit nearly 100% linear polarization, Faraday rotation measures bordering 9.3 × 104 rad m-2, and stable polarization position angles, all of which agree with burst properties previously reported for FRB 121102 at the same epoch. We confirm that these detections are indeed physical bursts with limited spectral occupancies and further support the use of sub-banded search techniques in FRB detection. Title: Narrow-band Signal Localization for SETI on Noisy Synthetic Spectrogram Data Authors: Brzycki, Bryan; Siemion, Andrew P. V.; Croft, Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Drew, Jamie; Gajjar, Vishal; Isaacson, Howard; Lacki, Brian; Lebofsky, Matthew; MacMahon, David H. E.; de Pater, Imke; Price, Danny C.; Worden, S. Pete Bibcode: 2020PASP..132k4501B Altcode: 2020arXiv200604362B As it stands today, the search for extraterrestrial intelligence is highly dependent on our ability to detect interesting candidate signals, or technosignatures, in radio telescope observations and distinguish these from human radio frequency interference (RFI). Current signal search pipelines look for signals in spectrograms of intensity as a function of time and frequency (which can be thought of as images), but tend to do poorly in identifying multiple signals in a single data frame. This is especially apparent when there are dim signals in the same frame as bright, high signal-to-noise ratio (S/N) signals. In this work, we approach this problem using convolutional neural networks (CNN) as a computationally efficient method for localizing signals in synthetic observations resembling data collected by Breakthrough Listen using the Green Bank Telescope. We generate two synthetic data sets, the first with exactly one signal at various S/N levels and the second with exactly two signals, one of which represents RFI. We find that a residual CNN with strided convolutions and using multiple image normalizations as input outperforms a more basic CNN with max pooling trained on inputs with only one normalization. Training each model on a smaller subset of the training data at higher S/N levels results in a significant increase in model performance, reducing root mean square errors by at least a factor of 3 at an S/N of 25 dB. Although each model produces outliers with significant error, these results demonstrate that using CNNs to analyze signal location is promising, especially in image frames that are crowded with multiple signals. Title: Lunar Opportunities for SETI Authors: Michaud, Eric J.; Siemion, Andrew P. V.; Drew, Jamie; Worden, S. Pete Bibcode: 2020arXiv200912689M Altcode: A radio telescope placed in lunar orbit, or on the surface of the Moon's farside, could be of great value to the Search for Extraterrestrial Intelligence (SETI). The advantage of such a telescope is that it would be shielded by the body of the Moon from terrestrial sources of radio frequency interference (RFI). While RFI can be identified and ignored by other fields of radio astronomy, the possible spectral similarity between human and alien-generated radio emission makes the abundance of artificial radio emission on and around the Earth a significant complicating factor for SETI. A Moon-based telescope would avoid this challenge. In this paper, we review existing literature on Moon-based radio astronomy, discuss the benefits of lunar SETI, contrast possible surface- and orbit-based telescope designs, and argue that such initiatives are scientifically feasible, both technically and financially, within the next decade. Title: Breakthrough Listen Search for Technosignatures toward the Kepler-160 System Authors: Perez, Karen; Brzycki, Bryan; Gajjar, Vishal; Isaacson, Howard; Siemion, Andrew; Croft, Steve; DeBoer, David; Lebofsky, Matt; MacMahon, David H. E.; Price, Danny C.; Sheikh, Sofia; Drew, Jamie; Worden, S. Pete Bibcode: 2020RNAAS...4...97P Altcode: 2020arXiv200613789P We have conducted a search for artificial radio emission associated with the Kepler-160 system following the report of the discovery of the Earth-like planet candidate KOI-456.04 on 2020 June 4 (Heller et al. 2020). Our search targeted both narrowband (2.97 Hz) drifting (±4 Hz s-1) and wideband pulsed (5 ms at all bandwidths) artificially dispersed technosignatures using the turboSETI (Enriquez et al. 2017) and SPANDAK (V. Gajjar et al. 2020, in preparation) pipelines, respectively, from 1 to 8 GHz. No candidates were identified above an upper limit Equivalent Isotropic Radiated Power of 5.9 × 1014 W for narrowband emission and 7.3 × 1012 W for wideband emission. Here we briefly describe our observations and data reduction procedure. Title: Exploration of the outer solar system with fast and small sailcraft Authors: Turyshev, Slava G.; Klupar, Peter; Loeb, Abraham; Manchester, Zachary; Parkin, Kevin; Witten, Edward; Worden, S. Pete Bibcode: 2020arXiv200512336T Altcode: Two new interplanetary technologies have advanced in the past decade to the point where they may enable exciting, affordable missions that reach further and faster deep into the outer regions of our solar system: (i) small and capable interplanetary spacecraft and (ii) light-driven sails. Combination of these two technologies could drastically reduce travel times within the solar system. We discuss a new paradigm that involves small and fast moving sailcraft that could enable exploration of distant regions of the solar system much sooner and faster than previously considered. We present some of the exciting science objectives for these miniaturized intelligent space systems that could lead to transformational advancements in the space sciences in the coming decade. Title: Opportunities to search for extraterrestrial intelligence with the FAST Authors: Li, Di; Gajjar, Vishal; Wang, Pei; Siemion, Andrew; Zhang, Zhi-Song; Zhang, Hai-Yan; Yue, You-Ling; Zhu, Yan; Jin, Cheng-Jin; Li, Shi-Yu; Berger, Sabrina; Brzycki, Bryan; Cobb, Jeff; Croft, Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Drew, Jamie; Emilio Enriquez, J.; Gizani, Nectaria; Korpela, Eric J.; Isaacson, Howard; Lebofsky, Matthew; Lacki, Brian; MacMahon, David H. E.; Nanez, Morgan; Niu, Chen-Hui; Pei, Xin; Price, Danny C.; Werthimer, Dan; Worden, Pete; Gerry Zhang, Yunfan; Zhang, Tong-Jie; FAST Collaboration Bibcode: 2020RAA....20...78L Altcode: The discovery of ubiquitous habitable extrasolar planets, combined with revolutionary advances in instrumentation and observational capabilities, has ushered in a renaissance in the search for extraterrestrial intelligence (SETI). Large scale SETI activities are now underway at numerous international facilities. The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is the largest single-aperture radio telescope in the world, and is well positioned to conduct sensitive searches for radio emission indicative of exo-intelligence. SETI is one of the five key science goals specified in the original FAST project plan. A collaboration with the Breakthrough Listen Initiative was initiated in 2016 with a joint statement signed both by Dr. Jun Yan, the then director of National Astronomical Observatories, Chinese Academy of Sciences (NAOC), and Dr. Peter Worden, Chairman of the Breakthrough Prize Foundation. In this paper, we highlight some of the unique features of FAST that will allow for novel SETI observations. We identify and describe three different signal types indicative of a technological source, namely, narrow band, wide-band artificially dispersed and modulated signals. Here, we propose observations with FAST to achieve sensitivities never before explored. For nearby exoplanets, such as TESS targets, FAST will be sensitive to an EIRP of 1.9 × 1011 W, well within the reach of current human technology. For the Andromeda Galaxy, FAST will be able to detect any Kardashev type II or more advanced civilization there. Title: The Breakthrough Listen Search for Intelligent Life: Observations of 1327 Nearby Stars Over 1.10-3.45 GHz Authors: Price, Danny C.; Enriquez, J. Emilio; Brzycki, Bryan; Croft, Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Foster, Griffin; Gajjar, Vishal; Gizani, Nectaria; Hellbourg, Greg; Isaacson, Howard; Lacki, Brian; Lebofsky, Matt; MacMahon, David H. E.; Pater, Imke de; Siemion, Andrew P. V.; Werthimer, Dan; Green, James A.; Kaczmarek, Jane F.; Maddalena, Ronald J.; Mader, Stacy; Drew, Jamie; Worden, S. Pete Bibcode: 2020AJ....159...86P Altcode: 2019arXiv190607750P Breakthrough Listen (BL) is a 10 year initiative to search for signatures of technologically capable life beyond Earth via radio and optical observations of the local universe. A core part of the BL program is a comprehensive survey of 1702 nearby stars at radio wavelengths (1-10 GHz). Here, we report on observations with the 64 m CSIRO Parkes radio telescope in New South Wales, Australia, and the 100 m Robert C. Byrd Green Bank radio telescope in West Virginia, USA. Over 2016 January to 2019 March, a sample of 1138 stars was observed at Green Bank using the 1.10-1.90 GHz and 1.80-2.80 GHz receivers, and 189 stars were observed with Parkes over 2.60-3.45 GHz. We searched these data for the presence of engineered signals with Doppler-acceleration drift rates between ±4 Hz s-1. Here, we detail our data analysis techniques and provide examples of detected events. After excluding events with characteristics consistent with terrestrial radio interference, we are left with zero candidates. That is, we find no evidence of putative radio transmitters above $2.1\times {10}^{12}$ W, and $9.1\times {10}^{12}$ W for Green Bank and Parkes observations, respectively. These observations constitute the most comprehensive search over 1.10-3.45 GHz for technosignatures to date. All data products, totaling ∼219 TB, are available for download as part of the first BL data release (DR1), as described in a companion paper. Title: Opportunities to Search for Extra-Terrestrial Intelligence with the Five-hundred-meter Aperture Spherical radio Telescope Authors: Li, Di; Gajjar, Vishal; Wang, Pei; Siemion, Andrew; Zhang, Zhisong; Zhang, Haiyan; Yue, Youling; Zhu, Yan; Jin, Chengjin; Li, Shiyu; Berger, Sabrina; Brzycki, Bryan; Cobb, Jeff; Croft, Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Drew, Jamie; Enriquez, J. Emilio; Gizani, Nectaria; Korpela, Eric J.; Isaacson, Howard; Lebofsky, Matthew; Lacki, Brian; MacMahon, David H. E.; Nanez, Morgan; Niu, Chenhui; Pei, Xin; Price, Danny C.; Werthimer, Dan; Worden, Pete; Zhang, Yunfan Gerry; Zhang, Tong-Jie; FAST Collaboration Bibcode: 2020arXiv200309639L Altcode: The discovery of ubiquitous habitable extrasolar planets, combined with revolutionary advances in instrumentation and observational capabilities, has ushered in a renaissance in the search for extra-terrestrial intelligence (SETI). Large scale SETI activities are now underway at numerous international facilities. The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is the largest single-aperture radio telescope in the world, well positioned to conduct sensitive searches for radio emission indicative of exo-intelligence. SETI is one of the five key science goals specified in the original FAST project plan. A collaboration with the Breakthrough Listen Initiative has been initiated in 2016 with a joint statement signed both by Dr. Jun Yan, the then director of the National Astronomical Observatories, Chinese Academy of Sciences (NAOC), and Dr. Peter Worden, the Chairman of the Breakthrough Prize Foundation. In this paper, we highlight some of the unique features of FAST that will allow for novel SETI observations. We identify and describe three different signal types indicative of a technological source, namely, narrow-band, wide-band artificially dispersed, and modulated signals. We here propose observations with FAST to achieve sensitivities never before explored. Title: The Breakthrough Listen Search for Intelligent Life: Public Data, Formats, Reduction, and Archiving Authors: Lebofsky, Matthew; Croft, Steve; Siemion, Andrew P. V.; Price, Danny C.; Enriquez, J. Emilio; Isaacson, Howard; MacMahon, David H. E.; Anderson, David; Brzycki, Bryan; Cobb, Jeff; Czech, Daniel; DeBoer, David; DeMarines, Julia; Drew, Jamie; Foster, Griffin; Gajjar, Vishal; Gizani, Nectaria; Hellbourg, Greg; Korpela, Eric J.; Lacki, Brian; Sheikh, Sofia; Werthimer, Dan; Worden, Pete; Yu, Alex; Zhang, Yunfan Gerry Bibcode: 2019PASP..131l4505L Altcode: 2019arXiv190607391L Breakthrough Listen is the most comprehensive and sensitive search for extraterrestrial intelligence (SETI) to date, employing a collection of international observational facilities including both radio and optical telescopes. During the first three years of the Listen program, thousands of targets have been observed with the Green Bank Telescope (GBT), Parkes Telescope and Automated Planet Finder. At GBT and Parkes, observations have been performed ranging from 700 MHz to 26 GHz, with raw data volumes averaging over 1 PB day-1. A pseudo-real time software spectroscopy suite is used to produce multi-resolution spectrograms amounting to approximately 400 GB h-1 GHz-1 beam-1. For certain targets, raw baseband voltage data is also preserved. Observations with the Automated Planet Finder produce both two-dimensional and one-dimensional high-resolution (R ∼ 105) echelle spectral data. Although the primary purpose of Listen data acquisition is for SETI, a range of secondary science has also been performed with these data, including studies of fast radio bursts. Other current and potential research topics include spectral line studies, searches for certain kinds of dark matter, probes of interstellar scattering, pulsar searches, radio transient searches and investigations of stellar activity. Listen data are also being used in the development of algorithms, including machine-learning approaches to modulation scheme classification and outlier detection, that have wide applicability not just for astronomical research but for a broad range of science and engineering. In this paper, we describe the hardware and software pipeline used for collection, reduction, archival, and public dissemination of Listen data. We describe the data formats and tools, and present Breakthrough Listen Data Release 1.0 (BLDR 1.0), a defined set of publicly available raw and reduced data totaling 1 PB. Title: Breakthrough Listen Follow-up of the Random Transiter (EPIC 249706694/HD 139139) with the Green Bank Telescope Authors: Brzycki, Bryan; Siemion, Andrew; Croft, Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Drew, Jamie; Enriquez, J. Emilio; Gajjar, Vishal; Gizani, Nectaria; Isaacson, Howard; Lacki, Brian; Lebofsky, Matt; MacMahon, David H. E.; de Pater, Imke; Price, Danny C.; Sheikh, Sofia; Webb, Claire; Worden, S. Pete Bibcode: 2019RNAAS...3..147B Altcode: 2019arXiv191003711B The star EPIC 249706694 (HD 139139) was found to exhibit 28 transit-like events over an 87 day period during the Kepler mission's K2 Campaign 15 (Rappaport et al. 2019). These events did not fall into an identifiable pattern and could not be explained by a multitude of transit scenarios explored by the authors. We conduct follow-up observations at C-band frequencies with the Green Bank Telescope as part of the ongoing Breakthrough Listen search for technosignatures. We search for narrow band signals above a signal-to-noise threshold of 10 and with Doppler drift rates within +-5 Hz/s. We detect no evidence of technosignatures from EPIC 249706694 and derive an upper limit for the EIRP (Equivalent Isotropic Radiated Power) of putative transmissions to be 10 TW. Title: The Breakthrough Listen Search for Extraterrestrial Intelligence Authors: Gajjar, Vishal; Siemion, Andrew; Croft, Steve; Brzycki, Bryan; Burgay, Marta; Carozzi, Tobia; Concu, Raimondo; Czech, Daniel; DeBoer, David; DeMarines, Julia; Drew, Jamie; Enriquez, J. Emilio; Fawcett, James; Gallagher, Peter; Gerret, Michael; Gizani, Nectaria; Hellbourg, Greg; Holder, Jamie; Isaacson, Howard; Kudale, Sanjay; Lacki, Brian; Lebofsky, Matthew; Li, Di; MacMahon, David H. E.; McCauley, Joe; Melis, Andrea; Molinari, Emilio; Murphy, Pearse; Perrodin, Delphine; Pilia, Maura; Price, Danny C.; Webb, Claire; Werthimer, Dan; Williams, David; Worden, Pete; Zarka, Philippe; Zhang, Yunfan Gerry Bibcode: 2019BAAS...51g.223G Altcode: 2019astro2020U.223G; 2019arXiv190705519G In this white paper, we outline the status of the on-going observing campaign with our primary and collaborative observing facilities, as well as planned activities with these instruments over the next few years with the Breakthrough Listen program for the technosignature searches. Title: A fast radio burst with frequency-dependent polarization detected during Breakthrough Listen observations Authors: Price, D. C.; Foster, G.; Geyer, M.; van Straten, W.; Gajjar, V.; Hellbourg, G.; Karastergiou, A.; Keane, E. F.; Siemion, A. P. V.; Arcavi, I.; Bhat, R.; Caleb, M.; Chang, S. -W.; Croft, S.; DeBoer, D.; de Pater, I.; Drew, J.; Enriquez, J. E.; Farah, W.; Gizani, N.; Green, J. A.; Isaacson, H.; Hickish, J.; Jameson, A.; Lebofsky, M.; MacMahon, D. H. E.; Möller, A.; Onken, C. A.; Petroff, E.; Werthimer, D.; Wolf, C.; Worden, S. P.; Zhang, Y. G. Bibcode: 2019MNRAS.486.3636P Altcode: 2019MNRAS.tmp..950P; 2019arXiv190107412P Here, we report on the detection and verification of fast radio burst FRB 180301, which occurred on UTC 2018 March 1 during the Breakthrough Listen observations with the Parkes telescope. Full-polarization voltage data of the detection were captured - a first for non-repeating FRBs - allowing for coherent de-dispersion and additional verification tests. The coherently de-dispersed dynamic spectrum of FRB 180301 shows complex, polarized frequency structure over a small fractional bandwidth. As FRB 180301 was detected close to the geosynchronous satellite band during a time of known 1-2 GHz satellite transmissions, we consider whether the burst was due to radio interference emitted or reflected from an orbiting object. Based on the pre-ponderance of our verification tests, we cannot conclusively determine FRB 180301 to be either astrophysical or anthropogenic in origin. Title: Breakthrough Listen Observations of Asteroid (514107) 2015 BZ509 with the Parkes Radio Telescope Authors: Price, Danny C.; Croft, Steve; DeBoer, David; Drew, Jamie; Enriquez, J. Emilio; Foster, Griffin; Gajjar, Vishal; Gizani, Nectaria; Hellbourg, Greg; Isaacson, Howard; Lebofsky, Matt; MacMahon, David H. E.; de Pater, Imke; Siemion, Andrew; Worden, S. Pete; Zhang, Yufan Gerry Bibcode: 2019RNAAS...3...19P Altcode: 2019RNAAS...3a..19P No abstract at ADS Title: Philanthropic Space Science: The Breakthrough Initiatives Authors: Worden, Simon P.; Drew, Jamie; Klupar, Peter Bibcode: 2018NewSp...6..262W Altcode: No abstract at ADS Title: mSTAR: Testing Lorentz invariance in a low Earth orbit with high performance optical frequency standards Authors: Saraf, Shailendhar; Buchman, Sasha; Cutler, Grant D.; Lipa, John; Tan, Si; Byer, Robert; Schuldt, Thilo; Dittus, HansjöRg Braxmaier, Claus; Peters, Achim; DöRingshoff, Klaus; Hanson, John; Jaroux, Belgacem; Worden, Simon P.; Alfauwaz, Abdul; Alhussien, Abdulaziz; Alsuwaidan, Badr; Saud, Turki Al; Gürlebeck, Norman; Herrmann, Sven; LäMmerzahl, Claus; Johann, Ulrich Bibcode: 2018mgm..conf.3591S Altcode: The mini Space Time Asymmetry Research (mSTAR) is a proposed space mission to perform an advanced Kennedy-Thorndike (KT) test of Special Relativity using the large and rapid velocity modulation available in low Earth orbit (LEO). The mission goal is to test special relativity by performing a clock-clock comparison experiment in LEO, thereby testing the boost dependence of the speed of light. Clocks with stabilities better than 10-15 level at orbit time will allow the KT coefficient to be measured with up to two orders of magnitude higher accuracy than current ground-based experiments, with an additional factor of 10 possible using more advanced technology. In the current baseline, mSTAR utilizes an absolute frequency reference based on modulation transfer spectroscopy of molecular iodine and a length-reference based on a high-finesse ultra-stable optical cavity. Current efforts aim at a space compatible design of the two clocks and improving the long-term stability of the cavity reference. In a recently completed Phase A study, the feasibility of accommodating the mSTAR experiment on a SaudiSat 4 bus was investigated. Title: Breakthrough Listen - A New Search for Life in the Universe Authors: Worden, Pete Bibcode: 2016iac..conf34378W Altcode: On July 20, 2015 Yuri Milner and Stephen Hawking announced a new set of scientific initiatives - a SETI search called Breakthrough Listen and a contest to devise potential messages in response to a detection entitled Breakthrough Message. These are the first of several privately-funded Breakthrough Initiatives, designed to answer the fundamental science questions surrounding the origin, extent and nature of life in the universe. The initiatives are managed by the Breakthrough Prize Foundation. With Breakthrough Listen, Radio SETI observations have begun at the Green Bank Radio Telescope (GBT) and optical SETI at the Lick Observatory Automated Planet Finder (APF). Observations will soon commence at the CSIRO Parkes Radio Telescope. Other SETI instruments and observations are under consideration. In addition, several other initiatives are under development including an expanded search for life in the universe. Title: Gravity Probe B data analysis: II. Science data and their handling prior to the final analysis Authors: Silbergleit, A. S.; Conklin, J. W.; Heifetz, M. I.; Holmes, T.; Li, J.; Mandel, I.; Solomonik, V. G.; Stahl, K.; Worden, P. W., Jr.; Everitt, C. W. F.; Adams, M.; Berberian, J. E.; Bencze, W.; Clarke, B.; Al-Jadaan, A.; Keiser, G. M.; Kozaczuk, J. A.; Al-Meshari, M.; Muhlfelder, B.; Salomon, M.; Santiago, D. I.; Al-Suwaidan, B.; Turneaure, J. P.; Wade, J. Bibcode: 2015CQGra..32v4019S Altcode: The results of the Gravity Probe B relativity science mission published in Everitt et al (2011 Phys. Rev. Lett. 106 221101) required a rather sophisticated analysis of experimental data due to several unexpected complications discovered on-orbit. We give a detailed description of the Gravity Probe B data reduction. In the first paper (Silbergleit et al Class. Quantum Grav. 22 224018) we derived the measurement models, i.e., mathematical expressions for all the signals to analyze. In the third paper (Conklin et al Class. Quantum Grav. 22 224020) we explain the estimation algorithms and their program implementation, and discuss the experiment results obtained through data reduction. This paper deals with the science data preparation for the main analysis yielding the relativistic drift estimates. Title: Gravity Probe B data analysis: I. Coordinate frames and analysis models Authors: Silbergleit, A. S.; Keiser, G. M.; Turneaure, J. P.; Conklin, J. W.; Everitt, C. W. F.; Heifetz, M. I.; Holmes, T.; Worden, P. W., Jr. Bibcode: 2015CQGra..32v4018S Altcode: Gravity Probe B (GP-B) was a cryogenic, space-based experiment testing the geodetic and frame-dragging predictions of Einstein's theory of general relativity (GR) by means of gyroscopes in Earth orbit. This first of three data analysis papers reviews the GR predictions and details the models that provide the framework for the relativity analysis. In the second paper we describe the flight data and their preprocessing. The third paper covers the algorithms and software tools that fit the preprocessed flight data to the models to give the experimental results published in Everitt et al (2011 Phys. Rev. Lett. 106 221101-4). Title: The Gravity Probe B test of general relativity Authors: Everitt, C. W. F.; Muhlfelder, B.; DeBra, D. B.; Parkinson, B. W.; Turneaure, J. P.; Silbergleit, A. S.; Acworth, E. B.; Adams, M.; Adler, R.; Bencze, W. J.; Berberian, J. E.; Bernier, R. J.; Bower, K. A.; Brumley, R. W.; Buchman, S.; Burns, K.; Clarke, B.; Conklin, J. W.; Eglington, M. L.; Green, G.; Gutt, G.; Gwo, D. H.; Hanuschak, G.; He, X.; Heifetz, M. I.; Hipkins, D. N.; Holmes, T. J.; Kahn, R. A.; Keiser, G. M.; Kozaczuk, J. A.; Langenstein, T.; Li, J.; Lipa, J. A.; Lockhart, J. M.; Luo, M.; Mandel, I.; Marcelja, F.; Mester, J. C.; Ndili, A.; Ohshima, Y.; Overduin, J.; Salomon, M.; Santiago, D. I.; Shestople, P.; Solomonik, V. G.; Stahl, K.; Taber, M.; Van Patten, R. A.; Wang, S.; Wade, J. R.; Worden, P. W., Jr.; Bartel, N.; Herman, L.; Lebach, D. E.; Ratner, M.; Ransom, R. R.; Shapiro, I. I.; Small, H.; Stroozas, B.; Geveden, R.; Goebel, J. H.; Horack, J.; Kolodziejczak, J.; Lyons, A. J.; Olivier, J.; Peters, P.; Smith, M.; Till, W.; Wooten, L.; Reeve, W.; Anderson, M.; Bennett, N. R.; Burns, K.; Dougherty, H.; Dulgov, P.; Frank, D.; Huff, L. W.; Katz, R.; Kirschenbaum, J.; Mason, G.; Murray, D.; Parmley, R.; Ratner, M. I.; Reynolds, G.; Rittmuller, P.; Schweiger, P. F.; Shehata, S.; Triebes, K.; VandenBeukel, J.; Vassar, R.; Al-Saud, T.; Al-Jadaan, A.; Al-Jibreen, H.; Al-Meshari, M.; Al-Suwaidan, B. Bibcode: 2015CQGra..32v4001E Altcode: The Gravity Probe B mission provided two new quantitative tests of Einstein's theory of gravity, general relativity (GR), by cryogenic gyroscopes in Earth's orbit. Data from four gyroscopes gave a geodetic drift-rate of -6601.8 ± 18.3 marc-s yr-1 and a frame-dragging of -37.2 ± 7.2 marc-s yr-1, to be compared with GR predictions of -6606.1 and -39.2 marc-s yr-1 (1 marc-s = 4.848 × 10-9 radians). The present paper introduces the science, engineering, data analysis, and heritage of Gravity Probe B, detailed in the accompanying 20 CQG papers. Title: Erratum: “Science With a Wide-Field UV Transient Explorer” (2014, AJ, 147, 79) Authors: Sagiv, I.; Gal-Yam, A.; Ofek, E. O.; Waxman, E.; Aharonson, O.; Kulkarni, S. R.; Nakar, E.; Maoz, D.; Trakhtenbrot, B.; Gottesman, O.; Phinney, E. S.; Topaz, J.; Beichman, C.; Murthy, J.; Worden, S. P. Bibcode: 2014AJ....148..138S Altcode: No abstract at ADS Title: The Interface Region Imaging Spectrograph (IRIS) Authors: De Pontieu, B.; Title, A. M.; Lemen, J. R.; Kushner, G. D.; Akin, D. J.; Allard, B.; Berger, T.; Boerner, P.; Cheung, M.; Chou, C.; Drake, J. F.; Duncan, D. W.; Freeland, S.; Heyman, G. F.; Hoffman, C.; Hurlburt, N. E.; Lindgren, R. W.; Mathur, D.; Rehse, R.; Sabolish, D.; Seguin, R.; Schrijver, C. J.; Tarbell, T. D.; Wülser, J. -P.; Wolfson, C. J.; Yanari, C.; Mudge, J.; Nguyen-Phuc, N.; Timmons, R.; van Bezooijen, R.; Weingrod, I.; Brookner, R.; Butcher, G.; Dougherty, B.; Eder, J.; Knagenhjelm, V.; Larsen, S.; Mansir, D.; Phan, L.; Boyle, P.; Cheimets, P. N.; DeLuca, E. E.; Golub, L.; Gates, R.; Hertz, E.; McKillop, S.; Park, S.; Perry, T.; Podgorski, W. A.; Reeves, K.; Saar, S.; Testa, P.; Tian, H.; Weber, M.; Dunn, C.; Eccles, S.; Jaeggli, S. A.; Kankelborg, C. C.; Mashburn, K.; Pust, N.; Springer, L.; Carvalho, R.; Kleint, L.; Marmie, J.; Mazmanian, E.; Pereira, T. M. D.; Sawyer, S.; Strong, J.; Worden, S. P.; Carlsson, M.; Hansteen, V. H.; Leenaarts, J.; Wiesmann, M.; Aloise, J.; Chu, K. -C.; Bush, R. I.; Scherrer, P. H.; Brekke, P.; Martinez-Sykora, J.; Lites, B. W.; McIntosh, S. W.; Uitenbroek, H.; Okamoto, T. J.; Gummin, M. A.; Auker, G.; Jerram, P.; Pool, P.; Waltham, N. Bibcode: 2014SoPh..289.2733D Altcode: 2014arXiv1401.2491D; 2014SoPh..tmp...25D The Interface Region Imaging Spectrograph (IRIS) small explorer spacecraft provides simultaneous spectra and images of the photosphere, chromosphere, transition region, and corona with 0.33 - 0.4 arcsec spatial resolution, two-second temporal resolution, and 1 km s−1 velocity resolution over a field-of-view of up to 175 arcsec × 175 arcsec. IRIS was launched into a Sun-synchronous orbit on 27 June 2013 using a Pegasus-XL rocket and consists of a 19-cm UV telescope that feeds a slit-based dual-bandpass imaging spectrograph. IRIS obtains spectra in passbands from 1332 - 1358 Å, 1389 - 1407 Å, and 2783 - 2834 Å, including bright spectral lines formed in the chromosphere (Mg II h 2803 Å and Mg II k 2796 Å) and transition region (C II 1334/1335 Å and Si IV 1394/1403 Å). Slit-jaw images in four different passbands (C II 1330, Si IV 1400, Mg II k 2796, and Mg II wing 2830 Å) can be taken simultaneously with spectral rasters that sample regions up to 130 arcsec × 175 arcsec at a variety of spatial samplings (from 0.33 arcsec and up). IRIS is sensitive to emission from plasma at temperatures between 5000 K and 10 MK and will advance our understanding of the flow of mass and energy through an interface region, formed by the chromosphere and transition region, between the photosphere and corona. This highly structured and dynamic region not only acts as the conduit of all mass and energy feeding into the corona and solar wind, it also requires an order of magnitude more energy to heat than the corona and solar wind combined. The IRIS investigation includes a strong numerical modeling component based on advanced radiative-MHD codes to facilitate interpretation of observations of this complex region. Approximately eight Gbytes of data (after compression) are acquired by IRIS each day and made available for unrestricted use within a few days of the observation. Title: Science with a Wide-field UV Transient Explorer Authors: Sagiv, I.; Gal-Yam, A.; Ofek, E. O.; Waxman, E.; Aharonson, O.; Kulkarni, S. R.; Nakar, E.; Maoz, D.; Trakhtenbrot, B.; Phinney, E. S.; Topaz, J.; Beichman, C.; Murthy, J.; Worden, S. P. Bibcode: 2014AJ....147...79S Altcode: 2013arXiv1303.6194S The time-variable electromagnetic sky has been well-explored at a wide range of wavelengths. In contrast, the ultra-violet (UV) variable sky is relatively poorly explored, even though it offers exciting scientific prospects. Here, we review the potential scientific impact of a wide-field UV survey on the study of explosive and other transient events, as well as known classes of variable objects, such as active galactic nuclei and variable stars. We quantify our predictions using a fiducial set of observational parameters which are similar to those envisaged for the proposed ULTRASAT mission. We show that such a mission would be able to revolutionize our knowledge about massive star explosions by measuring the early UV emission from hundreds of events, revealing key physical parameters of the exploding progenitor stars. Such a mission would also detect the UV emission from many tens of tidal-disruption events of stars by supermassive black holes at galactic nuclei and enable a measurement of the rate of such events. The overlap of such a wide-field UV mission with existing and planned gravitational-wave and high-energy neutrino telescopes makes it especially timely. Title: Phobos and Deimos and Mars Environment (PADME): A LADEE-Derived Mission to Explore Mars's Moons and the Martian Orbital Environment Authors: Lee, P.; Bicay, M.; Colaprete, A.; Elphic, R.; Genova, A.; Hine, B.; Horanyi, M.; Jaroux, B.; Korsmeyer, D.; Lewis, B. S.; Worden, S. P. Bibcode: 2014LPI....45.2288L Altcode: PADME is a proposed rapid low-cost NASA Mars orbiter mission that will address longstanding unknowns about Mars’ two moons and the circum-martian environment. Title: Mino's Smile Authors: Worden, Pete Bibcode: 2014SPPhy.150....5W Altcode: No abstract at ADS Title: The Applicability of Emerging Quantum Computing Capabilities to Exo-Planet Research Authors: Correll, Randall; Worden, S. Bibcode: 2014AAS...22320601C Altcode: In conjunction with the Universities Space Research Association and Google, Inc. NASA Ames has acquired a quantum computing device built by DWAVE Systems with approximately 512 “qubits.” Quantum computers have the feature that their capabilities to find solutions to problems with large numbers of variables scale linearly with the number of variables rather than exponentially with that number. These devices may have significant applicability to detection of exoplanet signals in noisy data. We have therefore explored the application of quantum computing to analyse stellar transiting exoplanet data from NASA’s Kepler Mission. The analysis of the case studies was done using the DWAVE Systems’s BlackBox compiler software emulator, although one dataset was run successfully on the DWAVE Systems’s 512 qubit Vesuvius machine. The approach first extracts a list of candidate transits from the photometric lightcurve of a given Kepler target, and then applies a quantum annealing algorithm to find periodicity matches between subsets of the candidate transit list. We examined twelve case studies and were successful in reproducing the results of the Kepler science pipeline in finding validated exoplanets, and matched the results for a pair of candidate exoplanets. We conclude that the current implementation of the algorithm is not sufficiently challenging to require a quantum computer as opposed to a conventional computer. We are developing more robust algorithms better tailored to the quantum computer and do believe that our approach has the potential to extract exoplanet transits in some cases where a conventional approach would not in Kepler data. Additionally, we believe the new quantum capabilities may have even greater relevance for new exoplanet data sets such as that contemplated for NASA’s Transiting Exoplanet Survey Satellite (TESS) and other astrophysics data sets. Title: Solar Cycle Variability and Surface Differential Rotation from Ca II K-line Time Series Data Authors: Scargle, Jeffrey D.; Keil, Stephen L.; Worden, Simon P. Bibcode: 2013ApJ...771...33S Altcode: 2013arXiv1303.6303S Analysis of over 36 yr of time series data from the NSO/AFRL/Sac Peak K-line monitoring program elucidates 5 components of the variation of the 7 measured chromospheric parameters: (a) the solar cycle (period ~ 11 yr), (b) quasi-periodic variations (periods ~ 100 days), (c) a broadband stochastic process (wide range of periods), (d) rotational modulation, and (e) random observational errors, independent of (a)-(d). Correlation and power spectrum analyses elucidate periodic and aperiodic variation of these parameters. Time-frequency analysis illuminates periodic and quasi-periodic signals, details of frequency modulation due to differential rotation, and in particular elucidates the rather complex harmonic structure (a) and (b) at timescales in the range ~0.1-10 yr. These results using only full-disk data suggest that similar analyses will be useful for detecting and characterizing differential rotation in stars from stellar light curves such as those being produced by NASA's Kepler observatory. Component (c) consists of variations over a range of timescales, in the manner of a 1/f random process with a power-law slope index that varies in a systematic way. A time-dependent Wilson-Bappu effect appears to be present in the solar cycle variations (a), but not in the more rapid variations of the stochastic process (c). Component (d) characterizes differential rotation of the active regions. Component (e) is of course not characteristic of solar variability, but the fact that the observational errors are quite small greatly facilitates the analysis of the other components. The data analyzed in this paper can be found at the National Solar Observatory Web site http://nsosp.nso.edu/cak_mon/, or by file transfer protocol at ftp://ftp.nso.edu/idl/cak.parameters. Title: The Interface Region Imaging Spectrograph (IRIS) Authors: De Pontieu, Bart; Title, A. M.; Lemen, J.; Wuelser, J.; Tarbell, T. D.; Schrijver, C. J.; Golub, L.; Kankelborg, C.; Carlsson, M.; Hansteen, V. H.; Worden, S.; IRIS Team Bibcode: 2013SPD....44...03D Altcode: The solar chromosphere and transition region (TR) form a highly structured and dynamic interface region between the photosphere and the corona. This region not only acts as the conduit of all mass and energy feeding into the corona and solar wind, it also requires an order of magnitude more energy to heat than the corona. Nevertheless, the chromosphere remains poorly understood, because of the complexity of the required observational and analytical tools: the interface region is highly complex with transitions from optically thick to optically thin radiation, from pressure to magnetic field domination, and large density and temperature contrasts on small spatial scales. The Interface Region Imaging Spectrograph (IRIS) was selected for a NASA SMEX mission in 2009 and is scheduled to launch on 26-June-2013 (with first light scheduled for mid July). IRIS addresses critical questions: (1) Which types of non-thermal energy dominate in the chromosphere and beyond? (2) How does the chromosphere regulate mass and energy supply to the corona and heliosphere? (3) How do magnetic flux and matter rise through the lower atmosphere, and what role does flux emergence play in flares and mass ejections? These questions are addressed with a high-resolution near and far UV imaging spectrometer sensitive to emission from plasma at temperatures between 5,000 K and 10 MK. IRIS has a field-of-view of 120 arcsec, a spatial resolution of 0.4 arcsec, and velocity resolution of 0.5 km/s. The IRIS investigation includes a strong numerical modeling component based on advanced radiative MHD codes to facilitate interpretation of observations. We describe the IRIS instrumentation and numerical modeling, and present the plans for observations, calibration and data distribution. We will highlight some of the issues that IRIS observations can help resolve. More information can be found at http://iris.lmsal.com Title: LAGRANGE: LAser GRavitational-wave ANtenna in GEodetic Orbit Authors: Buchman, S.; Conklin, J. W.; Balakrishnan, K.; Aguero, V.; Alfauwaz, A.; Aljadaan, A.; Almajed, M.; Altwaijry, H.; Saud, T. A.; Byer, R. L.; Bower, K.; Costello, B.; Cutler, G. D.; DeBra, D. B.; Faied, D. M.; Foster, C.; Genova, A. L.; Hanson, J.; Hooper, K.; Hultgren, E.; Klavins, A.; Lantz, B.; Lipa, J. A.; Palmer, A.; Plante, B.; Sanchez, H. S.; Saraf, S.; Schaechter, D.; Shu, K.; Smith, E.; Tenerelli, D.; Vanbezooijen, R.; Vasudevan, G.; Williams, S. D.; Worden, S. P.; Zhou, J.; Zoellner, A. Bibcode: 2013ASPC..467..191B Altcode: We describe a new space gravitational wave observatory design called LAG-RANGE that maintains all important LISA science at about half the cost and with reduced technical risk. It consists of three drag-free spacecraft in a geocentric formation. Fixed antennas allow continuous contact with the Earth, solving the problem of communications bandwidth and latency. A 70 mm diameter sphere with a 35 mm gap to its enclosure serves as the single inertial reference per spacecraft, operating in “true” drag-free mode (no test mass forcing). Other advantages are: a simple caging design based on the DISCOS 1972 drag-free mission, an all optical read-out with pm fine and nm coarse sensors, and the extensive technology heritage from the Honeywell gyroscopes, and the DISCOS and Gravity Probe B drag-free sensors. An Interferometric Measurement System, designed with reflective optics and a highly stabilized frequency standard, performs the ranging between test masses and requires a single optical bench with one laser per spacecraft. Two 20 cm diameter telescopes per spacecraft, each with infield pointing, incorporate novel technology developed for advanced optical systems by Lockheed Martin, who also designed the spacecraft based on a multi-flight proven bus structure. Additional technological advancements include updated drag-free propulsion, thermal control, charge management systems, and materials. LAGRANGE subsystems are designed to be scalable and modular, making them interchangeable with those of LISA or other gravitational science missions. We plan to space qualify critical technologies on small and nano satellite flights, with the first launch (UV-LED Sat) in 2013. Title: LIMSAT: An Ultra-violet Time Domain Explorer Authors: Phinney, E. S.; Kulkarni, S. R.; Gal-Yam, A.; Ofek, E.; Waxman, E.; Scargle, J.; Worden, S.; Murthy, J. Bibcode: 2013AAS...22135011P Altcode: LIMSAT is a proposed joint US-Israel mini satellite aimed at systematic time domain studies of the UV Universe. The satellite consists of eight 12cm telescopes with a total instantaneous field of view of about 1100 square degrees in the spectral band 200-240nm. A sun-synchronous orbit allows continuous viewing of the anti-sun equatorial region. In one year LIMSAT would have covered an equatorial band (about 2.5% of the sky), providing about one month of continuous photometry of all objects in this field, with all data downlinked within 10 minutes of acquisition. While the primary objective of LIMSAT is the detection of shock breakout, secondary objectives include searches for tidal disruption of stars passing perilously close to nuclear black holes, systematic study of variability of AGN, cataclysmic variables, activity studies of young stars and late type stars, unique studies of extra-solar planets and eclipsing binaries. LIMSAT working along with ground-based synoptic surveys will usher in a new era of time domain studies. Title: Feasibility analysis for a manned mars free-return mission in 2018 Authors: Tito, Dennis A.; Anderson, Grant; Carrico, John P.; Clark, Jonathan; Finger, Barry; Lantz, Gary A.; Loucks, Michel E.; MacCallum, Taber; Poynter, Jane; Squire, Thomas H.; Worden, S. Pete Bibcode: 2013aero.confE.352T Altcode: In 1998 Patel et al searched for Earth-Mars free-return trajectories that leave Earth, fly by Mars, and return to Earth without any deterministic maneuvers after Trans-Mars Injection. They found fast trajectory opportunities occurring two times every 15 years with a 1.4-year duration, significantly less than most Mars free return trajectories, which take up to 3.5 years. This paper investigates these fast trajectories. It also determines the launch and life support feasibility of flying such a mission using hardware expected to be available in time for an optimized fast trajectory opportunity in January, 2018. Title: Radar-Enabled Recovery of the Sutter’s Mill Meteorite, a Carbonaceous Chondrite Regolith Breccia Authors: Jenniskens, Peter; Fries, Marc D.; Yin, Qing-Zhu; Zolensky, Michael; Krot, Alexander N.; Sandford, Scott A.; Sears, Derek; Beauford, Robert; Ebel, Denton S.; Friedrich, Jon M.; Nagashima, Kazuhide; Wimpenny, Josh; Yamakawa, Akane; Nishiizumi, Kunihiko; Hamajima, Yasunori; Caffee, Marc W.; Welten, Kees C.; Laubenstein, Matthias; Davis, Andrew M.; Simon, Steven B.; Heck, Philipp R.; Young, Edward D.; Kohl, Issaku E.; Thiemens, Mark H.; Nunn, Morgan H.; Mikouchi, Takashi; Hagiya, Kenji; Ohsumi, Kazumasa; Cahill, Thomas A.; Lawton, Jonathan A.; Barnes, David; Steele, Andrew; Rochette, Pierre; Verosub, Kenneth L.; Gattacceca, Jérôme; Cooper, George; Glavin, Daniel P.; Burton, Aaron S.; Dworkin, Jason P.; Elsila, Jamie E.; Pizzarello, Sandra; Ogliore, Ryan; Schmitt-Kopplin, Phillipe; Harir, Mourad; Hertkorn, Norbert; Verchovsky, Alexander; Grady, Monica; Nagao, Keisuke; Okazaki, Ryuji; Takechi, Hiroyuki; Hiroi, Takahiro; Smith, Ken; Silber, Elizabeth A.; Brown, Peter G.; Albers, Jim; Klotz, Doug; Hankey, Mike; Matson, Robert; Fries, Jeffrey A.; Walker, Richard J.; Puchtel, Igor; Lee, Cin-Ty A.; Erdman, Monica E.; Eppich, Gary R.; Roeske, Sarah; Gabelica, Zelimir; Lerche, Michael; Nuevo, Michel; Girten, Beverly; Worden, Simon P. Bibcode: 2012Sci...338.1583J Altcode: Doppler weather radar imaging enabled the rapid recovery of the Sutter’s Mill meteorite after a rare 4-kiloton of TNT-equivalent asteroid impact over the foothills of the Sierra Nevada in northern California. The recovered meteorites survived a record high-speed entry of 28.6 kilometers per second from an orbit close to that of Jupiter-family comets (Tisserand’s parameter = 2.8 ± 0.3). Sutter’s Mill is a regolith breccia composed of CM (Mighei)-type carbonaceous chondrite and highly reduced xenolithic materials. It exhibits considerable diversity of mineralogy, petrography, and isotope and organic chemistry, resulting from a complex formation history of the parent body surface. That diversity is quickly masked by alteration once in the terrestrial environment but will need to be considered when samples returned by missions to C-class asteroids are interpreted. Title: Recovery of the Sutter's Mill Meteorite Authors: Jenniskens, P.; Girten, B.; Sears, D.; Sandford, S.; Cooper, G.; Ehrgott, A.; Koop, M.; Albers, J.; Fries, M.; Klotz, D.; Hankey, M.; Schmidt, G.; Worden, P. Bibcode: 2012M&PSA..75.5376J Altcode: On April 22, 2012, a small asteroid scattered carbonaceous chondrites near Sutter's Mill. Peter Jenniskens recovered one fragment pre-rain. NASA Ames Research Center's Lunar Science Institute followed up with organized searches. Title: A Space-Based, Near-Sun Survey to Discover Atira and Aten Orbital Class Near-Earth Objects Authors: Hildebrand, A. R.; Gladman, B.; Tedesco, E. F.; Cardinal, R. D.; Gural, P. S.; Granvik, M.; Larson, S. M.; Chodas, P. W.; Greenstreet, S.; Carroll, K. A.; Brown, P. G.; Wiegert, P.; Worden, S. P.; Wallace, B. J. Bibcode: 2012LPICo1667.6463H Altcode: The NEOSSat spacecraft will efficiently discover Atira and Aten orbital class near-Earth asteroids by searching arcs of sky across the ecliptic plane to within 45 degrees of the Sun. Approximately 10 Atiras are expected to be discovered per year. Title: LAGRANGE: LAser GRavitational-wave ANtenna at GEo-lunar Lagrange points Authors: Conklin, J. W.; Buchman, S.; Aguero, V.; Alfauwaz, A.; Aljadaan, A.; Almajed, M.; Altwaijry, H.; Al-Saud, T.; Balakrishnan, K.; Byer, R. L.; Bower, K.; Costello, B.; Cutler, G. D.; DeBra, D. B.; Faied, D. M.; Foster, C.; Genova, A. L.; Hanson, J.; Hooper, K.; Hultgren, E.; Jaroux, B.; Klavins, A.; Lantz, B.; Lipa, J. A.; Palmer, A.; Plante, B.; Sanchez, H. S.; Saraf, S.; Schaechter, D.; Sherrill, T.; Shu, K. -L.; Smith, E.; Tenerelli, D.; Vanbezooijen, R.; Vasudevan, G.; Williams, S. D.; Worden, S. P.; Zhou, J.; Zoellner, A. Bibcode: 2011arXiv1111.5264C Altcode: We describe a new space gravitational wave observatory design called LAGRANGE that maintains all important LISA science at about half the cost and with reduced technical risk. It consists of three drag-free spacecraft in the most stable geocentric formation, the Earth-Moon L3, L4, and L5 Lagrange points. Fixed antennas allow continuous contact with the Earth, solving the problem of communications bandwidth and latency. A 70 mm diameter AuPt sphere with a 35 mm gap to its enclosure serves as a single inertial reference per spacecraft, which is operated in "true" drag-free mode (no test mass forcing). This is the core of the Modular Gravitational Reference Sensor whose other advantages are: a simple caging design based on the DISCOS 1972 drag-free mission, an all optical read-out with pm fine and nm coarse sensors, and the extensive technology heritage from the Honeywell gyroscopes, and the DISCOS and Gravity Probe B drag-free sensors. An Interferometric Measurement System, designed with reflective optics and a highly stabilized frequency standard, performs the inter-test mass ranging and requires a single optical bench with one laser per spacecraft. Two 20 cm diameter telescopes per spacecraft, each with in-field pointing, incorporate novel technology developed for advanced optical systems by Lockheed Martin, who also designed the spacecraft based on a multi-flight proven bus structure. Additional technological advancements include the drag-free propulsion, thermal control, charge management systems, and materials. LAGRANGE sub-systems are designed to be scalable and modular, making them interchangeable with those of LISA or other gravitational science missions. We plan to space qualify critical technologies on small and nano satellite flights, with the first launch (UV-LED Sat) in 2013. Title: Solar Cycle Fine Structure and Surface Rotation from Ca II K-Line Time Series Data Authors: Scargle, Jeff; Keil, Steve; Worden, Pete Bibcode: 2011sdmi.confE..77S Altcode: Analysis of three and a half decades of data from the NSO/AFRL/Sac Peak K-line monitoring program yields evidence for four components to the variation: (a) the solar cycle, with considerable fine structure and a quasi-periodicity of 122.4 days; (b) a stochastic process, faster than (a) and largely independent of it, (c) a quasi-periodic signal due to rotational modulation, and of course (d) observational errors (shown to be quite small). Correlation and power spectrum analyses elucidate periodic and aperiodic variation of these chromospheric parameters. Time-frequency analysis is especially useful for extracting information about differential rotation, and in particular elucidates the connection between its behavior and fine structure of the solar cycle on approximately one-year time scales. These results further suggest that similar analyses will be useful at detecting and characterizing differential rotation in stars from stellar light-curves such as those being produced by NASA's Kepler observatory. Component (b) consists of variations over a range of timescales, in the manner of a "1/f" random process. A time-dependent Wilson-Bappu effect appears to be present in the solar cycle variations (a), but not in the stochastic process (b). The data can be found at the National Solar Observatory web site http://nsosp.nso.edu/data/cak_mon.html, or by file transfer protocol at ftp://ftp.nso.edu/idl/cak.parameters. Title: Gravity Probe B: Final Results of a Space Experiment to Test General Relativity Authors: Everitt, C. W. F.; Debra, D. B.; Parkinson, B. W.; Turneaure, J. P.; Conklin, J. W.; Heifetz, M. I.; Keiser, G. M.; Silbergleit, A. S.; Holmes, T.; Kolodziejczak, J.; Al-Meshari, M.; Mester, J. C.; Muhlfelder, B.; Solomonik, V. G.; Stahl, K.; Worden, P. W., Jr.; Bencze, W.; Buchman, S.; Clarke, B.; Al-Jadaan, A.; Al-Jibreen, H.; Li, J.; Lipa, J. A.; Lockhart, J. M.; Al-Suwaidan, B.; Taber, M.; Wang, S. Bibcode: 2011PhRvL.106v1101E Altcode: 2011arXiv1105.3456E Gravity Probe B, launched 20 April 2004, is a space experiment testing two fundamental predictions of Einstein’s theory of general relativity (GR), the geodetic and frame-dragging effects, by means of cryogenic gyroscopes in Earth orbit. Data collection started 28 August 2004 and ended 14 August 2005. Analysis of the data from all four gyroscopes results in a geodetic drift rate of -6601.8±18.3mas/yr and a frame-dragging drift rate of -37.2±7.2mas/yr, to be compared with the GR predictions of -6606.1mas/yr and -39.2mas/yr, respectively (“mas” is milliarcsecond; 1mas=4.848×10-9rad). Title: Transiting Exoplanet Survey Satellite (TESS) Authors: Ricker, George R.; Latham, D. W.; Vanderspek, R. K.; Ennico, K. A.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau, D.; Clampin, M.; Deming, L. D.; Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.; Martel, F.; Sasselov, D. D.; Schingler, R. H.; Seager, S.; Torres, G.; Udry, S.; Villasenor, J. N.; Winn, J. N.; Worden, S. P. Bibcode: 2010AAS...21545006R Altcode: 2010BAAS...42..459R TESS is a low-cost SMEX-class satellite mission. In a two-year all-sky survey, TESS will observe more than 2,000,000 nearby stars, searching for temporary drops in brightness caused by planetary transits.

TESS is expected to identify more than 1000 transiting exoplanet candidates, including a sample of about 100 Super Earths---small rock-and-ice planets in the range 1 to 10 Earth masses---orbiting F, G, K, and M dwarfs. TESS's "wide-shallow” survey complements the "narrow-deep” CoRoT and Kepler surveys. TESS-discovered transiting systems will be nearby (< 50 pc), and typically 10-20 x brighter than those discovered by CoRoT and Kepler. Thus, the resulting TESS Transit Catalog will comprise all of the best transiting systems for follow-up observations. TESS will identify Super Earths orbiting IR-bright stars, within reach of JWST spectroscopic searches for planetary water and carbon dioxide.

TESS is a collaborative effort led by researchers at the Massachusetts Institute of Technology, the Harvard-Smithsonian Center for Astrophysics, and the NASA Ames Research Center. Additional TESS scientific partners include Las Cumbres Observatory Global Telescope, Lowell Observatory, the NASA Goddard Space Flight Center, the Infrared Processing and Analysis Center at the California Institute of Technology, the Geneva Observatory (Switzerland), the Tokyo Institute of Technology (Japan), and Institut Supérieur de l'Aéronautique et de l'Espace (France).

TESS was funded by NASA for a Phase A study from May 2008 - June 2009, but was not selected for flight. Additional funding leading to a flight opportunity is being sought. Support has also been provided by the Kavli Foundation, Google, and the Smithsonian Institution. TESS could launch as early as 2013-2014. Title: Polhode Motion, Trapped Flux, and the GP-B Science Data Analysis Authors: Silbergleit, A.; Conklin, J.; DeBra, D.; Dolphin, M.; Keiser, G.; Kozaczuk, J.; Santiago, D.; Salomon, M.; Worden, P. Bibcode: 2010png..book..449S Altcode: No abstract at ADS Title: GP-B Systematic Error Determination Authors: Muhlfelder, B.; Adams, M.; Clarke, B.; Keiser, G. M.; Kolodziejczak, J.; Li, J.; Lockhart, J. M.; Worden, P. Bibcode: 2010png..book..481M Altcode: No abstract at ADS Title: Estimates of the Population of Exoplanets Discoverable by the Transiting Exoplanet Survey Satellite (TESS) Authors: Seager, Sara; Winn, J. N.; Ricker, G. R.; Latham, D. W.; Vanderspek, R. K.; Ennico, K. A.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau, D.; Clampin, M.; Deming, L. D.; Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.; Martel, F.; Sasselov, D. D.; Schingler, R. H.; Torres, G.; Udry, S.; Villasenor, J. N.; Worden, S. P. Bibcode: 2010AAS...21545004S Altcode: 2010BAAS...42R.458S In a two year survey, the Transiting Exoplanet Survey Satellite (TESS) will search the entire sky for planets orbiting nearby, bright stars. In this paper, we calculate the number of transiting planets that TESS will detect, as a function of the properties of the planet and the properties of the host star. The ingredients in this calculation are divided into five groups:

The properties of the planet: its radius r and orbital distance a.

The properties of the star: its luminosity L, mass M, radius R, and number density n in our Galactic neighborhood.

The TESS instrumental parameters: its effective area, bandpass, and limiting photometric precision.

The TESS survey parameters: the characteristics of the input catalog (2.5 million V < 13.5 dwarfs over the whole sky), observing duty cycle (observing a given star 10.3% of the time), and duration of observations for a given star (72 days).

The abundance of planets around stars, which may depend on r, a, and L

The calculation is performed for a three-dimensional grid of planet/star/orbit combinations, in which the three parameters are the planet radius r, the stellar luminosity L, and the orbital distance a. For the range of instrument and population parameters and assumptions considered, we estimate that TESS will detect 1600-2700 planets in total, of which 100-300 should be small planets: SuperEarths or Earths.

Support for this work has been provided by NASA, the Kavli Foundation, Google, and the Smithsonian Institution. Title: Gravity Probe B Data Analysis Authors: Everitt, C. W. F.; Adams, M.; Bencze, W.; Buchman, S.; Clarke, B.; Conklin, J. W.; DeBra, D. B.; Dolphin, M.; Heifetz, M.; Hipkins, D.; Holmes, T.; Keiser, G. M.; Kolodziejczak, J.; Li, J.; Lipa, J.; Lockhart, J. M.; Mester, J. C.; Muhlfelder, B.; Ohshima, Y.; Parkinson, B. W.; Salomon, M.; Silbergleit, A.; Solomonik, V.; Stahl, K.; Taber, M.; Turneaure, J. P.; Wang, S.; Worden, P. W., Jr. Bibcode: 2010png..book...53E Altcode: No abstract at ADS Title: Monte Carlo Simulations of Transit Light Curves for the Transiting Exoplanet Survey Satellite (TESS) Authors: Jernigan, J. G.; Villasenor, J. N.; Ricker, G. R.; Latham, D. W.; Vanderspek, R. K.; Ennico, K. A.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau, D.; Clampin, M.; Deming, L. D.; Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.; Martel, F.; Sasselov, D. D.; Schingler, R. H.; Seager, S.; Torres, G.; Udry, S.; Winn, J. N.; Worden, S. P. Bibcode: 2010AAS...21545003J Altcode: 2010BAAS...42..458J During the Phase A for TESS, simulations of planetary transits were performed to confirm the instrument's ability to detect transits. The simulations cover the full TESS discovery space in the planet period-transit duration plane. Examples included a 36-day period planet, two previously known systems (HAT-P-11 and CoRoT 7B), and one Earth and one SuperEarth. In addition, a broad matrix of planetary periods and transit depths were also simulated. We present simulated light curves of transiting planets that are typical of those that TESS will detect. Each light curve is computed via a Monte Carlo algorithm. The timing of the optical emission includes the parameters of orbital motion for the planet-star system. All simulations include estimates of the noise from the following effects: spacecraft pointing jitter, vignetting, optical PSF wings, background effects, CCD gain and bias instability, sky background, and intrinsic stellar variability. The stellar variability includes a scaled, full temporal power spectrum of the Sun. Typical light curves of planet-star systems are simulated for a 72 day duration with a 10 minute time resolution of each TESS sample. These simulated light curves are analyzed to determine estimates of the S/N for detection for each simulated system. Support for this work has been provided by NASA, the Kavli Foundation, Google, and the Smithsonian Institution. Title: High-Precision Imaging Photometers for the Transient Exoplanet Survey Satellite Authors: Kraft Vanderspek, Roland; Ricker, G. R.; Latham, D. W.; Ennico, K.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau, D.; Clampin, M.; Deming, L.; Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.; Martel, F.; Sasselov, D. D.; Schingler, R. H.; Seager, S.; Szentgyorgyi, A.; Torres, G.; Udry, S.; Villasenor, J. N.; Winn, J. N.; Worden, S. P. Bibcode: 2010AAS...21545007K Altcode: 2010BAAS...42..459K The Transient Exoplanet Survey Satellite (TESS) is designed to search for transiting exoplanet systems around all stars with V < 12. The TESS payload consists of a bank of six identical, wide-field, high-precision imaging photometers. When deployed on the highly-stable TESS satellite platform, these photometers can perform <200 ppm photometry for V=8 stars (∼100 ppm for V=6 stars) in a 10-minute observation. We describe the components of the TESS imaging photometers: the custom, wide-field optics; the large-area CCD arrays; and the low-power, high precision CCD electronics. Support for TESS has been provided by NASA, the Kavli Foundation, Google, and the Smithsonian Institution. Title: Data Network for the TESS Mission Authors: Martel, Francois; Villasenor, J. N.; Ricker, G. R.; Latham, D. W.; Vanderspek, R. K.; Ennico, K. A.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau, D.; Clampin, M.; Deming, L. D.; Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.; Sasselov, D. D.; Schingler, R. H.; Seager, S.; Torres, G.; Udry, S.; Winn, J. N.; Worden, S. P. Bibcode: 2010AAS...21545002M Altcode: 2010BAAS...42..458M The Transiting Exoplanet Survey Satellite (TESS) is designed for an all-sky photometric survey of bright stars, extending&nbspover the entire celestial sphere.&nbspTESS will catalog planetary transits of nearby stars that can be followed-up with ground observatories. The satellite cameras will perform measurements of 2,500,000 stars with brightness ranging from V=4.5 to V=13.5 within two years, and download typically 4.7 G Bytes of data per day.&nbspWe describe the TESS operation plan and the communication and ground system designed to download and process the TESS data. The dedicated ground system uses a network of S-band ground stations spaced around the equator which allows three communications passes per orbit, at data rates of 3.5 Mbit/sec, for up to 45 data downloads per day. Satellite operations and data download are controlled remotely through the internet by the TESS Mission Operation Center at NASA Ames Research Center, which transfers the TESS observation data for processing and distribution to the Science Operation Center managed by &nbspMIT and Harvard-SAO in Cambridge. Support for this work has been provided by NASA, the Kavli Foundation, Google, and the Smithsonian Institution. Title: Transiting Exoplanet Survey Satellite (TESS) Community Observer Program including the Science Enhancement Option Box (SEO Box) - 12 TB On-board Flash Memory for Serendipitous Science Authors: Schingler, Robert; Villasenor, J. N.; Ricker, G. R.; Latham, D. W.; Vanderspek, R. K.; Ennico, K. A.; Lewis, B. S.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau, D.; Clampin, M.; Deming, L. D.; Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.; Martel, F.; Sasselov, D. D.; Seager, S.; Torres, G.; Udry, S.; Winn, J. N.; Worden, S. P. Bibcode: 2010AAS...21545001S Altcode: 2010BAAS...42Q.458S The Transiting Exoplanet Survey Satellite (TESS) will perform an all-sky survey in a low-inclination, low-Earth orbit. TESS's 144 GB of raw data collected each orbit will be stacked, cleaned, cut, compressed and downloaded. The Community Observer Program is a Science Enhancement Option (SEO) that takes advantage of the low-radiation environment, technology advances in flash memory, and the vast amount of astronomical data collected by TESS. The Community Observer Program requires the addition of a 12 TB "SEO Box” inside the TESS Bus. The hardware can be built using low-cost Commercial Off-The-Shelf (COTS) components and fits within TESS's margins while accommodating GSFC gold rules.

The SEO Box collects and stores a duplicate of the TESS camera data at a "raw” stage ( 4.3 GB/orbit, after stacking and cleaning) and makes them available for on-board processing. The sheer amount of onboard storage provided by the SEO Box allows the stacking and storing of several months of data, allowing the investigator to probe deeper in time prior to a given event. Additionally, with computation power and data in standard formats, investigators can utilize data-mining techniques to investigate serendipitous phenomenon, including pulsating stars, eclipsing binaries, supernovae or other transient phenomena.

The Community Observer Program enables ad-hoc teams of citizen scientists to propose, test, refine and rank algorithms for on-board analysis to support serendipitous science. Combining "best practices” of online collaboration, with careful moderation and community management, enables this `crowd sourced’ participatory exploration with a minimal risk and impact on the core TESS Team. This system provides a powerful and independent tool opening a wide range of opportunity for science enhancement and secondary science.

Support for this work has been provided by NASA, the Kavli Foundation, Google, and the Smithsonian Institution. Title: Improved Accuracy of the Gravity Probe B Science Results Authors: Conklin, John; Adams, M.; Aljadaan, A.; Aljibreen, H.; Almeshari, M.; Alsuwaidan, B.; Bencze, W.; Buchman, S.; Clarke, B.; Debra, D. B.; Everitt, C. W. F.; Heifetz, M.; Holmes, T.; Keiser, G. M.; Kolodziejczak, J.; Li, J.; Lipa, J.; Lockhart, J. M.; Muhlfelder, B.; Parkinson, B. W.; Salomon, M.; Silbergleit, A.; Solomonik, V.; Stahl, K.; Taber, M.; Turneaure, J. P.; Worden, P. W., Jr. Bibcode: 2010cosp...38.3734C Altcode: 2010cosp.meet.3734C This paper presents the progress in the science data analysis for the Gravity Probe B (GP-B) experiment. GP-B, sponsored by NASA and launched in April of 2004, tests two fundamental predictions of general relativity, the geodetic effect and the frame-dragging effect. The GP-B spacecraft measures the non-Newtonian drift rates of four ultra-precise cryogenic gyroscopes placed in a circular polar Low Earth Orbit. Science data was collected from 28 August 2004 until cryogen depletion on 29 September 2005. The data analysis is complicated by two unexpected phenomena, a) a continually damping gyroscope polhode affecting the calibration of the gyro readout scale factor, and b) two larger than expected classes of Newtonian torque acting on the gyroscopes. Experimental evidence strongly suggests that both effects are caused by non-uniform electric potentials (i.e. the patch effect) on the surfaces of the gyroscope rotor and its housing. At the end of 2008, the data analysis team reported intermediate results showing that the two complications are well understood and are separable from the relativity signal. Since then we have developed the final GP-B data analysis code, the "2-second Filter", which provides the most accurate and precise determination of the non-Newtonian drifts attainable in the presence of the two Newtonian torques and the fundamental instrument noise. This limit is roughly 5 Title: Gravity Probe B Data Analysis. Status and Potential for Improved Accuracy of Scientific Results Authors: Everitt, C. W. F.; Adams, M.; Bencze, W.; Buchman, S.; Clarke, B.; Conklin, J. W.; Debra, D. B.; Dolphin, M.; Heifetz, M.; Hipkins, D.; Holmes, T.; Keiser, G. M.; Kolodziejczak, J.; Li, J.; Lipa, J.; Lockhart, J. M.; Mester, J. C.; Muhlfelder, B.; Ohshima, Y.; Parkinson, B. W.; Salomon, M.; Silbergleit, A.; Solomonik, V.; Stahl, K.; Taber, M.; Turneaure, J. P.; Wang, S.; Worden, P. W. Bibcode: 2009SSRv..148...53E Altcode: This is the first of five connected papers detailing progress on the Gravity Probe B (GP-B) Relativity Mission. GP-B, launched 20 April 2004, is a landmark physics experiment in space to test two fundamental predictions of Einstein’s general relativity theory, the geodetic and frame-dragging effects, by means of cryogenic gyroscopes in Earth orbit. Data collection began 28 August 2004 and science operations were completed 29 September 2005. The data analysis has proven deeper than expected as a result of two mutually reinforcing complications in gyroscope performance: (1) a changing polhode path affecting the calibration of the gyroscope scale factor C g against the aberration of starlight and (2) two larger than expected manifestations of a Newtonian gyro torque due to patch potentials on the rotor and housing. In earlier papers, we reported two methods, ‘geometric’ and ‘algebraic’, for identifying and removing the first Newtonian effect (‘misalignment torque’), and also a preliminary method of treating the second (‘roll-polhode resonance torque’). Central to the progress in both torque modeling and C g determination has been an extended effort on “Trapped Flux Mapping” commenced in November 2006. A turning point came in August 2008 when it became possible to include a detailed history of the resonance torques into the computation. The East-West (frame-dragging) effect is now plainly visible in the processed data. The current statistical uncertainty from an analysis of 155 days of data is 5.4 marc-s/yr (∼14% of the predicted effect), though it must be emphasized that this is a preliminary result requiring rigorous investigation of systematics by methods discussed in the accompanying paper by Muhlfelder et al. A covariance analysis incorporating models of the patch effect torques indicates that a 3-5% determination of frame-dragging is possible with more complete, computationally intensive data analysis. Title: Polhode Motion, Trapped Flux, and the GP-B Science Data Analysis Authors: Silbergleit, A.; Conklin, J.; Debra, D.; Dolphin, M.; Keiser, G.; Kozaczuk, J.; Santiago, D.; Salomon, M.; Worden, P. Bibcode: 2009SSRv..148..397S Altcode: Magnetic field trapped in the Gravity Probe B (GP-B) gyroscope rotors contributes to the scale factor of the science readout signal. This contribution is modulated by the rotor’s polhode motion. In orbit, polhode period was observed to change due to a small energy dissipation, which significantly complicates data analysis. We present precise values of spin phase, spin down rate, polhode phase and angle, and scale factor variations obtained from the data by Trapped Flux Mapping. This method finds the (unique) trapped field distribution and rotor motion by fitting a theoretical model to the harmonics of high (gyroscope spin) frequency signal. The results are crucial for accurately determining the gyroscope relativistic drift rate from the science signal. Title: GP-B Systematic Error Determination Authors: Muhlfelder, B.; Adams, M.; Clarke, B.; Keiser, G. M.; Kolodziejczak, J.; Li, J.; Lockhart, J. M.; Worden, P. Bibcode: 2009SSRv..148..429M Altcode: We have evaluated the systematic error in the GP-B experiment using five different approaches and estimated the individual contributions of many error sources. The systematic effects we consider include those due to gyroscope torques, gyroscope readout, telescope readout, and guide star proper motion. Effects with an estimated impact on the experiment error larger than 1 mas/yr are discussed in detail. Examples of analyses that bound other sources to less than 1 mas/yr are included to show the range of techniques employed to perform this work. We describe the remaining tasks to complete the systematic error analysis and estimate the total experiment uncertainty. Title: Transiting Exoplanet Survey Satellite (TESS) Authors: Ricker, George R.; Latham, D. W.; Vanderspek, R. K.; Ennico, K. A.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau, D.; Clampin, M.; Deming, L. D.; Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.; Martel, F.; Sasselov, D. D.; Schingler, R. H.; Seager, S.; Torres, G.; Udry, S.; Villasenor, J. S.; Winn, J. N.; Worden, S. P. Bibcode: 2009AAS...21430605R Altcode: The Transiting Exoplanet Survey Satellite (TESS) is a low cost, SMEX-class planet finder. In a two year all-sky survey, TESS will observe more than two million bright, nearby stars, searching for temporary drops in brightness that are caused by planetary transits. Such transits not only provide the means of identifying the planet, but also provide knowledge of the planet's diameter, mass density, surface gravity, temperature, and other key properties. TESS is expected to detect more than 1000 transiting exoplanet candidates. These detections will include a sample of 100 Super Earths -- small rock-and-ice planets with masses in the range 1 to 10 Earth masses -- orbiting nearby stars with spectral types spanning a broad range, including F, G, K, and M dwarfs. No ground-based survey can achieve this feat. TESS's "wide-shallow" survey complements the "narrow-deep" Corot and Kepler mission surveys. The resulting TESS Transit Catalog of the nearest and brightest stars in the sky will constitute a unique scientific legacy for followup observations. TESS will identify Super Earths orbiting IR-bright stars, ideal for JWST searches for planetary water and carbon dioxide.

The TESS mission is a collaborative effort led by researchers at the Massachusetts Institute of Technology, the Harvard-Smithsonian Center for Astrophysics, and the NASA Ames Research Center. Additional TESS partners include ATK Space Systems, the Las Cumbres Observatory Global Telescope Network, Lowell Observatory, the NASA Goddard Space Flight Center, the Infrared Processing and Analysis Center at the California Institute of Technology, the University of California (Berkeley and Santa Cruz), the SETI Institute, Espace Incorporated, the Geneva Observatory (Switzerland), the Tokyo Institute of Technology (Japan), and Institut Supérieur de l'Aéronautique et de l'Espace (France).

TESS is currently completing a NASA-funded Phase A study, and is proposed for launch in December 2012. Title: ASIMA -- Asteroid Impact Analyzer: A Proposed Close-to-Home Planetary Mission to Probe the Diversity of Comets and Asteroids Authors: Jenniskens, P.; Dissly, R.; Boyd, I. D.; Revelle, D. O.; Nuth, J. A.; Worden, S. P. Bibcode: 2009LPI....40.2305J Altcode: The proposed Asteroid Impact Analyzer (ASIMA) is a Partner Mission of Opportunity that will measure how the bulk carbon-to-metal ratio varies among comets and asteroids. Title: The impact and recovery of asteroid 2008 TC3 Authors: Jenniskens, P.; Shaddad, M. H.; Numan, D.; Elsir, S.; Kudoda, A. M.; Zolensky, M. E.; Le, L.; Robinson, G. A.; Friedrich, J. M.; Rumble, D.; Steele, A.; Chesley, S. R.; Fitzsimmons, A.; Duddy, S.; Hsieh, H. H.; Ramsay, G.; Brown, P. G.; Edwards, W. N.; Tagliaferri, E.; Boslough, M. B.; Spalding, R. E.; Dantowitz, R.; Kozubal, M.; Pravec, P.; Borovicka, J.; Charvat, Z.; Vaubaillon, J.; Kuiper, J.; Albers, J.; Bishop, J. L.; Mancinelli, R. L.; Sandford, S. A.; Milam, S. N.; Nuevo, M.; Worden, S. P. Bibcode: 2009Natur.458..485J Altcode: In the absence of a firm link between individual meteorites and their asteroidal parent bodies, asteroids are typically characterized only by their light reflection properties, and grouped accordingly into classes. On 6 October 2008, a small asteroid was discovered with a flat reflectance spectrum in the 554-995nm wavelength range, and designated 2008 TC3 (refs 4-6). It subsequently hit the Earth. Because it exploded at 37km altitude, no macroscopic fragments were expected to survive. Here we report that a dedicated search along the approach trajectory recovered 47 meteorites, fragments of a single body named Almahata Sitta, with a total mass of 3.95kg. Analysis of one of these meteorites shows it to be an achondrite, a polymict ureilite, anomalous in its class: ultra-fine-grained and porous, with large carbonaceous grains. The combined asteroid and meteorite reflectance spectra identify the asteroid as F class, now firmly linked to dark carbon-rich anomalous ureilites, a material so fragile it was not previously represented in meteorite collections. Title: The Transiting Exoplanet Survey Satellite (TESS) Authors: Ricker, George R.; Latham, D. W.; Vanderspek, R. K.; Ennico, K. A.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau, D.; Deming, L. D.; Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.; Martel, F.; Sasselov, D. D.; Schingler, R. H.; Seager, S.; Torres, G.; Udry, S.; Villasenor, J. S.; Winn, J. N.; Worden, S. P. Bibcode: 2009AAS...21340301R Altcode: 2009BAAS...41..193R The Transiting Exoplanet Survey Satellite (TESS) is a low cost, SMEX-class planet finder. In a two year all-sky survey, TESS will observe more than two million bright, nearby stars, searching for temporary drops in brightness that are caused by planetary transits, which occur when a planet's orbit carries it directly in front of its parent star. Such transits not only provide the means of identifying the planet, but also provide knowledge of the planet's diameter, mass density, surface gravity, temperature, and other key properties.

TESS is expected to catalog more than 1000 transiting exoplanet candidates--20 times as many as are presently known, including a sample of 'super Earths'. The TESS "wide-shallow" survey will be complementary to the "narrow-deep" ones of the Corot and Kepler missions: its sky coverage will exceed that of Corot by 1000 times, and that of Kepler by 400 times. Because the TESS all-sky survey will systematically examine every interesting bright star likely to harbor an exoplanet, the resulting TESS Transit Catalog will constitute a unique scientific legacy. High resolution, follow-up ground-based optical and space-based IR spectroscopy of exoplanets demands bright targets. Thus, TESS should identify those new exoplanets that are ideal for study with the world's largest ground-based telescopes, as well as with NASA's upcoming James Webb Space Telescope.

The TESS mission is a collaborative effort led by researchers at MIT, the Harvard-Smithsonian Center for Astrophysics, and the NASA Ames Research Center. Additional TESS partners include the NASA Goddard Space Flight Center, the Harvard Origins of Life Initiative, Lowell Observatory, Caltech's IPAC, the SETI Institute, Geneva Observatory in Switzerland, Tokyo Institute of Technology, SUPAERO in France, ATK Space, Espace Inc, and the Las Cumbres Observatory Global Telescope Network. TESS has been accepted for Phase A study by NASA, and is proposed for launch in late 2012. Title: Astronomy Enabled by Ares V -- A Workshop Authors: Lester, Daniel F.; Langhoff, S.; Worden, S. P.; Thronson, H.; Correll, R. Bibcode: 2009AAS...21345008L Altcode: 2009BAAS...41R.343L On April 26th and 27th, 2008, NASA Ames Research Center hosted a two-day weekend workshop entitled "Astronomy Enabled by Ares V.” The primary goal of the workshop was to begin the process of bringing the Ares V designers together with senior representatives of the astronomical community to discuss the feasibility of using the Ares V heavy-lift launch vehicle to enable both new astronomical telescope architectures and new science. When developed in the latter part of the upcoming decade Ares V will be by far the most capable launch vehicle, with mass and volume launch capability many times that now available. The vehicle is understood to be the main workhorse in carrying humans and cargo to the Moon and beyond and, as such, is a key lynchpin for NASA's new space transportation architecture. Participants included experts from academia, industry, and NASA, including representatives of the Constellation architecture. Participants considered, in the context of identified astronomy needs: (1) Are there telescope concepts or missions capable of breakthrough science that are either enabled or significantly enhanced by the capabilities of an Ares V? (2) What demands do large telescopes place on the payload environment of the Ares V, such as mass, volume, fairing shape, cleanliness, acoustics, etc.? (3) What technology and environmental issues need to be addressed to facilitate launching observatories on an Ares V? (4) Is there a trade-off between mass and complexity that could reduce launch risk and, thereby, the cost of building large telescopes? We report on the results of this workshop, which included discussion on the operations model for such large-investment astronomical facilities. Such an operations model might well involve human and or robotic maintenance and servicing, in order to fully capitalize on the science potential of such facilities. Title: The Large Benefits of Small Satellite Missions Authors: Baker, Daniel N.; Worden, S. Pete; Buchman, S.; Byer, Robert; DeBra, Dan; Mester, John Bibcode: 2009astro2010P..67B Altcode: 2009astro2010P..67W No abstract at ADS Title: Step Prototype Development Status Authors: Mehls, C.; Bayart, C.; Bower, J.; Clarke, B.; Cox, C.; Gill, D.; Stricker, D.; Vora, N.; Wang, S.; Zhou, P.; Torii, R.; Worden, P.; Debra, D.; Dittus, H.; Loeffler, F. Bibcode: 2008mgm..conf.2553M Altcode: STEP, the Satellite Test of the Equivalence Principle [1], proposes to test the Equivalence Principle to a part in 1018 by comparing the free-fall acceleration of cylindrical shaped test masses [2] in Earth orbit. Magnetic bearings constrain the test mass motion to their axis of symmetry [3]. The displacement of the test masses is measured using a DC SQUID and superconducting coils [4], enabling a displacement sensitivity as small as 10-15 m. In combination with a small spring stiffness a differential acceleration sensitivity of 10-18 g is achievable. Residual satellite acceleration is reduced to better than 10-14 g by compensating satellite drag forces with thrust provided by helium gas.

We report on recent progress in the development of STEP prototype flight accelerometers, in particular the development of the high precision quartz housing for the engineering inner accelerometer and the testing of SQUID and capacitive readout systems using 'brass board' accelerometer prototypes. Title: Constraining the Atira Orbital Class (IEO`s) Asteroid Population with the Near Earth Object Surveillance Satellite (NEOSSat) Mission Authors: Hildebrand, Alan; Tedesco, E.; Cardinal, R.; Gladman, B.; Matthews, J.; Wallace, B.; Larson, S.; Gural, P.; Chodas, P.; Granvik, M.; Wiegert, P.; Brown, P.; Worden, S.; Carroll, K. Bibcode: 2008DPS....40.5207H Altcode: 2008BAAS...40..493H The Atira orbital class of NEO's (by definition) always occurs inside Earth's orbit, and can only be found at relatively low solar elongations by ground-based searches. The latter surveys have succeeded in discovering 9 Atiras to date, but the discovery rate can be substantially augmented using a space-based telescope designed to image near the Sun. The NEOSSat microsatellite is designed to search the ecliptic plane at 45 to 55° solar elongation and ±40; degrees ecliptic latitude; near-Sun surveying is considerably compromised by zodiacal light brightness in visible wavelengths, but even lower elongations could be profitably searched. The spacecraft is a derivative of the Microvariablity and Oscillations of Stars (MOST) microsatellite weighing 65 kg with a 15 cm aperture f5.88 Maksutov telescope, and will be deployed in a Sun synchronous orbit. The spacecraft is a dual use mission and will also be used to image high Earth orbit artificial satellites. Under favourable circumstances the asteroid search project will cover 1200 square degrees of sky per month with limiting V magnitudes of 20. Planned survey cadence will be 4 images over 125 minutes; this cadence is tied to the NEOSSat orbital period of 100 minutes. A space-based telescope benefits from relatively low backgrounds, "continuous” and predictable availability, and the ability to use parallax to discriminate NEO's from the Main Belt population by determining distances to all NEO discoveries; a space-based sensor has the disadvantage of comparatively long slew times between fields. NEOSSat will be able to discover approximately one third of the Atira population >1; km in diameter in a 3 year survey (the spacecraft will detect Atiras to 18.5 H magnitude); 50% of the >1; km diameter Aten class population will be detected during the same interval. Title: The Large Benefits of Small-Satellite Missions Authors: Baker, Daniel N.; Worden, S. Pete Bibcode: 2008EOSTr..89..301B Altcode: Small-spacecraft missions play a key and compelling role in space-based scientific and engineering programs [Moretto and Robinson, 2008]. Compared with larger satellites, which can be in excess of 2000 kilograms, small satellites range from 750 kilograms-roughly the size of a golf cart-to less than 1 kilogram, about the size of a softball. They have been responsible for greatly reducing the time needed to obtain science and technology results. The shorter development times for smaller missions can reduce overall costs and can thus provide welcome budgetary options for highly constrained space programs. In many cases, we contend that 80% (or more) of program goals can be achieved for 20% of the cost by using small-spacecraft solutions. Title: A Cryogenic Liquid-Mirror Telescope on the Moon to Study the Early Universe Authors: Angel, Roger; Worden, Simon P.; Borra, Ermanno F.; Eisenstein, Daniel J.; Foing, Bernard; Hickson, Paul; Josset, Jean-Luc; Bui Ma, Ki; Seddiki, Omar; Sivanandam, Suresh; Thibault, Simon; van Susante, Paul Bibcode: 2008ApJ...680.1582A Altcode: 2008arXiv0806.2241A We have studied the feasibility and scientific potential of zenith observing liquid-mirror telescopes having 20-100 m diameters located on the Moon. They would carry out deep infrared surveys to study the distant universe and follow up discoveries made with the 6 m James Webb Space Telescope (JWST), with more detailed images and spectroscopic studies. They could detect objects 100 times fainter than JWST, observing the first high-redshift stars in the early universe and their assembly into galaxies. We explored the scientific opportunities, key technologies, and optimum location of such telescopes. We have demonstrated critical technologies. For example, the primary mirror would necessitate a high-reflectivity liquid that does not evaporate in the lunar vacuum and remains liquid at less than 100 K. We have made a crucial demonstration by successfully coating an ionic liquid that has negligible vapor pressure. We also successfully experimented with a liquid mirror spinning on a superconducting bearing, as will be needed for the cryogenic, vacuum environment of the telescope. We have investigated issues related to lunar locations, concluding that locations within a few kilometers of a pole are ideal for deep sky cover and long integration times. We have located ridges and crater rims within 0.5° of the north pole that are illuminated for at least some sun angles during lunar winter, providing power and temperature control. We also have identified potential problems, like lunar dust. Issues raised by our preliminary study demand additional in-depth analyses. These issues must be fully examined as part of a scientific debate that we hope to start with the present article. Title: Gravity Probe B data analysis status and potential for improved accuracy of scientific results Authors: Everitt, C. W. F.; Adams, M.; Bencze, W.; Buchman, S.; Clarke, B.; Conklin, J.; DeBra, D. B.; Dolphin, M.; Heifetz, M.; Hipkins, D.; Holmes, T.; Keiser, G. M.; Kolodziejczak, J.; Li, J.; Lockhart, J. M.; Muhlfelder, B.; Parkinson, B. W.; Salomon, M.; Silbergleit, A.; Solomonik, V.; Stahl, K.; Turneaure, J. P.; Worden, P. W., Jr. Bibcode: 2008CQGra..25k4002E Altcode: Gravity Probe B (GP-B) is a landmark physics experiment in space designed to yield precise tests of two fundamental predictions of Einstein's theory of general relativity, the geodetic and frame-dragging effects, by means of cryogenic gyroscopes in Earth orbit. Launched on 20 April 2004, data collection began on 28 August 2004 and science operations were completed on 29 September 2005 upon liquid helium depletion. During the course of the experiment, two unexpected and mutually-reinforcing complications were discovered: (1) larger than expected 'misalignment' torques on the gyroscopes producing classical drifts larger than the relativity effects under study and (2) a damped polhode oscillation that complicated the calibration of the instrument's scale factor against the aberration of starlight. Steady progress through 2006 and 2007 established the methods for treating both problems; in particular, an extended effort from January 2007 on 'trapped flux mapping' led in August 2007 to a dramatic breakthrough, resulting in a factor of ~20 reduction in data scatter. This paper reports results up to November 2007. Detailed investigation of a central 85-day segment of the data has yielded robust measurements of both relativity effects. Expansion to the complete science data set, along with anticipated improvements in modeling and in the treatment of systematic errors may be expected to yield a 3 6% determination of the frame-dragging effect. Title: The Near Earth Object Surveillance Satellite (NEOSSat) Mission Will Conduct an Efficient Space-Based Asteroid Survey at Low Solar Elongations Authors: Hildebrand, A. R.; Tedesco, E. F.; Carroll, K. A.; Cardinal, R. D.; Matthews, J. M.; Gladman, B.; Kaiser, N. R.; Brown, P. G.; Wiegert, P.; Larson, S. M.; Worden, S. P.; Wallace, B. J.; Chodas, P. W.; Granvik, M.; Gural, P. Bibcode: 2008LPICo1405.8293H Altcode: No abstract at ADS Title: UARC/NASA Near Earth Object Small Spacecraft Summer Program Authors: Asphaug, E.; Delory, G. T.; Korycansky, D.; Marchis, F.; de Pater, I.; Hines, J.; Worden, P.; 2008 S4P Summer Students Bibcode: 2008LPICo1405.8386A Altcode: No abstract at ADS Title: Small Spacecraft in Support of the Lunar Exploration Program Authors: Worden, S. P.; Weston, A. R. Bibcode: 2007LPICo1371.3019W Altcode: 2007eelo.work.3019W No abstract at ADS Title: Deposition of metal films on an ionic liquid as a basis for a lunar telescope Authors: Borra, Ermanno F.; Seddiki, Omar; Angel, Roger; Eisenstein, Daniel; Hickson, Paul; Seddon, Kenneth R.; Worden, Simon P. Bibcode: 2007Natur.447..979B Altcode: An optical/infrared telescope of 20-100m aperture located on the Moon would be able to observe objects 100 to 1,000 times fainter than the proposed next generation of space telescopes. The infrared region of the spectrum is particularly important for observations of objects at redshifts z>7. The apparent simplicity and low mass of a liquid mirror telescope, compared with a traditional pointable glass mirror, suggest that the concept should be considered further. A previously proposed liquid mirror telescope, based upon a spinning liquid metallic alloy, is not appropriate for infrared applications, which will require a liquid below 130K. Here we report the successful coating of an ionic liquid with silver. The surface is smooth and the silver coating is stable on a timescale of months. The underlying ionic liquid does not evaporate in a vacuum and remains liquid down to a temperature of 175K. Given that there are ~106 simple and ~1018 ternary ionic liquids, it should be possible to synthesize liquids with even lower melting temperatures. Title: The Near Earth Object Surveillance Satellite (NEOSSat) Mission Enables an Efficient Space-Based Survey (NESS Project) of Interior-to-Earth-Orbit (IEO) Asteroids Authors: Hildebrand, A. R.; Tedesco, E. F.; Carroll, K. A.; Cardinal, R. D.; Matthews, J. M.; Kuschnig, R.; Walker, G. A. H.; Gladman, B.; Kaiser, N. R.; Brown, P. G.; Larson, S. M.; Worden, S. P.; Wallace, B. J.; Chodas, P. W.; Muinonen, K.; Cheng, A.; Gural, P. Bibcode: 2007LPI....38.2372H Altcode: The NEOSSat microsatellite will be used to discover and track NEOs with an emphasis on interior-to-Earth-orbit objects. Title: STEP (satellite test of the equivalence principle) Authors: Sumner, T. J.; Anderson, J.; Blaser, J. -P.; Cruise, A. M.; Damour, T.; Dittus, H.; Everitt, C. W. F.; Foulon, B.; Jafry, Y.; Kent, B. J.; Lockerbie, N.; Loeffler, F.; Mann, G.; Mester, J.; Pegrum, C.; Reinhardt, R.; Sandford, M.; Scheicher, A.; Speake, C. C.; Torii, R.; Theil, S.; Touboul, P.; Vitale, S.; Vodel, W.; Worden, P. W. Bibcode: 2007AdSpR..39..254S Altcode: STEP is one of a number of missions now being developed to take advantage of the quiet space environment to carry out very sensitive gravitational experiments. Using pairs of concentric free-falling proof-masses, STEP will be able to test the equivalence principle (EP) to a sensitivity at least five orders of magnitude better than currently achievable on ground. The EP is a founding principle of general relativity and STEP is the most sensitive experiment of this type planned so far, aiming at 1 part in 10 18. Title: Low-Cost Small Spacecraft for Multiple Asteroid Studies Authors: Worden, S. P.; Correll, R. C. Bibcode: 2006LPICo1325...78W Altcode: No abstract at ADS Title: A Lunar Liquid Mirror Telescope (LLMT) for deep-field infrared observations near the lunar pole Authors: Angel, Roger; Eisenstein, Dan; Sivanandam, Suresh; Worden, Simon P.; Burge, Jim; Borra, Ermanno; Gosselin, Clément; Seddiki, Omar; Hickson, Paul; Ma, Ki Bui; Foing, Bernard; Josset, Jean-Luc; Thibault, Simon; Van Susante, Paul Bibcode: 2006SPIE.6265E..1UA Altcode: 2006SPIE.6265E..54A We have studied the feasibility and scientific potential of a 20 - 100 m aperture astronomical telescope at the lunar pole, with its primary mirror made of spinning liquid at less than 100K. Such a telescope, equipped with imaging and multiplexed spectroscopic instruments for a deep infrared survey, would be revolutionary in its power to study the distant universe, including the formation of the first stars and their assembly into galaxies. The LLMT could be used to follow up discoveries made with the 6 m James Webb Space Telescope, with more detailed images and spectroscopic studies, as well as to detect objects 100 times fainter, such as the first, high-red shift stars in the early universe. Our preliminary analysis based on SMART-1 AMIE images shows ridges and crater rims within 0.5° of the North Pole are illuminated for at least some sun angles during lunar winter. Locations near these points may prove to be ideal for the LLMT. Lunar dust deposited on the optics or in a thin atmosphere could be problematic. An in-situ site survey appears necessary to resolve the dust questions. Title: Access to Space: A Strategy for the Twenty-First Century Authors: Worden, Simon; Sponable, Jess Bibcode: 2006AstPo...4...69W Altcode: No abstract at ADS Title: STEP Accelerometer Response under Non-Equilibrium Conditions Authors: Wang, S.; Ambekar, P.; Bayart, C.; Torii, R.; Worden, P.; Debra, D. Bibcode: 2006cosp...36.3462W Altcode: 2006cosp.meet.3462W The STEP Satellite Test of the Equivalence Principle accelerometer performance is derived under the assumption that the test mass is properly constrained and positioned 5DOF in the housing cavity test mass is in the operational sweet-spot It is extremely useful to check system response when the mass is outside the sweet-spot Using a 1m long fiber suspended test mass we have made past studies on magnetic suspension forces Fy and Fz and have explored the housing cavity in 3DOF x y and z translation limited by uncertainty in test mass tilt angle qy and qz To address this limitation we have recently constructed a 2-axis cryogenic tilt platform The laboratory version of position readout electronics allow us to measure the test mass position at 4K to a precision of 1 nm and tilt angle to less than 1 arc sec in 100 seconds We will present recent experimental data showing the dynamic response of the capacitance measurement subsystem as a function of test mass position Title: STEP Baseline Design and Validation Authors: Torii, R.; Kolodziejczak, J.; Worden, P.; Step Team Bibcode: 2006cosp...36.3595T Altcode: 2006cosp.meet.3595T STEP Satellite Test of the Equivalence Principle proposes to test the Equivalence Principle to a part in 10 18 by comparing the free-fall acceleration of test masses in orbit about the Earth The baseline design goal is to resolve a difference in acceleration of 4x10 -19 g in approximately 10 5 s Demonstrating this level of sensitivity by a test on the ground is not possible limited by seismic and other disturbances An analysis of the acceleration measurement subsystem shows more than adequate sensitivity and an extensive system analysis in which external disturbances and the effect of other subsystems are included in a self-consistent model has also shown that the baseline design goal can be achieved Our approach to validate the baseline design is to focus on verifying the assumptions used in analysis We will discuss how this approach has been implemented in our recent manufacture and test of prototype accelerometers and in our future plans for prototype instrument testing Title: The Demise of US Spacepower: Not with a Bang but a Whimper Authors: Correll, Randall; Worden, Simon Bibcode: 2005AstPo...3..233C Altcode: No abstract at ADS Title: Testable lightweight telescopes for space Authors: Angel, Roger; Burge, Jim; Worden, S. P. Bibcode: 2005SPIE.5899..325A Altcode: The next generation of larger space optics will need lightweight and deployed mirror systems in order to control costs and fit within current and planned launch vehicle fairings. These will require active control based on wavefront sensing to establish and maintain their optical quality. Such control has been the enabling factor for the current generation of 8 m class ground-based telescopes, whose mirrors are either single monoliths with detailed shape control or have multiple rigid segments with control of relative position. They use actuator densities of typically a few per square meter. For active space systems it will be highly desirable to test the full deployed spacecraft in a vacuum test with a scene simulator, to validate before launch the optical performance of the complete system with its closed loop control systems. To enable such testing, the space mirror system must be designed from the start to work in a 1g as well as zero g environment. The orientation we envisage has the spacecraft system pointed at the zenith, illuminated by a downward beam collimated with reference to a full aperture liquid flat. We consider here two space mirror systems. The first has rigid segments supported by position actuators to control only rigid body motions. Since the segments under test must hold their shape with an axial 1g load and no passive flotation supports, they must be smaller than for ground systems. If made of lightweighted silicon carbide or beryllium for diffraction limited imaging in the optical, they would have to be ~ 30 cm in diameter. A mirror systems made from such segments will require about 40 actuators and wavefront sensor sub-apertures per square meter. The second system is a lightweight 3.5x8 m monolith for very high contrast imaging, as is envisaged for NASA's Terrestrial Planet Finder. High accuracy control of Fourier components down to ~ 0.2 m period is required, requiring a deformable mirror with about 4000 actuators. If the primary itself is the deformable element, and has a 1 cm thick glass meniscus facesheet weighing 600 kg, the gravity-induced quilting during testing would be about 1 nm rms, low enough for ground testing of the complete system at the desired 10-10 contrast level. Title: A Deep-Field Infrared Observatory Near the Lunar Pole Authors: Borra, E. F.; Seddiki, O.; Angel, J. R. P.; Worden, S. P.; Eisenstein, D.; Silvanandam, S.; Hickson, P.; Ma, K. Bibcode: 2005JRASC..99R.134B Altcode: A study has been made of the feasibility and scientific potential of a 20-to 100-m aperture astronomical telescope at the lunar pole, with its primary mirror made of spinning liquid at < 100 K. Such a telescope, equipped with imaging and multiplexed spectroscopic instruments for a deep-infrared survey, would be revolutionary in its power to study the distant Universe, including the formation of the first stars and their assembly into galaxies. Our study explored the scientific opportunities, key technologies, and optimum location of such a Lunar Liquid Mirror Telescope (LLMT). An optical design for a 20- m telescope with diffraction limited imaging over a 15-arcminute field has been developed. It would be used to follow up on discoveries made with the 6-m James Webb Space Telescope, with more detailed images and spectroscopic studies, as well as to detect objects 100 times fainter, such as the first high-redshift star in the early Universe. Amodel was made of a liquid mirror spinning on a superconducting bearing, as will be needed for the cryogenic, vacuum environment of the LLMT. Reflective silver coatings have been deposited for the first time on a liquid surface, needed to make infrared mirrors at ~80 K. Issues relating to polar locations have been explored. Dust on the optics or in a thin atmosphere, though unlikely to be problematic at the poles, should be investigated in-situ. Issues relating to polar locations have been explored. Locations at or within a few km of a pole are preferred for deep-sky cover, and allow for long integration times by simple instrument rotation. This revolutionary mission concept could provide a scientific focus to NASA's planned exploration of the Moon, just as currently HST stands as a major achievement of its Shuttle Program. Title: Leadership for new US strategic directions Authors: Worden, Simon P.; Correll, Randall R. Bibcode: 2005SpPol..21...21W Altcode: Although faced with the new global challenges of terrorism and peer competition, the USA has been slow to adapt its cold war forces, and newer 'warfighter' strategy to meet them. Cyberspace and outer space offer the means to do this, via 'responsive' microsatellites and low-cost launchers, and broadband internet information and education services. The US military leadership is, however, not well enough versed in these technologies, with senior personnel largely lacking a space or technical background and having little appetite for change. If the USA is successfully to meet current challenges, it must first create a leadership that is technologically capable and philosophically attuned to change. Title: Advantages of Searching for Asteroids from Low Earth Orbit: the NEOSSat Mission Authors: Hildebrand, A. R.; Carroll, K. A.; Tedesco, E. F.; Faber, D. R.; Cardinal, R. D.; Matthews, J. M.; Kuschnig, R.; Walker, G. A. H.; Gladman, B.; Pazder, J.; Brown, P. G.; Larson, S. M.; Worden, S. P.; Wallace, B. J.; Chodas, P. W.; Muinonen, K.; Cheng, A. Bibcode: 2004EM&P...95...33H Altcode: 2005EM&P...95...33H Space-based observatories have several advantages over ground-based observatories in searching for asteroids and comets. In particular, the Aten and Interior to Earth’s Orbit (IEO) asteroid classes may be efficiently sought at low solar elongations along the ecliptic plane. A telescope in low Earth orbit has a sufficiently long orbital baseline to determine the parallax for all Aten and IEO class asteroids discovered with this observing strategy. The Near Earth Object Space Surveillance Satellite (NEOSSat) mission will launch a microsatellite to exploit this observing strategy complementing ground-based search programmes. Title: Step (satellite Test of the Equivalence Principle) Authors: Sumner, T. J.; Everitt, C. W. F.; Mester, J.; Torii, R.; Worden, P.; Lockerbie, N.; Pegrum, C.; Anderson, J.; Mann, G.; Blaser, J. -P.; Cruise, A. M.; Speake, C. C.; Damour, T.; Vitale, S.; Dittus, H.; Foulon, B.; Touboul, P.; Kent, B. J.; Sandford, M.; Jafry, Y.; Reinhardt, R.; Loeffler, F.; Vodel, W. Bibcode: 2004apsp.conf..148S Altcode: STEP is one of a number of missions now being developed to take advantage of the quiet space environment to carry out very sensitive gravitational experiments. Using pairs of concentric free-falling proof-masses, STEP will be able to test the Equivalence Principle (EP) to a sensitivity at least five orders of magnitude better than currently achievable on ground. The EP is a founding principle of general relativity and STEP is the most sensitive experiment of this type planned so far, aiming at 1 part in 1018. Title: Testing STEP Accelerometers Using Fiber Suspended Test Mass Authors: Wang, S.; Cordouan, J.; Torii, R.; Worden, P. Bibcode: 2004cosp...35.3175W Altcode: 2004cosp.meet.3175W STEP (Satellite Test of the Equivalence Principle) proposes to test the Equivalence Principle to one part in 1018 by comparing the rate of fall of test mass pairs in Earth orbit. Test mass acceleration is determined by displacement measurement under known spring stiffness. The STEP accelerometer has one primary axis of measurement (sensitive axis) defined very precisely by superconducting magnetic bearings. First qualitative measurements of forces produced by prototype flight bearings were performed in 2002. The bearing was tested by trapping a fixed persistent current, and then measuring the resulting static radial forces on a test mass (forces orthogonal to the accelerometer sensitive axis). The test mass was suspended by a meter long fiber with the cryogenic apparatus platform under 1-axis tilt control. We will present recent test data and our plans for a future major upgrade to improve performance and increase dynamic testing capabilities. Title: The NASA-ESA MiniSTEP payload Authors: Worden, P. W.; Torii, R.; Everitt, C. W. F. Bibcode: 2003AdSpR..32.1379W Altcode: The Equivalence Principle, which states that gravitational mass and inertial mass are different ways of measuring the same property, is the experimental foundation for modern gravitational theory. Modern theory cannot reconcile gravity with the other fundamental forces. One possibility is that the present theory of gravity, general relativity, is incomplete or incorrect. If this is the case, the Equivalence Principle may be violated at some level beyond the one part in 10 12 that has been experimentally verified. The goal of the Satellite Test of the Equivalence Principle (STEP) is to improve this result to better than one part in 10 18. In STEP two or more concentric, cylindrical test masses "fall" around the Earth in a drag-free satellite. The masses are cooled to < 2K and supported by frictionless, superconducting, linear bearings. Ultra-sensitive SQUID position detectors measure their relative motion. A confirmed violation could provide key information toward the possible unification of the four fundamental forces; conversely, a null result can rule out competing theories or constrain new theories. MiniSTEP is the least expensive mission proposed to date that still achieves STEP's basic scientific goal. It compares four different materials in four differential accelerometers. Cost saving is achieved by operating the accelerometers sequentially, thereby avoiding duplicated equipment. The drag-free satellite will be built around an existing superfluid helium dewar and a small, semi-production spacecraft. A small commercial launch vehicle will place the satellite in a 400 km, sun-synchronous, polar, Earth orbit. Nominal mission lifetime is four months - but a six to eight month life is expected. Title: The flux of small near-Earth objects colliding with the Earth Authors: Brown, P.; Spalding, R. E.; ReVelle, D. O.; Tagliaferri, E.; Worden, S. P. Bibcode: 2002Natur.420..294B Altcode: Asteroids with diameters smaller than ~50-100m that collide with the Earth usually do not hit the ground as a single body; rather, they detonate in the atmosphere. These small objects can still cause considerable damage, such as occurred near Tunguska, Siberia, in 1908. The flux of small bodies is poorly constrained, however, in part because ground-based observational searches pursue strategies that lead them preferentially to find larger objects. A Tunguska-class event-the energy of which we take to be equivalent to 10 megatons of TNT-was previously estimated to occur every 200-300 years, with the largest annual airburst calculated to be ~20 kilotons (kton) TNT equivalent (ref. 4). Here we report satellite records of bolide detonations in the atmosphere over the past 8.5 years. We find that the flux of objects in the 1-10-m size range has the same power-law distribution as bodies with diameters >50m. From this we estimate that the Earth is hit on average annually by an object with ~5kton equivalent energy, and that Tunguska-like events occur about once every 1,000 years. Title: Mitigation of near-earth object impacts Authors: Worden, S.; Brown, P. Bibcode: 2002cosp...34E.440W Altcode: 2002cosp.meetE.440W As our ability to survey and catalog potentially threatening Near-Earth Objects (NEOs) grows we will inevitably find some that are potentially threatening. Numerous authors have conjectured about potential mitigation schemes. These schemes include destruction or diversion via nuclear or chemical explosives if time is short. In the case of much longer warning times low-thrust diversion schemes, some taking advantage of natural effects such as radiation pressure have been forwarded. Others advocate focusing our efforts on passive schemes analogous to nuclear warfare civil defense. However, any effective mitigation scheme should follow proven military operations precepts. These include equal attention to decision making and command and control organizations and technology. As we consider serious approaches to NEO impact mitigation we must pay equal or greater attention to how decisions will be made and mission control exercises as we do to the more exciting "weapons." Title: The size of meteoroid constituent grains: Implications for interstellar meteoroids Authors: Hawkes, R. L.; Campbell, M. D.; Leblanc, A. G.; Parker, L.; Brown, P.; Jones, J.; Worden, S. P.; Correll, R. R.; Woodworth, S. C.; Fisher, A. A.; Gural, P.; Murray, I. S.; Connors, M.; Montague, T.; Jewell, D.; Babcock, D. D. Bibcode: 2002dsso.conf...23H Altcode: 2002IAUCo.181...23H No abstract at ADS Title: The STEP mission: principles and baseline design Authors: Mester, J.; Torii, R.; Worden, P.; Lockerbie, N.; Vitale, S.; Everitt, C. W. F. Bibcode: 2001CQGra..18.2475M Altcode: The Satellite Test of the Equivalence Principle (STEP) will test the equality of fall of objects in Earth orbit to an accuracy approaching one part in 108 by measuring the difference in rate of fall of test cylinders in cryogenic differential accelerometers in a drag-free satellite. This paper describes the current baseline design and principles used in the design of the STEP mission. Title: STEP error model development Authors: Worden, P.; Mester, J.; Torii, R. Bibcode: 2001CQGra..18.2543W Altcode: We describe the ongoing development of a comprehensive error model for the satellite test of the equivalence principle, STEP. The goal is to employ a model of the experiment and apparatus as a self-consistent whole. The model uses a set of input parameters based on experiment design and the measured characteristics of STEP sensor systems. The output of the model evaluates specific disturbances to the test masses in the general categories of thermal noise, gas pressure forces, electrical forces, magnetic forces, gravitational forces, radiation pressure and vibration. Use of the model to set experiment requirements and to evaluate design trade-offs are briefly discussed. Title: The Near-Earth Space Surveillance (NESS) Mission: Discovery, Tracking, and Characterization of Asteroids, Comets, and Artificial Satellites with a Microsatellite Authors: Hildebrand, A. R.; Carroll, K. A.; Balam, D. D.; Cardinal, R. D.; Matthews, J. M.; Kuschnig, R.; Walker, G. A. H.; Brown, P. G.; Tedesco, E. F.; Worden, S. P.; Burrell, D. A.; Chodas, P. W.; Larson, S. M.; Spahr, T. B.; Wallace, B. J. Bibcode: 2001LPI....32.1790H Altcode: The Near-Earth Space Surveillance (NESS) Mission, a microsatellite dedicated to observing near-Earth (NEO) and interior-to-the-Earth (IEO)asteroids and comets plus artificial satellites, is currently being studied under contract to the Canadian Space Agency. Title: Image-intensified video results from the 1998 Leonid shower: I. Atmospheric trajectories and physical structure Authors: Campbell, M. D.; Brown, P. G.; Leblanc, A. G.; Hawkes, R. L.; Jones, J.; Worden, S. P.; Correll, R. R. Bibcode: 2000M&PS...35.1259C Altcode: Two station electro-optical observations of the 1998 Leonid shower are presented. Precise heights and light curves were obtained for 79 Leonids which ranged in brightness (at maximum luminosity) from +0.3 to +6.1 astronomical magnitude. The mean photometric mass of the data sample was 1.4x10-6 kg. The dependence of astronomical magnitude at peak luminosity on photometric mass and zenith angle was consistent with earlier studies of faint sporadic meteors. For example, a Leonid meteoroid with a photometric mass of about 1.0x10-7 kg corresponds to a peak meteor luminosity of about +4.5 astronomical magnitudes. The mean beginning height of the Leonid meteors in this sample was 112.6 km and the mean ending height was 95.3 km. The highest beginning height observed was 144.3 km. There is relatively little dependence of either the first or last heights on mass, which is indicative of meteoroids which have clustered into constituent grains prior to the onset of intensive grain ablation. The height distribution, combined with numerical modelling of the ablation of the meteoroids, suggests that silicate-like materials are not the principle component of Leonid meteoroids, and hints at the presence of a more volatile component. Light curves of many Leonids were examined for evidence of the physical structure of the associated meteoroids: like the 1997 Leonids, the narrow, nearly symmetric curves imply that the meteoroids are not solid objects. The light curves are consistent with a dustball structure. Title: Evidence for transverse spread in Leonid meteors Authors: LeBlanc, A. G.; Murray, I. S.; Hawkes, R. L.; Worden, P.; Campbell, M. D.; Brown, P.; Jenniskens, P.; Correll, R. R.; Montague, T.; Babcock, D. D. Bibcode: 2000MNRAS.313L...9L Altcode: We report here evidence for significant transverse spread of the light production region in bright Leonid meteors. One Leonid meteor has an apparent spread in the light production region of about 600m perpendicular to the flight path for the meteor, that transverse spread persisting for at least 0.3s. We have also detected short-duration, jet-like features emanating from a bright Leonid meteor recorded in 1998. These jet-like features have maximum spatial dimensions up to 1.9km. While we cannot definitively rule out instrumental artefacts as a cause for these jet-like features, they may be evidence of motion contributing to the observed spatial spread in the light production region. Title: The 1998 International Leonid Expedition. Authors: Brown, P.; Campbell, M.; Jones, J.; Webster, A. R.; Hawkes, R.; Leblanc, A.; Murray, I.; Ellis, K.; Correll, R.; Worden, S. P.; Bedard, M.; Jewell, D.; Montague, T.; Thorne, J.; Tilton, B.; Gural, P.; Babcock, D.; Worsfold, R.; Connors, M.; Hildebrand, A. R.; Molau, S.; Rendtel, J.; Sponder, R.; Baayraa, T.; Batmunkh, D.; Bekhtur, B.; Garradd, K. G.; McNaught, R. H.; Beech, M. Bibcode: 2000JRASC..94...24B Altcode: No abstract at ADS Title: USAF Perspectives on Leonid Threat and Data Gathering Campaigns Authors: Treu, Marvin H.; Worden, Simon P.; Bedard, Michael G.; Bartlett, Randall K. Bibcode: 2000lsr..book...27T Altcode: No abstract at ADS Title: Global Ground-Based Electro-Optical and Radar Observations of the 1999 Leonid Shower: First Results Authors: Brown, P.; Campbell, M. D.; Ellis, K. J.; Hawkes, R. L.; Jones, J.; Gural, P.; Babcock, D.; Barnbaum, C.; Bartlett, R. K.; Bedard, M.; Bedient, J.; Beech, M.; Brosch, N.; Clifton, S.; Connors, M.; Cooke, B.; Goetz, P.; Gaines, J. K.; Gramer, L.; Gray, J.; Hildebrand, A. R.; Jewell, D.; Jones, A.; Leake, M.; Leblanc, A. G.; Looper, J. K.; Mcintosh, B. A.; Montague, T.; Morrow, M. J.; Murray, I. S.; Nikolova, S.; Robichaud, J.; Spondor, R.; Talarico, J.; Theijsmeijer, C.; Tilton, B.; Treu, M.; Vachon, C.; Webster, A. R.; Weryk, R.; Worden, S. P. Bibcode: 2000lsr..book..167B Altcode: No abstract at ADS Title: The Step Payload and Experiment Authors: Worden, P.; Torii, R.; Mester, J. C.; Everitt, C. W. F. Bibcode: 2000fps..conf.1205W Altcode: No abstract at ADS Title: The STEP Payload and Experiment Authors: Worden, P.; Torii, R.; Mester, J. C.; Everitt, C. W. F. Bibcode: 2000AdSpR..25.1205W Altcode: The foundation of modern gravitational theory is the Equivalence Principle. General Relativity is incompatible with theories of other fundamental forces such as QED, suggesting that it is incomplete. For example, there may be additional forces coupled to baryon number or spin. In this case the Equivalence Principle may be violated below the experimentally verified level of one part in 1012. A violation could provide crucial information for new theories. A team of US and European scientists has assembled to do the Satellite Test of the Equivalence Principle (STEP) with the goal of improving this measurement to 1 part in 1018. In STEP two or more test masses ``fall'' around the earth in a drag free satellite. A difference in the rate of fall appears as a periodic difference in their acceleration. The test masses are cooled to less than 2K and are supported by frictionless superconducting bearings. Ultra-sensitive SQUID position sensors measure their relative motion and their common motion is removed by adjustments during acceleration maneuvers. Any Equivalence Principle signal is separated from major disturbances by rotation of the spacecraft. STEP is planned to be launched by 2004, with nominal mission lifetime of 6 months Title: The Leonids 1998 results and implications for the future. Authors: Hawkes, R.; Connors, M.; Hildebrand, A. R.; Ellis, K. J.; Molau, S.; Rendtel, J.; Baayraa, T.; Batmunkh, D.; Bekhtur, B.; Leblanc, A.; Murray, I.; Sponder, R.; Beech, M.; Gural, P.; Thorne, J.; Bedard, M.; Correll, R.; Jewell, D.; Montague, T.; Tilton, B.; Worden, S. P.; Brown, P.; Campbell, M.; Jones, J.; Webster, A. R.; Babcock, D.; Worsfold, R.; Jenniskens, P.; Garradd, G.; McNaught, R. H. Bibcode: 1999JRASC..93Q.176H Altcode: No abstract at ADS Title: Global Ground-Based Electro-Optical and Radar Observations of the 1999 Leonid Shower: First Results Authors: Brown, P.; Campbell, M. D.; Ellis, K. J.; Hawkes, R. L.; Jones, J.; Gural, P.; Babcock, D.; Barnbaum, C.; Bartlett, R. K.; Bedard, M.; Bedient, J.; Beech, M.; Brosch, N.; Clifton, S.; Connors, M.; Cooke, B.; Goetz, P.; Gaines, J. K.; Gramer, L.; Gray, J.; Hildebrand, A. R.; Jewell, D.; Jones, A.; Leake, M.; LeBlanc, A. G.; Looper, J. K.; McIntosh, B. A.; Montague, T.; Morrow, M. J.; Murray, I. S.; Nikolova, S.; Robichaud, J.; Spondor, R.; Talarico, J.; Theijsmeijer, C.; Tilton, B.; Treu, M.; Vachon, C.; Webster, A. R.; Weryk, R.; Worden, S. P. Bibcode: 1998EM&P...82..167B Altcode: 2000EM&P...82..167B No abstract at ADS Title: USAF Perspectives on Leonid Threat and Data Gathering Campaigns Authors: Treu, Marvin H.; Worden, Simon P.; Bedard, Michael G.; Bartlett, Randall K. Bibcode: 1998EM&P...82...27T Altcode: 2000EM&P...82...27T The Air Force has long recognized the threat posed by the space environment to military satellite systems including the potential for disastrous effects resulting from a meteoroid impact. This concern has steadily elevated with our nation's increasing reliance on space assets for systems critical to national defense. The 1998/1999 Leonid Meteor Storm Operational Monitoring Program was initiated to address this threat. The goal of this Air Force-led, international cooperative program was to provide near real-time Leonid meteor flux measurements to satellite operators. The incorporation of these measurements with model predictions provided an approximate 2-hour lead warning of the peak storm activity, permitting satellite operators ample opportunity to exercise hazard mitigation procedures. As a result, Department of Defense (DoD) and other participating satellite operators may have helped avoid spacecraft damage. The extent of any minor damage to components impossible to detect by operators is difficult to ascertain and may not manifest itself for a period of time. Modest micrometeoroid precipitation may reduce spacecraft life expectancies as a consequence of the physical erosion or sandblasting of exterior surfaces, and damage sustained by electronic systems from concurrent high-energy plasma discharges. Later effects could take the form of premature failure of satellite sensors and other spacecraft components, leading to overall shortening of satellite mission duration. The Air Force intends to pursue further analysis of data and polling of satellite operators to fully assess the Leonid '99 event. Future U.S. Air Force involvement may include support for additional observations and analysis. Title: Differential accelerometer testing Authors: Sapilewski, G.; Worden, P.; Bye, M. Bibcode: 1996CQGra..13A.165S Altcode: Ground-based testing and qualification of the STEP differential accelerometers is important for instrument development and overall mission success. A facility for testing the various subsystems of the flight accelerometer, including the superconducting magnetic bearings, is under development at Stanford University. Achieving the required sensitivity led to the development of an apparatus comprising cryogenics, a multiple degree-of-freedom tipper table, an active control system, electrostatic suspension and a capacitive sensing system. Title: Accelerometer development at Stanford Authors: Worden, P. W.; Bye, M. Bibcode: 1996CQGra..13A.155W Altcode: Preflight prototype differential accelerometers for STEP are being developed at Stanford under NASA funding. Subsystem development in progress includes work on thin-film superconducting circuits deposited on cylinders, SQUID-based superconducting position measurement and electrostatic positioning and charge control. A thorough programme of testing and qualification of the subsystems is an essential part of the experiment. We have built a flux microscope and magnetometer probe to study magnetic flux motion, one of the limiting factors in the accelerometers; a position sensor study facility; a tipper table for testing and qualification of bearings in three degrees of freedom and a `mechatronics' lab for the manufacture of critical circuits on cylinders. Title: Detection of Meteoroid Impacts by Optical Sensors in Earth Orbit Authors: Tagliaferri, E.; Spalding, R.; Jacobs, C.; Worden, S. P.; Erlich, A. Bibcode: 1994hdtc.conf..199T Altcode: No abstract at ADS Title: Technical challenges of Satellite Test of the Equivalence Principle mission. Authors: Mason, P. V.; Israelsson, U. E.; Petrac, D.; Jackson, H. W.; Worden, P.; Parmley, R. Bibcode: 1993Cryo...33..390M Altcode: The Satellite Test of the Equivalence Principle (STEP) experiment is being proposed to improve our knowledge of the equivalence of inertial and gravitational mass by a factor of 106, yielding a crucial test of one of the fundamental postulates of Einstein's theory of general relativity. The experiment will use six differential superconducting accelerometers in a spacecraft in low Earth orbit. The accelerometers will each contain two proof masses of different densities. If the equivalence principle is violated, the masses will oscillate with respect to each other at the orbital frequency. The mission will last six months and is planned for launch in 2000. The entire experiment must be cooled to 1.8K and must be held to this level within 1mK per orbit. A crucial requirement is that any disturbances in the orbital frequency must generate gravitational variation signals much less than the expected signal. One source of such disturbance is the motion of the liquid helium in the local gravity gradient field, which rotates at orbital frequency with respect to the spacecraft. An electrostatic confinement system has been proposed for this purpose. This system will be described. A back-up system using the superfluid fountain effect will also be discussed. Title: Satellite test of the equivalence principle. Authors: Worden, P. W., Jr. Bibcode: 1993rges.conf...43W Altcode: 1993rges.rept...43W The essential features of an orbiting equivalence principle experiment (STEP) are described. In addition to a test of this fundamental principle to one part in 1017, the instrument makes possible an improved measurement of the gravitational constant, improved geodetic measurements of the Earth, aeronomy measurements with high sensitivity and time resolution, and an engineering evaluation for further development of drag-free spacecraft. Title: Spectroscopic and Photometric Observations of a Five-Magnitude Flare Event on UV CETI Authors: Eason, Erik L. E.; Giampapa, M. S.; Radick, R. R.; Worden, S. P.; Hege, E. K. Bibcode: 1992AJ....104.1161E Altcode: Optical observations of a 5-mag flare in the U band on UV Ceti (dM5.6e) at both spectral and temporal resolutions are presented. A strong violet continuum which cannot be reproduced solely with a thermal bremsstrahlung spectrum is seen. The energy emitted by the flare in the U band is about 5.0 x 10 exp 31 ergs. The corresponding total flare energy in white light is estimated to be 1.2 x 10 exp 32 ergs. This estimate, combined with the 700-s duration of the U-band event, yields an average white-light flare luminosity which is about 3 percent of the quiescent stellar bolometric luminosity. Strong H-alpha wings appeared after the impulsive phase. A discernible central reversal is present in both the quiescent H-alpha profile and, significantly, in the flare profile following the impulsive phase. It is suggested that the site of H-alpha flare emission is not necessarily associated with a compact, high pressure region. The flare-enhanced line emission arises from large flare volumes that are, in turn, a distinguishing feature of stellar flares of this magnitude. Title: Remote Sensing: The Inconsistency of U. S. Space Policy Authors: Worden, Simon P.; Katz, Jordan S. Bibcode: 1992PrAA..144..369W Altcode: No abstract at ADS Title: On Self-Licking Ice Cream Cones Authors: Worden, S. P. Bibcode: 1992ASPC...26..599W Altcode: 1992csss....7..599W No abstract at ADS Title: STEP. A Satellite Test of the Equivalence Principle. Authors: Reinhard, R.; Worden, P. W.; Everitt, C. W. F. Bibcode: 1991EN.....22..216R Altcode: STEP aims to determine any difference in the rate of fall of test masses in an Earth-orbiting satellite to one part in 1017 of the total gravitational acceleration - a 106 factor improvement over existing measurements. Title: Gradiometry coexperiments to the gravity probe B and step missions Authors: Tapley, M.; Breakwell, J.; Everitt, C. W. F.; van Patten, R.; Worden, P. Bibcode: 1991AdSpR..11f.179T Altcode: 1991AdSpR..11..179T The Gravity Probe B spacecraft, designed to test predictions of general relativity, will fly in the mid 1990's. It will carry four electrostatically suspended gyroscopes in a cryogenic environment and will have a drag-free control system to minimize disturbances on the gyroscopes. The Stanford Test of Equivalence Principle (STEP) spacecraft, to fly later, will carry a set of test masses under very similar conditions. This paper explores the possibility of using differential measurements of the GP-B gyroscope suspension forces and the STEP test mass displacement readout to form single-axis gravity gradiometers. We show that the noise in the suspension systems is sufficiently small in the relevant frequency range, and that enough information is collected to compensate for the spacecrafts' attitude motion. Finally, using Breakwell's ``flat-earth'' approximation, we compare these experiments to other geodesy experiments and predict the contribution they can make to the knowledge of the Earth's geopotential. Title: a Satellite Test of the Equivalence Principle Authors: Worden, P. W., Jr. Bibcode: 1989grg..conf..542W Altcode: No abstract at ADS Title: Almost exactly Zero: the equivalence principle. Authors: Worden, P. W., Jr. Bibcode: 1988nznf.conf..766W Altcode: Contents: 1. Introduction: the equivalence principle; conceptual development and historical background. 2. The orbital experiment. 3. The ground-based experiment: general description; period matching and position subtraction; magnetic bearing; position detectors; a 200 m pendulum. 4. Status and conclusion. Title: Why Astronomers Should Love Sdi Authors: Worden, S. P. Bibcode: 1987S&T....74..340W Altcode: No abstract at ADS Title: Magnetic Field Measurements on the Sun and Implications for Stellar Magnetic Field Observations Authors: Sun, Wei-Hsin; Giampapa, Mark S.; Worden, Simon P. Bibcode: 1987ApJ...312..930S Altcode: Results of solar magnetic field measurements in plages, sunspot umbrae, and sunspot penumbrae using high spectral resolution, unpolarized infrared H band spectral data are presented. A Fourier deconvolution analysis scheme similar to that utilized for stellar magnetic field measurements is adopted. As an example, a field strength of 3240 + or - 450 G is determined in a sunspot umbra combined with a value of 2000 + or - 180 G in the associated penumbra. These values are compared with a direct measurement of the spot umbra and penumbra field strengths based on the observed separation of the Zeeman components of the magnetically sensitive lines. Possible origins for the discrepancy between the results inferred by these two different techniques are discussed. The Fourier analysis results confirm the widespread occurrence of kilogauss level fields in the solar photosphere. The implications of the solar results for stellar magnetic field measurements are considered. Title: Coordinated Magnetic and Chromospheric/Coronal Synoptic Observations Authors: Worden, Simon P. Bibcode: 1984iue..prop.1906W Altcode: We propose to obtain time-resolved, coordinated observations of magnetic flux and the associated coronal emission as well as chromospheric and transition region line emission for selected active chromospheric stars. The unique data to be obtained in this program will provide a crucial input to theories that describe the heating of stellar chromospheres and coronae. In essence, the results to be acquired through the observations will establish a preliminary empirical relationship between stellar photospheric magnetic field strengths and magnetic flux, stellar coronal field strength and emission, and stellar outer atmospheric line emission. We are presently utilizing demonstrated methods to directly detect magnetic fields on stellar surfaces. We are also able to deduce coronal field strengths from X-ray or radio observations. Magnetic results indicate the existence of strong (a few kilogauss) fields that may cover up to 80% of the stellar surface. Moreover, these fields are observed to rapidly (2-3 days) vary in surface coverage, suggesting a single large magnetic spot complex on only one hemisphere of the star. We therefore propose a coordinated IUE ground-based synoptic program to obtain chromospheric-transition region data (with IUE), and photospheric and coronal magnetic field and flux measurements (ground-based observations) for several stars that exhibit rapidly varying surface field coverages over their rotational periods. Our IUE observing pattern will primarily consist of low dispersion, SWP observations and high-dispersion, LWR exposures. These data will be obtained simultaneously (or near simultaneously) with ground-based optical, IR and radio observations. The ground-based data will be used to infer magnetic field strengths and flux in the photosphere and corona. We also require that the IUE shifts be scheduled every third day to insure that we examine the entire stellar surface over 10-15 day rotational periods. We require two separate observing periods in order to access all objects in the target list from ground-based observing sites. Title: A photometric study of the cataclysmic variable, LX Serpentis. Authors: Eason, E. L. E.; Worden, S. P.; Klimke, A.; Africano, J. L. Bibcode: 1984PASP...96..372E Altcode: A high-speed photometric study of the cataclysmic variable star LX Serpentis has been performed, using a 1.2 m synoptic telescope in white light. By means of a second-order least squares fitting of the eclipse times, an orbital period of about 0.158 hr was derived. The shapes of the eclipse light curves indicate that the hot-spot brightness morphology can be irregular, and it can change in a time scale of days. An analysis of the power-spectrum reveals a low signal-to-noise ratio peak at about 0.007 Hz (about 140 sec), but in general no evidence was found for periodic or quasi-periodic oscillations in the power spectrum. Title: The response of chromospheric emission lines to flares on YZ Canis Minoris. Authors: Worden, S. P.; Schneeberger, T. J.; Giampapa, M. S.; Deluca, E. E.; Cram, L. E. Bibcode: 1984ApJ...276..270W Altcode: Six flares of the dMe star YZ CMi have been observed with simultaneous photometry and high-dispersion, time-resolved spectroscopy.The spectra have temporal resolutions of 3 minutes with spectral resolutions of 0.24 Å. The largest observed flare had a U band amplitude of 1.5 mag. Hα and Hβ line profiles did not broaden during any of the observed flares, although the line center intensity increased by over a factor of 2 during some flares. After the initial increase in intensity, the emission line strength decreases but remains at enhanced levels for hours following U band flares. The Hα flare luminosity and total energy are compared to corresponding properties of solar flares. Title: Variations in the solar calcium K line 1976-1982 Authors: Keil, S. L.; Worden, S. P. Bibcode: 1984ApJ...276..766K Altcode: Chromospheric variability between 1976 and 1982 as evidenced in Ca II K line observations obtained at Sacramento Peak Observatory is reported. The data on solar variability are compared to similar data collected at Kitt Peak by White and Livingston (1981). The measurement of solar rotation as reflected in the K index was attempted. Partial success was achieved in this second objective, based on limited results in early 1977 and early 1981-1982. While there is good long term (about 6 months) correlation between the K line and the number of plages and sunspots during the rising phase of solar activity, the short term correlation (about 1 week) is poor. Title: High-speed digital signal processing for speckle interferometry. Authors: Hege, E. K.; Cocke, W. J.; Strittmatter, P. A.; Worden, S. P.; Booth, W. C. Bibcode: 1984SPIE..445..469H Altcode: Speckle interferometry has now been shown capable of yielding diffraction limited information on objects as faint as visual magnitude 16. The instrumentation proposed will improve spatial resolution at visible wavelengths to approximately 15 milliarc-seconds (75×10-9radians, the best possible for any existing telescope), reduce detector induced image distortion to less than 1% and increase the throughput to essentially real-time complex Fourier transform amplitude and phase integrations at the telescope. Title: Magnetic Field Measurements on the Sun and Synthesis of Stellar Spectrum from Solar Data Authors: Sun, W.; Giampapa, M. S.; Worden, S. P. Bibcode: 1983BAAS...15..952S Altcode: No abstract at ADS Title: The photometric variability of solar-type stars. III. Results from 1981-82, including parallel observations of thirty-six Hyades stars. Authors: Radick, R. R.; Mihalas, D.; Lockwood, G. W.; Thompson, D. T.; Warnock, A., III; Hartmann, L. W.; Worden, S. P.; Henry, G. W.; Sherlin, J. M. Bibcode: 1983PASP...95..621R Altcode: A photometric survey of main-sequence stars in the Pleiades, Hyades, and Malmquist Field, to investigate variability among solar-type stars, had been continued at Cloudcroft Observatory for a second season. Possibly six of 40 Pleiades stars, two (possibly six) of 49 Hyades stars and possibly four of 42 stars in the Malmquist Field are found to be variable. Parallel observations of Hyades stars were obtained also at Lowell Observatory. These measurements, which achieved better precision, reveal significiant variations in eleven (possibly 16) of 36 Hyades stars, all of spectral type F7 V-K2 V. Agreement between the two surveys is acceptable. The two seasons of the Cloudcroft survey show that changes in the mean annual brightness of the Hyades stars accompany changes in the amplitude of their short-term variability, in the sense that a star tends to become fainter as its variability increases and vice versa. Color effects are absent. Title: The photometric variability of solar-type stars. II. Stars selected from Wilson's chromospheric activity survey. Authors: Radick, R. R.; Wilkerson, M. S.; Worden, S. P.; Africano, J. L.; Klimke, A.; Ruden, S.; Rogers, W.; Armandroff, T. E.; Giampapa, M. S. Bibcode: 1983PASP...95..300R Altcode: The authors have observed eleven solar-type main-sequence stars to search for continuum variability. Stars were selected from Wilson's chromospheric activity survey, and were observed for periods of three to six months with intermediate-band Stroemgren uvby photometry. The authors find evidence that two of these eleven stars are variable and that one other may be. Comparison with contemporaneous Ca II H + K emission flux measurements shows that the amplitude of photometric variability correlates strongly with both the mean emission flux and the amplitude of its variation. Variations in continuum light and emission flux tend to correlate in time, as well, with continuum minima coinciding with emission maxima and vice-versa. The authors infer that the surface activity of these stars tends to be confined to localized activity centers that include both emission plages and dark spots, similar to the active regions observed on the sun. Title: The magnetic field on the RS Canum Venaticorum star lambda Andromeda. Authors: Giampapa, M. S.; Golub, L.; Worden, S. P. Bibcode: 1983ApJ...268L.121G Altcode: A program to detect and measure magnetic flux on the surfaces of late-type stars is discussed. A technique is adopted to deconvolve magnetically insensitive lines from similar, magnetically sensitive lines to infer the degree of Zeeman splitting in the latter lines. These measurements yield values for the magnetic field strength and filling factor (flux). To illustrate the approach, observations of the RS CVn star Lambda And are presented. At the epoch of observation, 1981 April 26, a field strength of 1290 + or - 320 gauss covering 48 + or - 7 percent of this star's surface is found. This measurement compares with an estimate of coronal magnetic flux in the cooler component of the stellar corona of 1110 gauss with a coronal volume filling factor of 75 percent, based on X-ray data for Lambda And. Title: Using small aperture interferometry to detect planets in nearby binary star systems Authors: Currie, D. G.; McAlister, H. A.; Schneeberger, T. J.; Worden, S. P. Bibcode: 1983STIN...8331551C Altcode: If suitably accurate binary star orbits can be observed, the effects of planets in the binary star system may be detectable in the reflex motion of the component binary stars. We show that interferometric measurements of binary star systems will provide this information. We discuss the effects of the atmosphere on degrading images and how interferometry will remove these effects to provide very accurate binary star positions relative to the other components in the binary system. Two systems, amplitude interferometry and speckle interferometry, can accomplish this using existing telescopes and techniques. With these methods, nearly accuracies of 0.00002 arc second are possible for binaries of 1 arc second separation and 10000 arc second for a 5 arc binary. These accuracies are more than enough to detect planets in orbits like Jupiter's out to over 20 pc. There are 188 observable systems within 20 pc, in most of which it is possible to have stable planetary orbits similar to solar system orbits. With advanced data recording systems it is possible to observe binary systems where the components are as faint as +16 stellar magnitudes. A dedicated 2-meter interferometric telescope to monitor binary stars could be built for about 1.4 million dollars. Title: Stellar and Planetary Photometry at Cloudcroft Observatory Authors: Worden, S. P. Bibcode: 1983IAPPP...9..120W Altcode: For the last four years there has been an extensive program at the Cloudcroft 48 inch photometric observatory to study the question of luminosity variability in the sun and solar-type stars. The author gives a summary of this program's results and urges small photoelectric observatory to consider assisting in this program. Title: Eclipse timings in U Geminorum. Authors: Eason, E. L. E.; Africano, J. L.; Klimke, A.; Quigley, R. J.; Rogers, W.; Worden, S. P. Bibcode: 1983PASP...95...58E Altcode: Seventeen new timings of primary eclipse minimum for the dwarf nova, U Gem, are reported. The orbital period of the binary system is seen as quasi-periodic. Among the possible causes of the ephemeris variability are nonconservative mass transfer, nonconservation of orbital angular momentum, the relative motion of the hot spot within the system, apsidal motion, and the existence of a third star. U Gem is found to exhibit the following interesting features: flickering (indicating possible spasmodic mass transfer); the probable existence of a disk, allowing storage of considerable rotational angular momentum; occasional swelling of the disk, suggesting variable momentum storage; and outbursts. Title: Methods and results for detecting magnetic fields on late-type stars. Authors: Giampapa, M. S.; Worden, S. P. Bibcode: 1983IAUS..102...29G Altcode: A program to detect and measure magnetic flux on the surfaces of late-type stars is discussed. A novel technique is adopted to deconvolve magnetically insensitive lines from similar, magnetically sensitive lines to infer the degree of Zeeman splitting in the latter lines. These measurements yield values for the magnetic field strength and filling factor (flux). To illustrate the approach multiple observations are presented of the RS CVn star Lambda And. At the epoch of observation 26 April 1981 a field strength of 1290 + or - 50 gauss covering 48 + or - 2 percent of this stars's surface is found. Observations at other epochs clearly demonstrate magnetic flux variability on Lambda And. Title: Optical and ultraviolet stellar flare spectroscopy Authors: Worden, S. P. Bibcode: 1983ASSL..102..207W Altcode: 1983ards.proc..207W; 1983IAUCo..71..207W As for solar flares, one of the most physically revealing types of data for M-dwarf flares are high-resolution, time-resolved spectra. Due to the intrinsically faint nature of the M-dwarf stars, spectroscopic data has tended to be of low spectral (approximately 5 A) and temporal (approximately 5 min) resolution. However, with the development of image intensified spectrographs and fast, efficient digital detectors, the last several years have seen the successful acquisition of both high time and spectral resolution M-dwarf flare spectra. Recent programs have also been successfully conducted using the International Ultraviolet Explorer satellite to obtain UV and EUV spectra of M-dwarf flares. These data reveal that dwarf M star flares are remarkably similar to solar flares in all aspects of their spectroscopic phenomenology. Title: Cryogenic Equivalence Principle Experiment: discussion and present status. Authors: Worden, P. W., Jr. Bibcode: 1983mgm..conf..771W Altcode: The Weak Equivalence Principle is the hypothesis that the ratio of passive gravitational mass to inertial mass is the same for all bodies regardless of their composition. This principle has a fundamental place in physics as the experimental basis for Einstein's Strong Equivalence Principle, which is a postulate of General Relativity. This paper describes the present state of the Stanford Orbital Equivalence Principle Experiment. Title: The photometric variability of solar-type stars. I. Preliminary results for the Pleiades, Hyades and the Malmquist field. Authors: Radick, R. R.; Hartmann, L.; Mihalas, D.; Worden, S. P.; Africano, J. L.; Klimke, A.; Tyson, E. T. Bibcode: 1982PASP...94..934R Altcode: The young main sequence stars in the Pleiades and Hyades clusters, and old disk stars in the Malmquist Field near the north galactic pole, have been observed by precision photometry in order to determine the prevalance of variability among solar type stars. Significant variations have been found in at least five, and possibly ten, of 44 Hyades stars, and possibly one of the 41 stars in the Malmquist Field, all of which are of spectral type F8 V-K2 V. 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: Stellar model chromospheres. XIII. M dwarf stars. Authors: Giampapa, M. S.; Worden, S. P.; Linsky, J. L. Bibcode: 1982ApJ...258..740G Altcode: Single-component, homogeneous model chromospheres that are consistent with high-resolution profiles of the Ca II K line calibrated in surface flux units for three dMe and 2 dM stars observed at quiescent times are constructed. The models reveal several systematic trends. Large values of the ratio of T(min) to T(eff) are derived, indicating a large amount of nonradiative heating present in the upper photospheres of M dwarf stars. It is also found that the lower chromospheric temperature gradient is similar for all the M dwarf stars. Since for the models here the chromospheric K line emission strength is most sensitive to the total amount of chromospheric material present within the approximate temperature range T(min)-6000 K, increasing the emission strength is not simply due to increasing chromospheric temperature gradients. It is also found that both the electron density and electron temperature at one thermalization length in the K line below the top of the chromospheres are greater in the dMe stars than in the dM stars. The M dwarf models here have microturbulent velocities between 1 and 2 km/sec, which are much smaller than for solar chromosphere models. Title: Speckle interferometric observations of Pluto and Charon Authors: Hege, E. K.; Hubbard, E. N.; Drummond, J. D.; Strittmatter, P. A.; Worden, S. P.; Lauer, T. Bibcode: 1982Icar...50...72H Altcode: We report speckle interferometric observations of Pluto and its moon (1978 P1) Charon obtained on 5 June 1980 with a single 1.8-m mirror of the Multiple Mirror Telescope. Our observations yield a separation of 0″.31 (±0″.05) between Pluto and Charon at position angle 285° (±7°) for JD 2444395.75. This result and other direct observations indicate an adjustment of +4.0 hr to the orbital epoch of R. S. Harrington and J. W. Christy [ Astron.J.86, 442-443 (1981)]. Our observation, which represents the first resolution of the system near minimum separation, also suggests that the inclination of the orbit to the plane of the sky should be increased by 3°; this will delay the onset of the predicted eclipsee season by one apparition to 1984 or 1985. Our data are consistent with Pluto diameter 0″.14 (±0″.02) = 3000 (±400) km and Charon diameter 0″..05 (±0″.03) = 1100 (±600) km. Title: Solar Rotation and Variability Observed in the Ca II K Line Authors: Keil, S. L.; Worden, S. P. Bibcode: 1982BAAS...14..623K Altcode: No abstract at ADS Title: High-speed photometry of the cepheid TT Aql. Authors: Connolly, L. P.; Africano, J. L.; Klimke, A.; Worden, S. P. Bibcode: 1982PASP...94..182C Altcode: High-speed differential photometry is presented for the classical Cepheid TT Aql. There is good coverage over most phases of the light curve. An irregularity in the light curve during the ascending branch stand-still is possibly identified. The period for this Cepheid is briefly discussed. Title: A heating mechanism for the chromospheres of M dwarf stars. Authors: Giampapa, M. S.; Golub, L.; Rosner, R.; Vaiana, G. S.; Linsky, J. L.; Worden, S. P. Bibcode: 1982SAOSR.392A..73G Altcode: 1982csss....2...73G The atmospheric structure of the dwarf M-stars which is especially important to the general field of stellar chromospheres and coronae was investigated. The M-dwarf stars constitute a class of objects for which the discrepancy between the predictions of the acoustic wave chromospheric/coronal heating hypothesis and the observations is most vivid. It is assumed that they represent a class of stars where alternative atmospheric heating mechanisms, presumably magnetically related, are most clearly manifested. Ascertainment of the validity of a hypothesis to account for the origin of the chromospheric and transition region line emission in M-dwarf stars is proposed. Title: An Air Force/NSF initiative to study the origins of solar activity. Authors: Worden, S. P.; Dunn, R. B.; Smith, M. A.; Zirker, J. B. Bibcode: 1982SAOSR.392B.221W Altcode: 1982csss....2..221W No abstract at ADS Title: Coordinated X-ray, optical and radio observations of flaring activityon YZ Canis Minoris. Authors: Kahler, S.; Golub, L.; Harnden, F. R.; Liller, W.; Seward, F.; Vaiana, G.; Lovell, B.; Davis, R. J.; Spencer, R. E.; Whitehouse, D. R.; Feldman, P. A.; Viner, M. R.; Leslie, B.; Kahn, S. M.; Mason, K. O.; Davis, M. M.; Crannell, C. J.; Hobbs, R. W.; Schneeberger, T. J.; Worden, S. P.; Schommer, R. A.; Vogt, S. S.; Pettersen, B. R.; Coleman, G. D.; Karpen, J. T.; Giampapa, M. S.; Hege, E. K.; Pazzani, V.; Rodono, M.; Romeo, G.; Chugainov, P. F. Bibcode: 1982ApJ...252..239K Altcode: The YZ Canis Minoris (Gliese 285), a late-type dwarf star with Balmer emission (dM4.5e), is a member of the UV Ceti class of flare stars. Obtaining good X-ray observations of a dMe star flare is important not only for understanding the physics of flares but also for testing current ideas regarding the similarity between stellar and solar flares. The Einstein X-ray Observatory has made it possible to conduct X-ray observations of dMe stars with unprecedented sensitivity. A description is presented of the results of a program of ground-based optical and radio observations of YZ CMi coordinated with those of the Einstein Observatory. The observations were carried out as part of a coordinated program on October 25, 26, and 27, 1979, when YZ CMi was on the dawn side of the earth. Comprehensive observational data were obtained of an event detected in all three wavelength regions on October 25, 1979. Title: Speckle interferometry with the Multiple Mirror Telescope. Authors: Hege, E. K.; McCarthy, D. D.; Strittmatter, P. A.; Worden, S. P.; Lowe, F. J. Bibcode: 1982JOSA...72.1759H Altcode: 1982OSAJ...72.1759H No abstract at ADS Title: A preflare diminution in the quiescent flux of EQ Pegasi. Authors: Giampapa, M. S.; Africano, J. L.; Klimke, A.; Parks, J.; Quigley, R. J.; Robinson, R. D.; Worden, S. P. Bibcode: 1982ApJ...252L..39G Altcode: The occurrence of a remarkable flare event on EQ Peg is reported as recorded by high speed photometry in the Johnson U band: a stellar flare event is immediately preceded by a well-defined decline in the quiescent flux of the star. The U band flux decays to a minimum level that is 75% of the stellar quiescent flux, and the duration of the so-called negative flare event is 2.7 minutes. A description of the observation is presented and hypotheses are discussed that may eventually account for this phenomenon. Title: The AFGL image reconstruction program 2 speckle interferometry Authors: Worden, S. P.; Hege, E. K.; Hubbard, E. N.; Woolf, N. J.; Strittmatter, P. A. Bibcode: 1981afhr.rept.....W Altcode: Recent work indicates that large-telescope, optics-limited images are recoverable for objects as faint as +15 stellar magnitudes using a technique called speckle interferometry. This report presents a review of speckle interferometry, including current status and results. Section 2 provides a background of the Fourier mathematics used in image processing and optical systems. Section 3 describes how the atmosphere degrades astronomical images and how speckle interferometry has been used to recover high-resolution detail. Section 4 describes new work to recover actual optics-limited images, and compares active optics systems with speckle interferometry. Title: Speckle interferometry observations of the triple QSO PG 1115+08. Authors: Hege, E. K.; Hubbard, E. N.; Strittmatter, P. A.; Worden, S. P. Bibcode: 1981ApJ...248L...1H Altcode: Speckle interferometric observations of the 16.2 mag component A of PG 1115 + 08 show that it is resolved into two components, separated by 0.54 arcsec in position angle 20 deg. The data suggest that the two components are approximately equally bright and are unresolved at a resolution of approximately 0.15 arcsec. These results are consistent with those inferred from long exposure images. Title: High-resolution profiles of chromospheric lines in M dwarf stars. Authors: Worden, S. P.; Schneeberger, T. J.; Giampapa, M. S. Bibcode: 1981ApJS...46..159W Altcode: Forty-six hydrogen and sodium line profiles are presented for 17 selected dwarf M and dwarf M emission line stars. These profiles, derived from echelle spectrograms, typically have 0.25 A spectral resolution. Most of the dMe stars show hydrogen emission lines with central reversals. Central emission features in the cores of the Na D lines are often observed, and the presence of these emission features is strongly correlated with hydrogen line emission. Title: Stellar model chromospheres. XII. High-resolution, absolute flux profiles of the CaII H and K lines in dMe and non-dMe stars. Authors: Giampapa, M. S.; Worden, S. P.; Schneeberger, T. J.; Cram, L. E. Bibcode: 1981ApJ...246..502G Altcode: We present 142 mÅ resolution spectra of the cores and wings of the Ca II H and K lines in three dMe and four comparison dwarf M stars, obtained with the KPNO 4 m echelle spectrograph and blue image tube. The narrow-band photometry of Willstrop and the Barnes and Evans relations for stellar angular diameters convert the observed relative flux to absolute surface flux units with an estimated uncertainty of ± 15 %. We derive chromospheric radiative loss rates in the H and K lines and discuss trends in these loss rates with effective temperature. Monochromatic surface fluxes are tabulated for different features in the H and K lines, and radiation temperatures are derived from the mean surface fluxes at K1 and H1, respectively. We find TR(H1) > TR(K1), consistent with partial redistribution theory. The TR(K1)/Teff ratio is higher in these M dwarfs than the giants studied in Paper X, and it is anomalously high for the dMe flare star YZ CMi. If TR(K1)/Teff is an empirical age indicator, then the result for YZ CMi implies that flare activity and youth are directly correlated, as has been suggested by other investigators. Moreover, the result implies that a high degree of nonradiative heating is present in the upper photospheres of dMe stars. Measurements of line widths at H1 and K1 are presented together with FWHM data for the H and K lines. We find that the scaling law proposed by Ayres generally agrees with the observed trend exhibited by the K1 widths. We also discuss chromospheric radiative loss rates in the Hɛ line compared with loss rates in the H and K lines, and present corrected FWHM(K) widths and compare them to the widths predicted by the Wilson-Bappu relation as calibrated by Lutz. Title: Possible radio flaring activity on a late-type giant star, alf Cet. Authors: Boice, D. C.; Kuhn, J. R.; Robinson, R. D.; Worden, S. P. Bibcode: 1981ApJ...245L..71B Altcode: A search is made for radio flare events on 15 late-type stars using the Arecibo radio telescope at 430 MHz. About 50 hr of interference-free data are obtained and one impulsive event is detected for the M2 III star Alpha Cet. The observed radio event is consistent with the hypothesis that it originated in a solar-flare-type disturbance in the stellar atmosphere. Title: Flare activity on T Tau stars. Authors: Worden, S. P.; Schneeberger, T. J.; Kuhn, J. R.; Africano, J. L. Bibcode: 1981ApJ...244..520W Altcode: Observations of short-period photometric fluctuations in T Tauri stars show flarelike events. These events are consistent with the superposition of many solar-like flare events and have a power-spectrum frequency dependence of ∼f-2. This dependence is the same as that observed on UV Ceti stars. The flare events are very powerful, and the expected proton flux from these events may explain early solar system abundance anomalies without recourse to nearby supernovae. The flare events are consistent with the observations of mass loss in these stars. Title: Recent Interferometric Results Authors: Worden, S. Bibcode: 1981siwn.conf..443W Altcode: No abstract at ADS Title: The Photometric Variability of Main Sequence Stars Authors: Radick, R. R.; Hartmann, L. W.; Mihalas, D. M.; Worden, S. P. Bibcode: 1981BAAS...13R.832R Altcode: No abstract at ADS Title: Recent Results in Observing Solar Phenomena in Stars Authors: Worden, S. Bibcode: 1981siwn.conf..201W Altcode: No abstract at ADS Title: Detecting Planets in Binary Systems with Speckle Interferometry Authors: Worden, S. P. Bibcode: 1981NASCP2156..177W Altcode: 1981litu.conf..177W The potential of speckle interferometry in the astrometric detection of stellar motions due to the presence of planetary bodies in binary star systems is discussed. Sources of atmospheric image degradation are considered, and the principles of speckle interferometry, which acts to eliminate atmospheric effects by the correlation of short-exposure photographs, are outlined. Instruments used in speckle interferometry are discussed, and data reduction techniques, involving Fourier transformations and the removal of residual seeing effects, are indicated. Experience in the speckle interferometry of binary systems is presented which has shown errors due to uncertainty in the data to be + or - 0.3% in separation and + or - 0.2 deg in position angle for each 50-frame data set. A set of possible binary star systems to be included in a search for planetary systems is examined, and it is shown that about half of these nearby systems should have stable orbits for a Jovian planet, which should be detectable within the accuracies possible for speckle interferometry. Title: The Mg II h and k lines in a sample of dMe and dM stars. Authors: Giampapa, M. S.; Pornmann, P. L.; Ayres, T. R.; Linsky, J. L.; Worden, S. P. Bibcode: 1981NASCP2171..279G Altcode: 1981uviu.nasa..279G; 1981NASCP3171..279G; 1980IUE80......279G Both Mg II h and k line fluxes are presented for a sample of 4 dMe and 3 dM stars obtained with the IUE satellite in the long wavelength, low dispersion mode. The observed fluxes are converted to stellar surface flux units and the importance of chromospheric non radiative heating in this sample of M dwarf stars is intercompared. In addition, the net chromospheric radiative losses due to the Ca II H and K lines in those stars in the sample for which calibrated Ca II H and K line data exist are compared. Active region filling factors which likely give rise to the observed optical and ultraviolet chromospheric emission are estimated. The implications of the results for homogeneous, single component stellar model chromospheres analyses are discussed. Title: An image reconstruction for Capella with the Steward Observatoty. Authors: Cocke, W. J.; Hege, E. K.; Hubbard, E. N.; Strittmatter, P. A.; Worden, S. P. Bibcode: 1983LowOB...9..159C Altcode: 1983LowOB.167..159C; 1981LowOB...9..159C; 1983IAUCo..62..159C Since their invention in 1970, speckle interferometric techniques have evolved from simple optical processing of photographic images to high-speed digital processing of quantum-limited video data. Basic speckle interferometric techniques are discussed, taking into account the implementation of two distinct data-recording/data-processing modes. A description of image reconstruction techniques is also provided. Two methods for image phase retrieval have been implemented, including a phase unwrapping method developed by Cocke (1980) and the phase accumulation method of Knox and Thompson (1974). On February 3, 1981, analogue mode speckle interferograms for Capella and the unresolved star Gamma Ori were obtained with both the phase-unwrapping and the Knox-Thompson method. Title: UV chromospheric and circumstellar diagnostic features among F supergiant stars. Authors: Stencel, R. E.; Worden, S. P.; Giampapa, M. S. Bibcode: 1981NASCP2171..311S Altcode: 1981NASCP3171..311S; 1980IUE80......311S; 1981uviu.nasa..311S A survey of F supergiant stars to evaluate the extension of chromospheric and circumstellar characteristics commonly observed in the slightly cooler G, K, and M supergiant is discussed. An ultraviolet survey was elected since UV features of Mg II and Fe II might persist in revealing outer atmosphere phenomena even among F supergiants. The encompassed spectral types F0 to G0, and luminosity classes Ib, Ia, and Ia-0. In addition, the usefulness of the emission line width-to-luminosity correlation for the G-M stars in both the Ca II and Mg II lines is examined. Title: Recovery of intensity information from speckle data. Authors: Hege, E. K.; Hubbard, E. N.; Cocke, W. J.; Strittmatter, P. A.; Worden, S. P.; Radick, R. R. Bibcode: 1983LowOB...9..185H Altcode: 1983IAUCo..62..185H; 1981LowOB...9..185H; 1983LowOB.167..185H The present investigation is concerned with effects of instrumental response and photon statistics, the so-called noise bias, and procedures for correcting these effects in order to recover binary star relative intensity information from speckle interferometric data. The intensity retrieval problem is considered along with details regarding the noise bias problem, complications which ultimately limit the accuracy with which binary star intensity ratios may be determined, and some preliminary results. Attention is given to calibration uncertainties, position angle uncertainties, the observing band-pass, and the major contributions to magnitude difference uncertainties. Title: The angular diameters of supergiant stars from speckle interferometry. Authors: Welter, G. L.; Worden, S. P. Bibcode: 1980ApJ...242..673W Altcode: The Lynds et al (1976) image reconstruction algorithm is applied to speckle interferometric data for the supergiant stars alpha Ori, alpha Cet, alpha Tau, rho Per, and alpha Her. Further restoration is applied to the images of alpha Ori and omicron Cet. Estimations of angular diameter as a function of wavelength and limb darkening are made, confirming the observation by Bonneau and Labeyrie (1973) that such stars appear smaller at long wavelengths. An upper limit is placed on the degree of large-scale surface structure on alpha Ori. Title: The outher atmospheres of cool stars. VII. High resolution, absolute flux profiles of the MG II H and K lines in stars of spectral types F8 to M5. Authors: Stencel, R. E.; Mullan, D. J.; Linsky, J. L.; Basri, G. S.; Worden, S. P. Bibcode: 1980ApJS...44..383S Altcode: We present high-resolution lUE spectra of the emission cores of the Mg II resonance doublet at 280 nm in a selection of 54 stars covering a range of spectral type from F8 to MS and of luminosity class from supergiant (Ia) to subgiant (IV). These spectra were obtained with the LWR echelle system onboard the IUE satellite, and have been calibrated in absolute flux units using OAO 2 photometry of Eta UMa as a standard, plus the Barnes and Evans relations for stellar angular diameters. The uncertainty in flux is probably of order 20%. We discuss the qualitative line profile groupings, as determined by Basri and Linsky, and derive chromospheric radiative losses in the h and k lines; we discuss these loss rates as functions of effective temperature and luminosity class. We make further comparisons of these rates with rates derived for the Ca II H and K lines by Linsky and his colleagues. Chromospheric velocity fields and indicators of circumstellar envelopes are discussed in terms of profile asymmetries and other diagnostics. Line width measures and velocity shifts of the central reversals are tabulated, among other quantities, and several correlations noted. Finally, we discuss the relation of the Wilson K index and stellar coronae to Mg II emission, and note the occurrence of Fe II emission lines in the middle range of the UV of late-type stars. Title: The Chromospheres of M Dwarf Stars Authors: Giampapa, M. S.; Worden, S. P.; Linsky, J. L. Bibcode: 1980BAAS...12..807G Altcode: No abstract at ADS Title: High Speed Photometry of Stepanian's Star Authors: Worden, S. P.; Eason, E. L. E.; Africano, J.; Klimke, A. Bibcode: 1980BAAS...12..851W Altcode: No abstract at ADS Title: Photometric Observations of Active Chromosphere Stars Authors: Wilkerson, M. S.; Rogers, W.; Ruden, S.; Africano, J. L.; Klimke, A.; Worden, S. P. Bibcode: 1980BAAS...12Q.807W Altcode: No abstract at ADS Title: Status of Cloudcroft Solar Variability Program Authors: Worden, S. P.; Eason, E.; Africano, J.; Klimke, A.; Radick, R.; Wilkerson, M. S. Bibcode: 1980BAAS...12..897W Altcode: No abstract at ADS Title: Speckle Interferometric Observations of Pallas Authors: Hege, E. K.; Cocke, W. J.; Hubbard, E.; Gresham, M.; Strittmatter, P. A.; Worden, S. P.; Radick, R. Bibcode: 1980BAAS...12R.509H Altcode: No abstract at ADS Title: Large Scale Solar Velocity Features Authors: Kuhn, J. R.; Worden, S. P. Bibcode: 1980BAAS...12..473K Altcode: No abstract at ADS Title: The diameter of chi Cygni by speckle interferometry. Authors: Christou, J.; Worden, S. P. Bibcode: 1980AJ.....85..302C Altcode: The technique of speckle interferometry is applied to Chi Cygni, a Mira-type variable, giving a mean diameter of (23.08 plus or minus 4.08) x 10 to the -3rd arcsec. Two methods of data reduction were applied giving good agreement with each other. The result tends to support the conclusion of Labeyrie et al. (1977) that Mira stars have radii R not greater than 18 solar radii as opposed to the previously assumed value of R 320 solar radii. Title: Observations of magnetic fields on two late-type dwarf stars. Authors: Robinson, R. D.; Worden, S. P.; Harvey, J. W. Bibcode: 1980ApJ...236L.155R Altcode: The detection of magnetic fields on the G8 V star Xi Boo A and on the K0 B star 70 Oph A is reported. A method has been developed and applied which provides estimates of the total field strength and fraction of the visible stellar surface covered by fields. The essence of this method is to perform the Fourier deconvolution of a nonmagnetically sensitive line profile from a magnetically sensitive one. This method is insensitive to magnetic field geometry and does not depend on polarization measurements. Results indicate fields of 2550 + or 390 gauss covering 20-45% Xi Boo A, and that fields of 1880 + or - 350 gauss may cover 10% of 70 Oph A. Comparison observations of solar active regions show fields of 1800 + or - 550 gauss covering 10% of the solar active regions, in line with previous work. Tests of solar quiet regions and sunspots also support the validity of the stellar measurements. Title: Observational Astronomy at the Cloudcroft Observatory Authors: Schneeberger, Timothy J.; Worden, S. P. Bibcode: 1980srca.conf...67S Altcode: No abstract at ADS Title: Sources of noise in solar limb definitions Authors: Keil, S. L.; Worden, S. P. Bibcode: 1980LNP...125..219K Altcode: 1980nnsp.work..219K A test series of spectroheliograms has been used to evaluate the hypothesis that the rotation and evolution of solar surface structure can function as a source of noise in solar limb definition measurements. The study confirms the hypothesis, and results demonstrate the amount of variation in solar limb position which is attributable to evolutionary changes in solar surface structure. Title: Cloudcroft Observatory Today Authors: Schneeberger, Timothy J.; Worden, S. P.; Africano, J. L.; Tyson, E. Bibcode: 1980S&T....59..109S Altcode: No abstract at ADS Title: High angular resolution astronomical techniques. Speckle interferometry and related methods. Authors: Worden, S. P. Bibcode: 1980SPIE..243...66W Altcode: A review of speckle interferometry techniques and hardware for recovering image information degraded by turbulence (which reduces angular resolution to about 1 arcsec) in the earth's atmosphere is presented. Speckle interferometry, which relies on post processing of short exposure images, provides two orders of magnitude increase in angular resolution for studying object sizes and binary star orbits. Lynds et al. (1976) showed that images of bright stars were directly obtainable from speckle photos. For more general image reconstruction, the power spectrum used to determine angular sizes must be supplemented with Fourier phases. Knox and Thompson (1974) developed statistical techniques to get the phase from speckle photos directly; however, the techniques are highly noise sensitive and limited to bright objects like the sun. A method developed by Fienup (1978) was applied to derive phases for faint astronomical targets. The method is insensitive to noise and shows that actual diffraction-limited images can be reconstructed for objects fainter than +15 magnitudes. Title: New Photometric Observations of EX Hydrae Authors: Africano, J. L.; Quigley, R.; Schneeberger, T. J.; Worden, S. P. Bibcode: 1979BAAS...11..649A Altcode: No abstract at ADS Title: Detection of Magnetic Fields on Late-type Stars Authors: Robinson, R. D.; Boice, D.; Worden, S. P. Bibcode: 1979BAAS...11..648R Altcode: No abstract at ADS Title: Flare Activity on T Tauri Stars Authors: Schneeberger, T. J.; Worden, S. P.; Kuhn, F. R.; Africano, J. L. Bibcode: 1979BAAS...11..628S Altcode: No abstract at ADS Title: High Resolution Spectra of Stellar Flares Authors: Worden, S. P.; Schneeberger, T. J.; Deluca, E.; Giampapa, M. Bibcode: 1979BAAS...11..628W Altcode: No abstract at ADS Title: The Ca II H and K Lines in dMe and non-dMe Stars Authors: Giampapa, M. S.; Worden, S. P.; Schneeberger, T. J.; Cram, L. E. Bibcode: 1979BAAS...11..625G Altcode: No abstract at ADS Title: High-resolution line profiles of T Tau stars. Authors: Schneeberger, T. J.; Worden, S. P.; Wilkerson, M. S. Bibcode: 1979ApJS...41..369S Altcode: Thirty-three relative intensity hydrogen and sodium line profiles obtained from spectra of 10 T Tauri stars are presented. These profiles were derived from echelle spectrograms having a typical resolution of 0.20 A. The T Tauri stars observed span the range of emission-intensity classes listed in Herbig and Rao (1972). Seventy percent of the H alpha profiles show blue-displaced absorption components with velocities up to 250 km/sec. Na D emission features are observed in all the stars with emission-intensity classes higher than 2. The Na D lines in T Tauri show intensity changes on a time scale of months. The H alpha-line equivalent width in T Tauri can change by 40% in 3 days. Title: Stellar model chromospheres. X. High-resolution, absolute flux profiles of the Ca II H and K lines in stars of spectral types F0 - M2. Authors: Linsky, J. L.; Worden, S. P.; McClintock, W.; Robertson, R. M. Bibcode: 1979ApJS...41...47L Altcode: We present 120 mÅ resolution spectra of the cores and wings of the Ca II H and K lines in 43 stars covering a wide range of spectral type and luminosity class. These spectra were obtained with the KPNO 4 m echelle spectrograph and blue image tube, and are calibrated in absolute surface flux units using Willstrop's narrow-band photometry and the Barnes and Evans relations for stellar angular diameters. We estimate an uncertainty of ±15% in our flux scales. We derive chromospheric radiative loss rates in the H and K lines, and discuss trends in these loss rates with effective temperature for dwarfs, giants, and supergiants. We compare these loss rates with similar rates for the Mg II h and k lines, and discuss the doublet line ratios for H and K. The monochromatic surface fluxes for different features in the H and K lines are presented. From the surface fluxes at K1 we derive the radiation temperature TR(K1). The TR(K1)/Teff ratio is lower in giants than in dwarfs, as predicted by partial redistribution calculations, and this ratio appears to be an empirical age indicator among dwarfs. Asymmetries in the K line profile provide evidence for a solar-type supergranulation flow pattern in F5-K5 dwarfs and perhaps also in G and early K supergiants. Measurements of line widths at H1, K1, and K2 are presented, together with FWHM data for the H and K lines. We find rough agreement between the measured K1 widths and the gravity and chromospheric heating rate dependences in the scaling law proposed by Ayres. Finally, we present data on emission lines in the wings of H and K, and discuss chromospheric radiative loss rates in the HE line compared with loss rates in the H and K lines. Title: Speckle interferometery. I. The Steward Observatory. Authors: Hubbard, G.; Hege, K.; Reed, M. A.; Strittmatter, P. A.; Woolf, N. J.; Worden, S. P. Bibcode: 1979AJ.....84.1437H Altcode: The Steward Observatory speckle camera is described. The optical system images light onto a four stage image tube which is then lens-coupled to either a photographic camera or to a CID camera. The device has been used in its photographic mode to study the extent of the isoplanatic patch at the 2.3 m telescope. With 20 ms exposures, the correlation between the speckle patterns of close binary systems has essentially disappeared for separations exceeding 6 arcsec. Title: The lifetimes of sunspot moats. Authors: Pardon, L.; Worden, S. P.; Schneeberger, T. J. Bibcode: 1979SoPh...63..247P Altcode: Daily full disk magnetograms observed with the Kitt Peak 40 channel magnetograph have been examined for the rise time, decay time and lifetime of sunspot moats. Eighteen well defined moats result in rise and decay times of 0.5d ± 1d, with a lifetime at maximum development of 6d ± 3d. The moat appears approximately 3 days after the spot is observed in our data. Title: The night sky conditions at the Sacramento Peak Observatory. I. Sky brightness. Authors: Schneeberger, T. J.; Worden, S. P.; Beckers, J. M. Bibcode: 1979PASP...91..530S Altcode: The night sky brightness at Sacramento Peak Observatory has been monitored over a period of nine months. The average zenith sky is 21.9 ± 0.1 mυ arc sec-2. The night sky brightness shows fluctuations of up to 25% during this period. The long record of daytime sky-brightness observations shows a strong seasonal effect with brightest skies occurring in the early summer months. This seasonal effect is marginally present in the night sky brightness results. Light pollution from the closest urban areas is also detailed. Title: Chromospheric emission lines in the red spectrum of AD Leonis. II. Physical conditions in flares. Authors: Schneeberger, T. J.; Linsky, J. L.; McClintock, W.; Worden, S. P. Bibcode: 1979ApJ...231..148S Altcode: Simultaneous photometry and time-resolved spectra of the dMe flare star AD Leo has been used to deduce flare temperatures, electron densities, and dimensions. Photometric results for two qualitatively different flares yield estimates of the differences in physical properties between these flares. Flares on AD Leo are hotter and denser than their solar counterparts, and spike-like flares occupy smaller volumes than longer-lived flares. An upper limit to the flare X-ray luminosity is set atL <4 x l028ergss-1. Subject headings: stars: chromospheres - stars: emission-line - stars: flare - stars: individual Title: The effect of chromospheric activity on metallicity measurements. Authors: Giampapa, M. S.; Gilliam, L. B.; Worden, S. P. Bibcode: 1979ApJ...229.1143G Altcode: The intermediate band uvby-beta photometric system is used to observe solar active (plage) regions and quiescent regions in an effort to determine the effect of chromospheric activity on photometric metallicity measurements. It is found that the active regions appear metal deficient with respect to the quiet sun by approximately 35%. Title: Short Time Scale Brightness Fluctuations in BP Tauri Authors: Schneeberger, T. J.; Worden, S. P.; Africano, J. L. Bibcode: 1979IBVS.1582....1S Altcode: No abstract at ADS Title: Stellar model chromospheres. IX. Chromospheric activity in dwarf stars. Authors: Kelch, W. L.; Linsky, J. L.; Worden, S. P. Bibcode: 1979ApJ...229..700K Altcode: High-resolution Ca II K line profiles are used to model the upper photospheres and lower chromospheres of eight main-sequence stars ranging in spectral type from F0 to M0 and exhibiting different degrees of chromospheric activity. The model chromospheres are studied as a function of spectral type and activity for stars of similar spectral type in order to obtain evidence of enhanced nonradiative heating in the upper-photospheric models and in the ratio of minimum temperature at the base of the chromosphere to effective temperature, a correlation between activity and temperature in the lower chromospheres, and a correlation of the width at the base of the K-line emission core and at the K2 features with activity. Chromospheric radiative losses are estimated for the modelled stars and other previously analyzed main-sequence stars. The results obtained strengthen the argument that dMe flare stars exhibit fundamentally solar-type activity but on an increased scale. Title: Simultaneous X-ray, UV, Optical, and Radio Observations of the Flare Star Proxima Centauri Authors: Haisch, B. M.; Linsky, J. L.; Slee, O. B.; Worden, S. P. Bibcode: 1979BAAS...11..471H Altcode: No abstract at ADS Title: Short Time Scale Brightness Fluctuations in T Tauri Stars. Authors: Schneeberger, T. J.; Worden, S. P.; Africano, J. L. Bibcode: 1979BAAS...11..439S Altcode: No abstract at ADS Title: Evidence of long-period velocity fluctuations. Authors: Kuhn, J. R.; Worden, S. P. Bibcode: 1979ApJ...228L.119K Altcode: Evidence of a solar fluctuation with a period of 17 days is observed in spectroscopic differential-rotation data by using a technique developed to look at long time sequences of unevenly spaced data. Both spectroscopic observations and sunspot drift-velocity measurements indicate a possible periodicity between 184 and 364 days. The sunspot data marginally show fluctuations with periods which are multiples of 4.2 days. Title: Period Variation of UX Ursae Majoris in 1979 Authors: Quigley, R.; Africano, J. L.; Schneeberger, T. J.; Worden, S. P. Bibcode: 1979BAAS...11..445Q Altcode: No abstract at ADS Title: Sources of Noise in Solar Limb Definitions. Authors: Worden, S. P.; Keil, S. L. Bibcode: 1979BAAS...11..399W Altcode: No abstract at ADS Title: Photometric Eclipse Timings of RW TRIANGULI Authors: Africano, J. L.; Quigley, R.; Scheeberger, T. J.; Worden, S. P. Bibcode: 1979BAAS...11..433A Altcode: No abstract at ADS Title: AH Cancri: a contact binary in M67. Authors: Whelan, J. A. J.; Worden, S. P.; Rucinski, S. M.; Romanishin, W. Bibcode: 1979MNRAS.186..729W Altcode: The W UMa-type contact binary system AH Cnc, which is a member of the old galactic cluster M67, has been studied spectroscopically and photometrically. Estimates of masses, radii, effective temperature and luminosity of AH Cnc have been derived from these data and from cluster membership considerations. The results suggest that AH Cnc is a typical evolved W-type W UMa contact system, although whether the system has evolved as a contact system or has recently become so, could not be determined. The properties of AH Cnc are similar to those of TX Cnc in Praesepe. Information provided by the existence of a gap in the Hertzsprung-Russell diagram for M67 has been coupled with the AH Cnc results to provide further estimates of the chemical composition of M67. Title: Nucleosynthesis of 7Li in flares on UV Ceti stars. Authors: Karpen, J. T.; Worden, S. P. Bibcode: 1979A&A....71...92K Altcode: The possible production of Li-7 by nuclear reactions in UV Ceti flares has been considered. By utilizing solar observations and theory, a relationship is derived between flare energy and production rates for Li-7; approximately 100 erg of total flare energy is found to denote the formation of a Li-7 atom. Based on this value and best estimates of UV Ceti-type flare rates, it is concluded that less than 10% of the Li-7 observed in the intestellar medium may have been produced by this mechanism. Formation of significant amounts of interstellar deuterium by this method is ruled out. Title: A Contact Binary in M67 Authors: Whelan, J. A. J.; Worden, S. P.; Rucinski, S. M.; Romanishin, W. Bibcode: 1979NZJS...22..449W Altcode: No abstract at ADS Title: Angular diameter of the asteroids Vesta and Pallas determined from speckle observations. Authors: Worden, S. P.; Stein, M. K. Bibcode: 1979AJ.....84..140W Altcode: The technique of speckle interferometric measurement of asteroids is applied to Vesta and Pallas, yielding diameters of 550 i 23 and 673+55 km, respectively. The improved Vesta speckle diameter is in excellent agreement with other measurements for Vesta. However, the derived Pallas diameter is slightly larger than other measurements. This is perhaps attributable to systematic errors arising as an object's angular diameter nears the seeing disk size. It is also pointed out that it is necessary to carefully normalize and center speckle frames before applying the autocorrelation ,cross-correlation subtraction method developed by Worden et al. [Icarus 32, 450 (1977)]. Title: Interferometric determinations of asteroid diameters. Authors: Worden, S. P. Bibcode: 1979aste.book..119W Altcode: New interferometric techniques are discussed with reference to asteroid studies. Speckle interferometry makes it possible to recover some information down to large telescope diffraction limits. A multiple-aperture amplitude interfermeter system allows the full telescope aperture to be covered simultaneously and all Fourier components sampled simultaneously. The new techniques make it possible to directly determine diameters of asteroids from earth-based observations. Results for some solar system objects are given. New possibilities include image reconstruction for asteroids and the detection of close asteroid pairs. Title: The Cloudcroft Observatory 48 inch telescope. Authors: Africano, J. L.; Schneeberger, T. J.; Worden, S. P. Bibcode: 1979BAAS...11..392A Altcode: No abstract at ADS Title: Digital speckle interferometry to measure the angular diameters of faint objects Authors: Hubbard, G.; Reed, M.; Strittmatter, P.; Hege, K.; Worden, S. P. Bibcode: 1979hars.proc...28H Altcode: 1979IAUCo..50...28H A digital speckle camera for use on a 90-inch telescope has been developed. This camera uses a CID detector to provide photon locations in an image, or an analog image for brighter objects. This system has been used to observe Saturn's satellites Rhea and Iapetus. A correlation speckle technique is used to determine angular diameters of 1487 + or - 40 km for Rhea and 1200 + or - 132 km for Iapetus. Title: MG II and FE II Resonance Line Studies in Extremely Luminous F Stars Authors: Worden, Simon P. Bibcode: 1979iue..prop..266W Altcode: No abstract at ADS Title: Chromospheric emission lines in the red spectrum of AD Leonis. I. The nonflare spectrum. Authors: Giampapa, M. S.; Linsky, J. L.; Schneeberger, T. J.; Worden, S. P. Bibcode: 1978ApJ...226..144G Altcode: High-resolution red (5300-7300 A) spectra of the flare star AD Leonis were obtained with the Kitt Peak 4 m echelle spectrograph system at a spectral resolution of 0.22 A at Ha. A series of time-trailed plates with 5 hours integration in total were averaged together to obtain a representation of the star's nonflaring spectrum with high signal-to-noise ratio. The He i A5876 triplet line and A6678 singlet line appear in emission with measured equivalent widths of 0.312 + 0.016 A and 0.058 + 0.029 A, respectively. The corresponding triplet-to-singlet line flux ratio is 3.7, close to the ratio of the level statistical weights. We argue that the He i lines are not produced by recombination and cascade following photoionization by A < 504 A coronal photons, but are instead collisionally excited. We suggest that these lines are formed in a geometrically thin chromospheric layer at 20,000-50,000 K with a column density of nel 6 x 1018 . The sodium D emission lines (A5890, AS 896) are found to be stellar in origin, with measured FWHM of 0.7 A for both lines, and the Ha line has a FWHM of 1.4 A. No other chromospheric emission lines were found in this spectral region. Subject headings: stars: chromospheres - stars: emission-line - stars: flare - stars: individual Title: Image Reconstruction Using Speckle Interferometry Authors: Worden, S. P. Bibcode: 1978BAAS...10..630W Altcode: No abstract at ADS Title: On Egregious Theories-The Tunguska Event Authors: Wilkerson, M. S.; Worden, S. P. Bibcode: 1978QJRAS..19..282W Altcode: No abstract at ADS Title: Evidence of Long Period Solar Velocity Fluctuations Authors: Kuhn, J. R.; Worden, S. P. Bibcode: 1978BAAS...10..639K Altcode: No abstract at ADS Title: A study of the contact binary system ER Cephei. Authors: Worden, S. P.; Coleman, G. D.; Rucinski, S. M.; Whelan, J. A. J. Bibcode: 1978MNRAS.184...33W Altcode: Summary. Photoelectric V and B light curves of ER Cephei, a 1 6-mag W Ursae Majoris-type binary system in NGC 188, are described. The available data are not sufficient definitely to determine whether the light curve of the system is of A type or W type, although this analysis suggests the latter. Light-curve synthesis solutions are calculated for both cases, together with their uncertainties. The results show that ER Cep is similar to field contact binaries, is in marginal contact, has a well-determined inclination angle, i = 79 j 30, and has a poorly determined mass ratio, q = 0.55 +0.20. A brief discussion is given of system parameters for ER Cep derived from cluster membership considerations. The need for spectroscopic data and the importance of ER Cep for cluster Hertzsprung-Russell diagram gap theory is stressed. Title: Speckle interferometry. Authors: Worden, S. Bibcode: 1978NewSc..78..238W Altcode: It is noted that atmospheric twinkling (or 'seeing') limits the resolution obtainable from ground-based telescopes. The limit of angular resolution is inversely proportional to the diameter of the main light collector. Turbulence in the earth's atmosphere degrades this angular resolution. In order to rectify this problem, multiple-aperture interferometers, consisting of a large number of images superimposed on each other, have been used. These 'speckled' images may be analyzed with Fourier mathematics and Fourier processing. The methods have been used for studying binary stars and for determining the sizes of asteroids and the sun. A technique has also been developed for reconstructing actual images of Betelgeuse, the red star in the shoulder of the Orion constellation. It is based on computer processing data on individual speckles in a series of images. In the future speckle size determinations will be extended to quasars and exploding galactic nuclei. Title: Speckle Interferometry at Steward Observatory. Authors: Hubbard, E.; Strittmatter, P. A.; Woolf, N. J.; Hege, K.; Worden, S. P. Bibcode: 1978BAAS...10..459H Altcode: No abstract at ADS Title: The Effects of Stellar Chromospheric Activity on Metallicity Measurements. Authors: Giampapa, M. S.; Worden, S. P. Bibcode: 1978BAAS...10..458G Altcode: No abstract at ADS Title: Equivalence principle tests in Earth orbit. Authors: Worden, P. W., Jr. Bibcode: 1978AcAau...5...27W Altcode: An analysis of experiments which test the uniqueness of the ratio of inertial and passive gravitational mass has been made. The analysis shows that an improvement in sensitivity of at least six orders of magnitude is possible in Earth orbit. The optimum experiment compares the rate of fall of two independent test bodies in a cryogenic environment aboard a drag-free satellite; this "free fall" experiment is very much less sensitive to gravity gradient than is a torsion balance. The dominant noise sources for such an experiment are expected to be gravity gradients, tracking errors, and gas pressure effects; thermal noise is not a limiting factor. A laboratory version of the experiment is under test; preliminary results are described. Title: The helium triplet-to-singlet ratio in T Tauri stars. Authors: Schneeberger, T. J.; Linsky, J. L.; Worden, S. P. Bibcode: 1978A&A....62..447S Altcode: Summary. The He ilines at 5876 and 6678 are used to determine the triplet-to-singlet ratio for T Tauri stars DF Tau and BP Tau. The ratio is approximately 3. Line profiles and absolute intensities are presented. Key words: T Tauri stars helium lines Title: Speckle Interferometry Authors: Worden, S. P. Bibcode: 1978NewSc...4..238W Altcode: No abstract at ADS Title: A Method for Processing Stellar Speckle Interferometry Data Authors: Welter, G. L.; Worden, S. P. Bibcode: 1978JOSA...68.1271W Altcode: 1978OSAJ...68.1271W No abstract at ADS Title: The Angular Diameter of Vesta from Speckle Interferometry Authors: Worden, S. P.; Stein, M. K.; Schmidt, G. D.; Angel, J. R. P. Bibcode: 1977Icar...32..450W Altcode: It is shown that the autocorrelation function of a telescope diffraction-limited image is closely approximated by a subtraction of the mean cross correlation of pairs of speckle photographs from the mean autocorrelation of the same set of data. This fact is used to derive the angular diameter of the asteroid Vesta from a series of speckle interferometry data. The resultant apparent angular diameter of 0″.40 ± 0″.04 corresponds to an absolute diameter of 513 ± 51 km. Title: Large-scale winds driven by flare-star mass loss. Authors: Coleman, G. D.; Worden, S. P. Bibcode: 1977ApJ...218..792C Altcode: The effect of injecting substantial quantities of high-temperature material into the interstellar medium from flare-star activity is examined. Using models like those developed by Mathews and Baker for calculating supernovae-driven elliptical galaxy winds, we consider the effects of flare-star mass loss in elliptical galaxies and globular clusters. It is found that, even in the absence of supernovae, and with a substantially smaller flare-star mass input than may be plausibly expected, steady outflowing winds will develop in these objects. Such winds may explain the observed absence of substantial quantities of interstellar material in globular clusters and elliptical galaxies. Assuming the presence of elliptical galaxy winds in clusters of galaxies, we consider the effects of such winds on intergalactic medium dynamics. We find that a hot intergalactic medium is to be expected and that instabilities resulting in collapse in the center of clusters of galaxies may occur. Title: Spectroscopic orbit of CC Comae. Authors: Rucinski, S. M.; Whelan, J. A. J.; Worden, S. P. Bibcode: 1977PASP...89..684R Altcode: Radial velocity measurements of CC Corn, the shortest period W UMa-type system, are resented. The results are combined with photometric results to provide an estimate of the absolute elements. The system has total luminosity 0.29 :1: 0.03 Lu and masses of 0.69 :1: 0.06 , and 0.36 :1: 0.03 @. Formal errors are quoted here, and the possibility of much larger systematic errors is discussed in the text. The value of the mass ratio derived spectroscopically (0.52 :1: 0.03) conflrrns the value derived from photometry. The distance to CC Corn (83 :1: 4 pc) is discussed with reference to membership of the Coma cluster (Mel 111). The importance of CC Corn for theoretical models of contact binary systems is stressed. Key words: stars: individual-spectroscopic elements-contact binaries Title: Chromospheric Emission Lines in the Quiescent Spectrum of the Flare Star AD Leo Authors: Giampapa, M. S.; Linsky, J. L.; Schneeberger, T. J.; Worden, S. P. Bibcode: 1977BAAS....9..593G Altcode: No abstract at ADS Title: Modeling of Chromospheric Activity in F-M Dwarf Stars and the Sun. Authors: Kelch, W. L.; Linsky, J. L.; Worden, S. P. Bibcode: 1977BAAS....9..651K Altcode: No abstract at ADS Title: Image restoration techniques applied to QSO images. Authors: Wehinger, P. A.; Worden, S. P.; Wyckoff, S. Bibcode: 1977BAAS....9..608W Altcode: No abstract at ADS Title: Image Restoration Techniques Applied to QSO Images Authors: Wehinger, P. A.; Worden, S. P.; Wyckoff, S. Bibcode: 1977BAAS....9Q.608W Altcode: No abstract at ADS Title: Simultaneous Photometry and Time Resolved Spectra of Flare Star AD Leo Authors: Schneeberger, T. J.; Worden, S. P.; Linsky, J. L.; McClintock, W. Bibcode: 1977BAAS....9Q.593S Altcode: No abstract at ADS Title: Further speckle interferometric studies of alpha Orionis. Authors: Wilkerson, M. S.; Worden, S. P. Bibcode: 1977AJ.....82..642W Altcode: No abstract at ADS Title: INVITED PAPER - Solar and Stellar Speckle Interferometry. Authors: Worden, S. P. Bibcode: 1977BAAS....9R.374W Altcode: No abstract at ADS Title: On the Origin of Oscillations in the Solar Limb Position. Authors: Worden, S. P.; Simon, G. W. Bibcode: 1977BAAS....9..358W Altcode: No abstract at ADS Title: Astronomical image reconstruction Authors: Worden, S. P. Bibcode: 1977VA.....20..301W Altcode: Atmospheric turbulence limits angular resolution of earth-based telescopes to about one arc-second. A technique, speckle interferometry, has been developed which uses very short exposure photographs to obtain information approaching the limit of telescope angular resolution permitted by the Rayleigh limit. Procedures for reconstructing images free from atmospheric smearing by means of speckle interferometry and related methods are discussed. Different approaches include: direct Fourier deconvolution, considering speckles as images, generalized image reconstruction, and active systems which require no post-detection processing (for example, a system using a mirror with a deformable surface, known as the 'rubber mirror'). Photographic speckle apparatus is described and the limitations of the procedure are examined. Title: Direct observations of the heterogeneity of supergiant disks. Authors: Harvey, J. W.; Lynds, C. R.; Worden, S. P. Bibcode: 1977oehs.conf..405H Altcode: No abstract at ADS Title: On the origin of the 2h40m solar oscillations. Authors: Worden, S. P.; Simon, G. W. Bibcode: 1976ApJ...210L.163W Altcode: The existence of a 2-hr 40-min global solar velocity oscillation has recently been reported. The present letter examines the possibility that this phenomenon represents the rotation of large-scale solar velocity cells (supergranulation) through the field of view of the instrument used to detect the oscillations. On the basis of high-resolution full-disk velocity data, it is concluded that this mechanism can produce apparent oscillations with periods near 2 hr 40 min. Title: Reconstructed images of Alpha Orionis using stellar speckle interferometry. Authors: Worden, S. P.; Lynds, C. R.; Harvey, J. W. Bibcode: 1976JOSA...66.1243W Altcode: 1976OSAJ...66.1243W A recently developed technique to recover nearly diffraction-limited images of supergiant stars such as Alpha Orionis (Betelgeuse) from speckle interferometry data is discussed. This method relies on the digital identification and coaddition of the brightest individual speckles within a large number of short-exposure speckle photographs. The resulting average speckle may be thought of as the convolution of a point source speckle profile with the actual object intensity pattern. By making use of this point angular diameters and limb darkening coefficients are derived in addition to finding evidence of possible surface structure on the star. Title: Looking at the surfaces of other stars Authors: Worden, Simon P. Bibcode: 1976PhTea..14..514W Altcode: No abstract at ADS Title: High Spectral Resolution K Line Observations of Active Chromosphere Stars. Authors: Linsky, J. L.; Worden, S. P. Bibcode: 1976BAAS....8..519L Altcode: No abstract at ADS Title: Digital image reconstruction applied to Alpha Orionis. Authors: Lynds, C. R.; Worden, S. P.; Harvey, J. W. Bibcode: 1976ApJ...207..174L Altcode: Short-exposure photographs at high magnification have been obtained for the M2 Ia-b supergiant alpha Ori with a 4-m telescope. Optical passbands were chosen which isolate a temperature-sensitive TiO band and, for comparison, a nearby section of continuum. The photographs have been digitized and subjected to a deconvolution procedure which gives reconstructed images of the surface of the star. The images indicate a small difference in the angular dimensions of the star as observed through the two different filters, and there is some evidence supporting the presence of surface structure. The particular procedure employed in the reconstruction of the images has only a limited range of validity, but application of the procedure to photographs of the unresolved star gamma Ori not only served the necessary function of determining the final point-spread function but also yielded images showing a diffraction pattern apparently related to the theoretical Airy pattern of the telescope. Title: The emission lines in the vicinity of hydrogen-alpha in dMe flare star spectra. Authors: Worden, S. P.; Peterson, B. M. Bibcode: 1976ApJ...206L.145W Altcode: No abstract at ADS Title: Mass Loss from Dwarf M Stars Through Stellar Flaring Authors: Coleman, Gary D.; Worden, Simon P. Bibcode: 1976ApJ...205..475C Altcode: It is shown that mass loss from dwarf M stars arising from flaring and stellar winds may lead to a significant mass and energy input into the interstellar medium. It is further demonstrated that the stellar flares on these stars may be producing through nuclear reactions a large fraction of the observed interstellar deuterium. The same mass loss would also give rise to substantial galactic winds in galaxies with small ambient interstellar gas components. These results show that stellar flaring can account for many effects previously ascribed to supernovae. Subject headings: interstellar: matter - stars: flare - stars: late-type - stars: mass loss Title: On the Origin of 2h 40m Global Solar Oscillations Authors: Worden, S. P. Bibcode: 1976BAAS....8..310W Altcode: No abstract at ADS Title: Digital analysis of speckle photographs: the angular diameter of Arcturus. Authors: Worden, S. P. Bibcode: 1976PASP...88...69W Altcode: Digital reduction of speckle interferometry data for the K2 III giant a Boo (Arcturus) has been done. Angular diameters of o': 019 i 0': 006 were obtained at 4200 A for a uniformly illuminated disk, and 0,027 i 0,010 for a highly limb-darkened disk. Arcturus is underresolved using the Kitt Peak National Observatory 4-meter telescope. The digital-reduction scheme described here proved ideal for studying such underresolved objects. A discussion of limitations of this technique is also provided. Key words: speckle interferometry - atmospheric seeing - resolution Title: A study of supergranulation using a diode array magnetograph. Authors: Worden, S. P.; Simon, G. W. Bibcode: 1976SoPh...46...73W Altcode: The evolution of the velocity and magnetic fields associated with supergranulation has been investigated using the Sacramento Peak Observatory Diode Array Magnetograph. The observations consist of time sequences of simultaneous velocity, magnetic field, and chromospheric network measurements. From these data it appears that the supergranular velocity cells may have lifetimes in excess of the accepted value of 24 hours. Magnetic field motions associated with supergranulation were infrequent and seem to be accompanied by changes in the velocity field. More prevalent were the slow dissipation and diffusion of stationary flux points. Vertical velocity fields of 200 m s−1 appear to be confined to downflows in magnetic field regions at supergranular boundaries. These downflows are only observed using certain absorption lines. Corresponding upflows in the center of supergranules of less than 50 m s−1 may be present but cannot be confirmed. Title: Velocities Observed in Super-Granules Authors: Worden, S. P.; Simon, G. W. Bibcode: 1976IAUS...71..121W Altcode: No abstract at ADS Title: Reconstructed images of Alpha Orionis using stellar speckle interferometry. Authors: Worden, S. P.; Harvey, J. W.; Lynds, C. R. Bibcode: 1976JOSA...66..181W Altcode: 1976OSAJ...66..181W No abstract at ADS Title: Cryogenic test of the equivalence principle. Authors: Worden, P. W., Jr. Bibcode: 1976PhDT.......167W Altcode: No abstract at ADS Title: Astronomical image reconstruction Authors: Worden, S. P. Bibcode: 1975aifo.reptW....W Altcode: Recently proposed methods for reconstructing large telescope astronomical images free from atmospheric perturbation are reviewed and discussed. Title: Infrared Observations of Supergranule Temperature Structure Authors: Worden, S. P. Bibcode: 1975SoPh...45..521W Altcode: One and two-dimensional observations were made at 1.64 μ, the deepest observable level in the solar atmosphere; at 1.72 μ, representing the chromosphere; and at 1.17 μ, representing the visible photosphere. Structures distributed on a supergranular size scale (30000 km) are apparently present at all levels. These structures in the deep photospheric level (1.64 μ) seem to be a 50K-500K temperature decrease over surrounding photosphere confined to the magnetic field elements with horizontal scales less than 4000 km at supergranular boundaries, rather than a general temperature structure over the entire supergranule cell appropriate to convective energy transport. Title: The limitations of astronomical image reconstruction Authors: Worden, S. P. Bibcode: 1975Obs....95..291W Altcode: No abstract at ADS Title: The angular diameter of Alpha Herculis A. Authors: Worden, S. P. Bibcode: 1975ApJ...201L..69W Altcode: No abstract at ADS Title: Flare Stars and Galactic Winds Authors: Coleman, G. D.; Worden, S. P. Bibcode: 1975BAAS....7R.528C Altcode: No abstract at ADS Title: Flare stars and galactic winds. Authors: Coleman, G. D.; Worden, S. P. Bibcode: 1975BAAS....7..538C Altcode: No abstract at ADS Title: Heights of Formation of Non-Magnetic Solar Lines Suitable for Velocity Studies Authors: Altrock, R. C.; November, L. J.; Simon, G. W.; Milkey, R. W.; Worden, S. P. Bibcode: 1975SoPh...43...33A Altcode: Heights of formation of lines that do not exhibit Zeeman splitting are calculated using an LTE, partial non-LTE, and full non-LTE approach. Non-magnetic (g=0) lines are valuable for velocity investigations in quiet-Sun magnetic field regions, and a knowledge of their formation heights is useful for obtaining three dimensional velocity profiles in these regions. Title: The Character of 300-Second Oscillators. Authors: November, L. J.; Simon, G. W.; Worden, S. P. Bibcode: 1975BAAS....7..407N Altcode: No abstract at ADS Title: Mass Loss from Stellar Flares. Authors: Worden, S. P.; Coleman, G. D. Bibcode: 1975BAAS....7..398W Altcode: No abstract at ADS Title: Composition and Composition Gradients in Disk Galaxies, I Authors: Jensen, E. B.; Strom, S. E.; Worden, S. P. Bibcode: 1975BAAS....7..396J Altcode: No abstract at ADS Title: Solar supergranulation Authors: Worden, Simon Peter Bibcode: 1975PhDT.......176W Altcode: No abstract at ADS Title: Solar Supergranulation. Authors: Worden, S. P. Bibcode: 1975PhDT.........2W Altcode: A convective process originating some 10,000 km below the solar surface was studied. Several observations designed to study the process are examined. An alternate approach taken in understanding stellar convection was the study of the dMe stars. A discussion of observational results within the framework of solar and stellar convection zone-magnetic interactions is provided. Simultaneous velocity, magnetic field, and chromospheric emission network data were used to study the lifetimes, the vertical velocity flow, and the transport of magnetic fields associated with supergranulation. Horizontal magnetic field motions take two forms: (1) an apparent slow breakup of existing flux points; and (2) a rapid motion of flux following the emergence of new magnetic field. The latter may be associated with the formation of a new supergranule. Results are consistent with a generalized stellar model in which strong magnetic fields are shown to be generated deep within the star. Title: A Conjecture Regarding the dMe Stars Authors: Worden, S. P. Bibcode: 1974PASP...86..595W Altcode: The dMe stars are late-type main-sequence objects which exhibit characteristics that can be explained as the result of solar-type surface magnetic activity. The battery mechanism of Biermann (1950) is used to explain the origin of the magnetic fields responsible for the surface activity. Magnetic fields 10-100 times the strength of solar magnetic fields can be produced in this manner. Such strong fields are consistent with the observed dMe properties and should be directly detectable. Title: Narrow-band photoelectric photometry of three dMe stars. Authors: Jensen, E. B.; Worden, S. P.; Grasdalen, G. L. Bibcode: 1974PASP...86..601J Altcode: No abstract at ADS Title: Digital Image Reconstruction Applied to Betelgeuse. Authors: Lynds, C. R.; Worden, S. P.; Harvey, J. W. Bibcode: 1974BAAS....6Q.459L Altcode: No abstract at ADS Title: A digital analysis of the polarization within the Serpens nebula. Authors: Worden, S. P.; Grasdalen, G. L. Bibcode: 1974A&A....34...37W Altcode: Summary. Photographic linear polarization data was digitally analyzed to determine the illuminating source for the Serpens Nebula (oc1950 = 18h27m24s5, a1950 = +0101 2'40"). The results were two-dimensionally Fourier filtered to reduce noise. Some improvement in the data was produced in this manner. The result of this procedure indicates that the Serpens Nebula is a reflection nebula illuminated by an imbedded star and not by a nearby infrared source as suggested by Strom et aL (1974b). This illuminating star is probably a young zero age main sequence star of spectral Type B 5-A 5. Key words: polarization- reflection nebula digital analysis Title: W Ursae Majoris: mass-ratio discrepancy, third body and age. Authors: Whelan, J.; Mochnacki, S. W.; Worden, S. P. Bibcode: 1974MNRAS.168...31W Altcode: The discrepancy between the spectroscopically and photometrically determined mass-ratios of W Ursae Majoris, and the observed quasi-sinusoidal period variations may be understood if there is a third body in the system which contributes about 4 per cent of the light at maximum. The third body has a mass of about Mo and could be a Hayashi star. The time scale for its contraction to the main-sequence (5 x io8 yr) is of the same order as an estimate of the age of W Ursae Majons (i- x io yr) deduced from the time since coincidence of W Ursae Majoris and its proper motion companion BD + 55 1351. The inferred age of W Ursae Majoris may be significant for contact binary evolution theory. Several observational tests of the third-body hypothesis are proposed. The possibility that the period changes are caused by mass exchange, mass loss or apsidal motion cannot be ruled out and these mechanisms are compared with the third-body hypothesis. Title: The effects of the 35-day X-ray cycle on the light curve of HZ Herculis. Authors: Grandi, S. A.; Hintzen, P. M. N. O.; Jensen, E. B.; Rydgren, A. E.; Scott, J. S.; Stickney, P. M.; Whelan, J. A. J.; Worden, S. P. Bibcode: 1974ApJ...190..365G Altcode: We report extensive photoelectric UB V photometry of the variable star HZ Her, originally undertaken to discover possible correlations between variations in its 1.7-day light curve and the 35-day cycle of the X-ray source Her X-1. Correlations recently reported by other groups are confirmed. These, as well as other features observed, are provisionally analyzed using a model consisting of a primary star filling its Roche lobe and being illuminated by X-rays. The X-rays are emitted in a beam fixed in a rotating, precessing, neutron-star secondary. Additional light is being contributed by material being transferred from the primary to the secondary. Subject headings: binaries - stars, individual - X-ray sources Title: A Digital Analysis of the Color Structure Within Messier 51 Authors: Worden, Simon P. Bibcode: 1974PASP...86...92W Altcode: Blue and visual photographic plates of Messier 51 have been digitally analyzed to give computer produced (B- V) maps of M51. The technique used to accomplish this is described and this material is compared with the preliminary Westerbork 21-cm neutral hydrogen data. The indication of a ring of blue stars in the nucleus of M 51 is reported. Key words: Messier 51 - (B- V) maps - 21-cm contours Title: The gyroscope experiment. - III: Tests of the equivalence of gravitational and inertial mass based on cryogenic techniques Authors: Worden, P. W., Jr.; Everitt, C. W. F. Bibcode: 1974exgr.conf..381W Altcode: No abstract at ADS Title: The implications of the W Ursae Majoris type contact binary in M67. Authors: Worden, S. P.; Whelan, J. Bibcode: 1973PASP...85..540W Altcode: No abstract at ADS Title: Photoelectric UBV Photometry of HZ Herculis. Authors: Grandi, S. A.; Hintzen, P.; Jensen, E. B.; Rydgren, E.; Scott, J. S.; Stickney, P. M.; Whelan, J. A. J.; Worden, S. P. Bibcode: 1973BAAS....5Q.440G Altcode: No abstract at ADS Title: Optical Pulsations of HZ Herculis Authors: Cocke, W. J.; Hintzen, P.; Scott, J. S.; Worden, S. P. Bibcode: 1973NPhS..244Q.137C Altcode: 1973Natur.244Q.137C ON April 15.3 (UT), we attempted to detect optical variations in HZ Herculis corresponding to its 1.2 s X-ray pulsation period. No such variations were observed to a limiting magnitude of 23.5 (modulation 0.01%). Title: TX CANCRI : the golden wonder. Authors: Whelan, J. A. J.; Worden, S. P.; Mochnacki, S. W. Bibcode: 1973ApJ...183..133W Altcode: Spectroscopic, photometric, and polarimetric observations of TX Cancri, a W UMa-type binary system in Praesepe, are reported. The parameters (masses, radii, luminosities) of the components of the system are determined. If the system is evolved, then it must have lost a substantial amount of mass to reach its present state. We argue that TX Cnc is unevolved, and an age-zero contact-binary model for the system is constructed. Problems in the interpretation of the parameters of the system and the age-zero model are discussed. Subject headings: eclipsing binaries - open clusters - stars, individual - W Ursae Majoris stars Title: The He+ λ 4686 line in the low chromosphere Authors: Worden, S. P.; Beckers, J. M.; Hirayama, T. Bibcode: 1973SoPh...28...27W Altcode: We report an unsuccessful search for the He+ λ 4686 line in the low chromosphere. However, at the location of this line we detect a number of other chromospheric emission lines. This leads us to the conclusion that the He+ λ 4686 identification made in the past, as well as other identifications, are probably in error. Additionally the region of the neutral helium λ4713 line is also studied. Title: W Ursae Majoris: the parameters of a contact binary. Authors: Worden, S. P.; Whelan, J. Bibcode: 1973MNRAS.163..391W Altcode: Spectroscopic radial velocity observations of W Ursae Majoris, the prototype contact binary, are reported. The parameters (masses, radii, luminosities) of the system have been determined and are given in Table V. There is a real discrepancy between the spectroscopically determined mass-ratio of W Ursae Majoris and the photometrically determined one. BD +55 1351 and W Ursae Majoris share the same space motion which provides an estimate of the distance to the system. A theoretical main-sequence contact binary model is constructed which reproduces the observations. Title: The Mass-Ratio of W UMa. Authors: Worden, S. P.; Whelan, J. Bibcode: 1973BAAS....5R..42W Altcode: No abstract at ADS Title: HZ Herculis. Authors: Cocke, W. J.; Hintzen, P.; Scott, J. S.; Worden, S. P. Bibcode: 1973IAUC.2543R...1C Altcode: No abstract at ADS Title: TX Cancri. Authors: Whelan, J.; Worden, S. P.; Mochnacki, S. W. Bibcode: 1972BAAS....4Q.330W Altcode: No abstract at ADS Title: Note on the Energy Scale of the Michigan OSO III Ion Chamber Authors: Teske, Richard G.; Hodge, Philip E.; Worden, Simon P. Bibcode: 1972SoPh...22..235T Altcode: The energy scale of the Michigan OSO III soft X-ray ion chamber has been assessed by using realistic theoretical X-ray spectra. Multiplicative factors by which the data may be corrected are proposed. The factors are only slightly temperature-dependent. A test of the proposed energy scale indicates it is still somewhat uncertain. Title: Re-evaluation of the Energy Scale of the Michigan OSO III Ion Chamber Soft X-Ray Photometer. Authors: Teske, R. G.; Hodge, P. W.; Worden, S. P. Bibcode: 1971BAAS....3R.439T Altcode: No abstract at ADS