kurucz

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Author name code: kurucz
ADS astronomy entries on 2022-09-14
author:"Kurucz, Robert L."

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Title: Stellar limb darkening. A new MPS-ATLAS library for Kepler,
TESS, CHEOPS, and PLATO passbands
Authors: Kostogryz, N. M.; Witzke, V.; Shapiro, A. I.; Solanki, S. K.;
Maxted, P. F. L.; Kurucz, R. L.; Gizon, L.
2022arXiv220606641K Altcode:
The detection of the first exoplanet paved the way into the era of
transit photometry space missions with a revolutionary photometric
precision that aim at discovering new exoplanetary systems around
different types of stars. With this high precision, it is possible
to derive very accurately the radii of exoplanets which is crucial
for constraining their type and composition. However, it requires an
accurate description of host stars, especially their center-to-limb
variation of intensities (so called limb darkening) as it affects the
planet-to-star radius ratio determination. We aim at improving the
accuracy of limb darkening calculations for stars with a wide range
of fundamental parameters. We used the recently developed 1D MPS-ATLAS
code to compute model atmosphere structures and to synthesize stellar
limb darkening on a very fine grid of stellar parameters. For the
computations we utilized the most accurate information on chemical
element abundances and mixing length parameters including convective
overshoot. The stellar limb darkening was fitted using the two most
accurate limb darkening laws: the power-2 and 4-parameters non-linear
laws. We present a new extensive library of stellar model atmospheric
structures, the synthesized stellar limb darkening curves, and the
coefficients of parameterized limb-darkening laws on a very fine grid of
stellar parameters in the Kepler, TESS, CHEOPS, and PLATO passbands. The
fine grid allows overcoming the sizable errors introduced by the need
to interpolate. Our computations of solar limb darkening are in a
good agreement with available solar measurements at different view
angles and wavelengths. Our computations of stellar limb darkening
agree well with available measurements of Kepler stars. A new grid of
stellar model structures, limb darkening and their fitted coefficients
in different broad filters is provided in CDS.

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Title: New Fe I Level Energies and Line Identifications from Stellar
Spectra. III. Initial Results from UV, Optical, and Infrared Spectra
Authors: Peterson, Ruth C.; Kurucz, Robert L.
2022ApJS..260...28P Altcode: 2021arXiv211214742P
The spectrum of neutral iron is critical to astrophysics, yet furnace
laboratory experiments cannot reach high-lying Fe I levels. Instead,
Peterson &amp; Kurucz and Peterson et al. adopted ultraviolet (UV) and
optical spectra of warm stars to identify and assign energies for 124 Fe
I levels with 1900 detectable Fe I lines, and to derive astrophysical
gf values for over 1000 of these. An energy value was assumed for
each unknown Fe I level, and confirmed if the wavelengths predicted
in updated Kurucz Fe I calculations matched the wavelengths of four
or more unidentified lines in the observed spectra. Nearly all these
identifications were for LS levels, those characterized by spin-orbit
coupling, whose lines fall primarily at UV and optical wavelengths. This
work contributes nearly 100 new Fe I level identifications. Thirty-nine
LS levels are identified largely by incorporating published positions
of unidentified laboratory Fe I lines with wavelengths &lt;2000
Å. Adding infrared (IR) spectra provided 60 Fe I jK levels, where a
single outer electron orbits a compact core. Their weak IR lines are
searchable, because their mutual energies obey tight relationships. For
each new Fe I level, this work again makes publicly available its
identification, its energy, and a list of its potentially detectable
lines with theoretical gf values, totalling &gt;16,000 lines. For over
2000 of these, this work provides astrophysical gf values adjusted
semiempirically to fit the stellar spectra. The potential impact of
this work on modeling UV and IR stellar spectra is noted.

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Title: MPS-ATLAS: A fast all-in-one code for synthesising stellar
spectra
Authors: Witzke, V.; Shapiro, A. I.; Cernetic, M.; Tagirov, R. V.;
Kostogryz, N. M.; Anusha, L. S.; Unruh, Y. C.; Solanki, S. K.; Kurucz,
R. L.
2021A&A...653A..65W Altcode: 2021arXiv210513611W
Context. Stellar spectral synthesis is essential for various
applications, ranging from determining stellar parameters to
comprehensive stellar variability calculations. New observational
resources as well as advanced stellar atmosphere modelling, taking three
dimensional effects from radiative magnetohydrodynamics calculations
into account, require a more efficient radiative transfer. Aims:
For accurate, fast and flexible calculations of opacity distribution
functions (ODFs), stellar atmospheres, and stellar spectra, we developed
an efficient code building on the well-established ATLAS9 code. The new
code also paves the way for easy and fast access to different elemental
compositions in stellar calculations. Methods: For the generation
of ODF tables, we further developed the well-established DFSYNTHE code
by implementing additional functionality and a speed-up by employing
a parallel computation scheme. In addition, the line lists used can be
changed from Kurucz's recent lists. In particular, we implemented the
VALD3 line list. Results: A new code, the Merged Parallelised
Simplified ATLAS, is presented. It combines the efficient generation of
ODF, atmosphere modelling, and spectral synthesis in local thermodynamic
equilibrium, therefore being an all-in-one code. This all-in-one code
provides more numerical functionality and is substantially faster
compared to other available codes. The fully portable MPS-ATLAS code
is validated against previous ATLAS9 calculations, the PHOENIX code
calculations, and high-quality observations.

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Title: HELIOS-K 2.0 Opacity Calculator and Open-source Opacity
Database for Exoplanetary Atmospheres
Authors: Grimm, Simon L.; Malik, Matej; Kitzmann, Daniel; Guzmán-Mesa,
Andrea; Hoeijmakers, H. Jens; Fisher, Chloe; Mendonça, João
M.; Yurchenko, Sergey N.; Tennyson, Jonathan; Alesina, Fabien;
Buchschacher, Nicolas; Burnier, Julien; Segransan, Damien; Kurucz,
Robert L.; Heng, Kevin
2021ApJS..253...30G Altcode: 2021arXiv210102005G
Computing and using opacities is a key part of modeling and interpreting
data of exoplanetary atmospheres. Since the underlying spectroscopic
line lists are constantly expanding and currently include up to
∼1010-1011 transition lines, the opacity
calculator codes need to become more powerful. Here we present
major upgrades to the HELIOS-K GPU-accelerated opacity calculator
and describe the necessary steps to process large line lists within
a reasonable amount of time. Besides performance improvements, we
include more capabilities and present a toolbox for handling different
atomic and molecular data sets, from downloading and preprocessing
the data to performing the opacity calculations in a user-friendly
way. HELIOS-K supports line lists from ExoMol, HITRAN, HITEMP, NIST,
Kurucz, and VALD3. By matching the resolution of 0.1 cm-1
and cutting length of 25 cm-1 used by the ExoCross code for
timing performance (251 s excluding data read-in time), HELIOS-K can
process the ExoMol BT2 water line list in 12.5 s. Using a resolution of
0.01 cm-1, it takes 45 s, equivalent to about 107
lines s-1. As a wavenumber resolution of 0.01 cm-1
suffices for most exoplanetary atmosphere spectroscopic calculations,
we adopt this resolution in calculating opacity functions for several
hundred atomic and molecular species and make them freely available
on the open-access DACE database. For the opacity calculations of
the database, we use a cutting length of 100 cm-1 for
molecules and no cutting length for atoms. Our opacities are available
for downloading from https://dace.unige.ch/opacityDatabase and may be
visualized using https://dace.unige.ch/opacity.

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Title: Helium Enhancement in the Metal-rich Red Giants of ω Centauri
Authors: Hema, B. P.; Pandey, Gajendra; Kurucz, R. L.; Allende
Prieto, C.
2020ApJ...897...32H Altcode: 2020arXiv200506807H
The helium-enriched (He-enriched) metal-rich red giants of ω
Centauri, discovered by Hema &amp; Pandey using the low-resolution
spectra from the Vainu Bappu Telescope, and confirmed by the analyses
of the high-resolution spectra obtained from the HRS-South African
Large Telescope for LEID 34225 and LEID 39048, are reanalyzed here
to determine their degree of He enhancement/hydrogen deficiency (H
deficiency). The observed MgH band combined with model atmospheres with
differing He/H ratios are used for the analyses. The He/H ratios of
these two giants are determined by enforcing the fact that the derived
Mg abundances from the Mg I lines and from the subordinate lines of the
MgH band must be same for the adopted model atmosphere. The estimated
He/H ratios for LEID 34225 and LEID 39048 are 0.15 ± 0.04 and 0.20 ±
0.04, respectively, whereas the normal He/H ratio is 0.10. Following the
same criteria for the analyses of the other two comparison stars (LEID
61067 and LEID 32169), a normal He/H ratio of 0.10 is obtained. The
He/H ratio of 0.15-0.20 corresponds to a mass fraction of helium
(Z(He) = Y) of about 0.375-0.445. The range of helium enhancement
and the derived metallicity of the program stars are in line with
those determined for ω Cen's blue main-sequence stars. Hence, our
study provides the missing link for the evolutionary track of the
metal-rich helium-enhanced population of ω Centuari. This research
work is the very first spectroscopic determination of the amount of
He enhancement in the metal-rich red giants of ω Centauri using the
Mg I and MgH lines.

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Title: Update of the HITRAN collision-induced absorption section
Authors: Karman, Tijs; Gordon, Iouli E.; van der Avoird, Ad; Baranov,
Yury I.; Boulet, Christian; Drouin, Brian J.; Groenenboom, Gerrit C.;
Gustafsson, Magnus; Hartmann, Jean-Michel; Kurucz, Robert L.; Rothman,
Laurence S.; Sun, Kang; Sung, Keeyoon; Thalman, Ryan; Tran, Ha;
Wishnow, Edward H.; Wordsworth, Robin; Vigasin, Andrey A.; Volkamer,
Rainer; van der Zande, Wim J.
2019Icar..328..160K Altcode:
Correct parameterization of the Collision-induced Absorption
(CIA) phenomena is essential for accurate modeling of planetary
atmospheres. The HITRAN spectroscopic database provides these parameters
in a dedicated section. Here, we significantly revise and extend
the HITRAN CIA data with respect to the original effort described
in Richard et al. [JQSRT 113, 1276 (2012)]. The extension concerns
new collisional pairs as well as wider spectral and temperature
ranges for the existing pairs. The database now contains CIA for
N2sbnd N2, N2sbnd H2,
N2sbnd CH4, N2sbnd H2O,
N2sbnd O2, O2sbnd O2,
O2sbnd CO2, CO2sbnd CO2,
H2sbnd H2, H2sbnd He, H2sbnd
CH4, H2sbnd H, Hsbnd He, CH4sbnd
CH4, CH4sbnd CO2, CH4sbnd
He, and CH4sbnd Ar collision pairs. The sources of data as
well as their validation and selection are discussed. A wish list to
eliminate remaining deficiencies or lack of data from the astrophysics
perspective is also presented.

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Title: Including All the Lines: Data Releases for Spectra and
Opacities through 2017
Authors: Kurucz, R. L.
2018ASPC..515...47K Altcode:
I present a progress report on including all the lines in the line
lists, including all the lines in the opacities, and including all the
lines in the model atmosphere and spectrum synthesis calculations. The
increased opacity will improve stellar atmosphere, pulsation,
stellar interior, asteroseismology, nova, supernova, and other
radiation-hydrodynamics calculations. At present I have produced atomic
line data for computing opacities for 850 million lines for elements up
to Zn and for the 4d elements from Sr through Pd. Of these, 2.31 million
lines are between known energy levels, so they have good wavelengths
for computing spectra. Work is continuing on Ga to Rb and on heavier
elements. Data for each ion and merged line lists are available on my
website &lt;a href='kurucz.harvard.edu'&gt;kurucz.harvard.edu&lt;/a&gt;.

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Title: High Resolution Near-Infrared Spectroscopy of Cool Dwarf Stars
Authors: Dupree, Andrea; Brickhouse, Nancy; Irwin, Jonathan; Kurucz,
Robert; Newton, Elisabeth
2018csss.confE..87D Altcode: 2018arXiv181105572D
We present results from a near infrared survey of the He I line (10830
Angstrom) in cool dwarf stars taken with the PHOENIX spectrograph at
the 4-m Mayall telescope at Kitt Peak National Observatory. Spectral
synthesis of this region reproduces some but not all atomic and
molecular features. The equivalent width of the He line appears directly
correlated with the soft X-ray stellar surface flux except among the
coolest M dwarf stars, where the helium is surprisingly weak.

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Title: Stellar Atmospheric Modelling for the ACCESS Program
Authors: Morris, Matthew; Kaiser, Mary Elizabeth; Bohlin, Ralph;
Kurucz, Robert; ACCESS Team
2018AAS...23135527M Altcode:
A goal of the ACCESS program (Absolute Color Calibration Experiment for
Standard Stars) is to enable greater discrimination between theoretical
astrophysical models and observations, where the comparison is limited
by systematic errors associated with the relative flux calibration
of the targets. To achieve these goals, ACCESS has been designed as
a sub-orbital rocket borne payload and ground calibration program,
to establish absolute flux calibration of stellar targets at &lt;1
% precision, with a resolving power of 500 across the 0.35 to 1.7
micron bandpass.In order to obtain higher resolution spectroscopy in
the optical and near-infrared range than either the ACCESS payload
or CALSPEC observations provide, the ACCESS team has conducted a
multi-instrument observing program at Apache Point Observatory. Using
these calibrated high resolution spectra in addition to the HST/CALSPEC
data, we have generated stellar atmosphere models for ACCESS flight
candidates, as well as a selection of A and G stars from the CALSPEC
database. Stellar atmosphere models were generated using Atlas 9 and
Atlas 12 Kurucz stellar atmosphere software. The effective temperature,
log(g), metallicity, and redenning were varied and the chi-squared
statistic was minimized to obtain a best-fit model. A comparison
of these models and the results from interpolation between grids
of existing models will be presented. The impact of the flexibility
of the Atlas 12 input parameters (e.g. solar metallicity fraction,
abundances, microturbulent velocity) is being explored.

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Title: ACCESS, Absolute Color Calibration Experiment for Standard
Stars: Integration, Test, and Ground Performance
Authors: Kaiser, Mary Elizabeth; Morris, Matthew; Aldoroty, Lauren;
Kurucz, Robert; McCandliss, Stephan; Rauscher, Bernard; Kimble, Randy;
Kruk, Jeffrey; Wright, Edward L.; Feldman, Paul; Riess, Adam; Gardner,
Jonathon; Bohlin, Ralph; Deustua, Susana; Dixon, Van; Sahnow, David
J.; Perlmutter, Saul
2018AAS...23135534K Altcode:
Establishing improved spectrophotometric standards is important
for a broad range of missions and is relevant to many astrophysical
problems. Systematic errors associated with astrophysical data used to
probe fundamental astrophysical questions, such as SNeIa observations
used to constrain dark energy theories, now exceed the statistical
errors associated with merged databases of these measurements. ACCESS,
“Absolute Color Calibration Experiment for Standard Stars”, is a
series of rocket-borne sub-orbital missions and ground-based experiments
designed to enable improvements in the precision of the astrophysical
flux scale through the transfer of absolute laboratory detector
standards from the National Institute of Standards and Technology
(NIST) to a network of stellar standards with a calibration accuracy
of 1% and a spectral resolving power of 500 across the 0.35-1.7μm
bandpass. To achieve this goal ACCESS (1) observes HST/ Calspec stars
(2) above the atmosphere to eliminate telluric spectral contaminants
(e.g. OH) (3) using a single optical path and (HgCdTe) detector (4)
that is calibrated to NIST laboratory standards and (5) monitored on
the ground and in-flight using a on-board calibration monitor. The
observations are (6) cross-checked and extended through the generation
of stellar atmosphere models for the targets. The ACCESS telescope and
spectrograph have been designed, fabricated, and integrated. Subsystems
have been tested. Performance results for subsystems, operations
testing, and the integrated spectrograph will be presented. NASA
sounding rocket grant NNX17AC83G supports this work.

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Title: ATLAS9: Model atmosphere program with opacity distribution
functions
Authors: Kurucz, Robert L.
2017ascl.soft10017K Altcode:
ATLAS9 computes model atmospheres using a fixed set of pretabulated
opacities, allowing one to work on huge numbers of stars and interpolate
in large grids of models to determine parameters quickly. The code
works with two different sets of opacity distribution functions (ODFs),
one with "big" wavelength intervals covering the whole spectrum and
the other with 1221 "little" wavelength intervals covering the whole
spectrum. The ODFs use a 12-step representation; the radiation field is
computed starting with the highest step and working down. If a lower
step does not matter because the line opacity is small relative to
the continuum at all depths, all the lower steps are lumped together
and not computed to save time.

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Title: ACCESS: integration and pre-flight performance
Authors: Kaiser, Mary Elizabeth; Morris, Matthew J.; Aldoroty, Lauren
N.; Pelton, Russell; Kurucz, Robert; Peacock, Grant O.; Hansen, Jason;
McCandliss, Stephan R.; Rauscher, Bernard J.; Kimble, Randy A.; Kruk,
Jeffrey W.; Wright, Edward L.; Orndorff, Joseph D.; Feldman, Paul D.;
Moos, H. Warren; Riess, Adam G.; Gardner, Jonathan P.; Bohlin, Ralph;
Deustua, Susana E.; Dixon, W. V.; Sahnow, David J.; Perlmutter, Saul
2017SPIE10398E..15K Altcode:
Establishing improved spectrophotometric standards is important for
a broad range of missions and is relevant to many astrophysical
problems. ACCESS, "Absolute Color Calibration Experiment for
Standard Stars", is a series of rocket-borne sub-orbital missions
and ground-based experiments designed to enable improvements in the
precision of the astrophysical flux scale through the transfer of
absolute laboratory detector standards from the National Institute
of Standards and Technology (NIST) to a network of stellar standards
with a calibration accuracy of 1% and a spectral resolving power of 500
across the 0.35 - 1.7μm bandpass. This paper describes the sub-system
testing, payload integration, avionics operations, and data transfer
for the ACCESS instrument.

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Title: VizieR Online Data Catalog: New FeI level energies from
stellar spectra. II. (Peterson+, 2017)
Authors: Peterson, R. C.; Kurucz, R. L.; Ayres, T. R.
2017yCat..22290023P Altcode:
All of the new space-based UV spectra were obtained at a two-pixel
resolution of 110000 with the E230H echelle grating of the Space
Telescope Imaging Spectrograph (STIS) on HST, under program GO-14161
(R. Peterson, PI). See section 2 for further explanations. (2
data files).

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Title: New Fe I Level Energies and Line Identifications from
Stellar Spectra. II. Initial Results from New Ultraviolet Spectra
of Metal-poor Stars
Authors: Peterson, Ruth C.; Kurucz, Robert L.; Ayres, Thomas R.
2017ApJS..229...23P Altcode:
The Fe I spectrum is critical to many areas of astrophysics, yet many of
the high-lying levels remain uncharacterized. To remedy this deficiency,
Peterson &amp; Kurucz identified Fe I lines in archival ultraviolet
and optical spectra of metal-poor stars, whose warm temperatures favor
moderate Fe I excitation. Sixty-five new levels were recovered, with
1500 detectable lines, including several bound levels in the ionization
continuum of Fe I. Here, we extend the previous work by identifying
59 additional levels, with 1400 detectable lines, by incorporating new
high-resolution UV spectra of warm metal-poor stars recently obtained
by the Hubble Space Telescope Imaging Spectrograph. We provide gf
values for these transitions, both computed as well as adjusted to
fit the stellar spectra. We also expand our spectral calculations to
the infrared, confirming three levels by matching high-quality spectra
of the Sun and two cool stars in the H-band. The predicted gf values
suggest that an additional 3700 Fe I lines should be detectable
in existing solar infrared spectra. Extending the empirical line
identification work to the infrared would help confirm additional Fe I
levels, as would new high-resolution UV spectra of metal-poor turnoff
stars below 1900 Å.

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Title: Chromospheric Models and the Oxygen Abundance in Giant Stars
Authors: Dupree, A. K.; Avrett, E. H.; Kurucz, R. L.
2016ApJ...821L...7D Altcode: 2016arXiv160307381D
Realistic stellar atmospheric models of two typical metal-poor giant
stars in Omega Centauri, which include a chromosphere (CHR), influence
the formation of optical lines of O I: the forbidden lines (λ6300,
λ6363) and the infrared triplet (λλ7771-7775). One-dimensional
semi-empirical non-local thermodynamic equilibrium (LTE) models are
constructed based on observed Balmer lines. A full non-LTE formulation
is applied for evaluating the line strengths of O I, including
photoionization by the Lyman continuum and photoexcitation by Lyα and
Lyβ. Chromospheric models (CHR) yield forbidden oxygen transitions
that are stronger than those in radiative/convective equilibrium (RCE)
models. The triplet oxygen lines from high levels also appear stronger
than those produced in an RCE model. The inferred oxygen abundance
from realistic CHR models for these two stars is decreased by factors
of ∼3 as compared to values derived from RCE models. A lower oxygen
abundance suggests that intermediate-mass AGB stars contribute to the
observed abundance pattern in globular clusters. A change in the oxygen
abundance of metal-poor field giants could affect models of deep mixing
episodes on the red giant branch. Changes in the oxygen abundance can
impact other abundance determinations that are critical to astrophysics,
including chemical tagging techniques and galactic chemical evolution.

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Title: ACCESS Sub-system Performance
Authors: Kaiser, Mary Elizabeth; Morris, Matthew J.; Aldoroty, Lauren
Nicole; Godon, David; Pelton, Russell; McCandliss, Stephan R.; Kurucz,
Robert L.; Kruk, Jeffrey W.; Rauscher, Bernard J.; Kimble, Randy A.;
Wright, Edward L.; Benford, Dominic J.; Gardner, Jonathan P.; Feldman,
Paul D.; Moos, H. Warren; Riess, Adam G.; Bohlin, Ralph; Deustua,
Susana E.; Dixon, William Van Dyke; Sahnow, David J.; Lampton, Michael;
Perlmutter, Saul
2016AAS...22714732K Altcode:
ACCESS: Absolute Color Calibration Experiment for Standard Stars is a
series of rocket-borne sub-orbital missions and ground-based experiments
designed to leverage significant technological advances in detectors,
instruments, and the precision of the fundamental laboratory standards
used to calibrate these instruments to enable improvements in the
precision of the astrophysical flux scale through the transfer of
laboratory absolute detector standards from the National Institute
of Standards and Technology (NIST) to a network of stellar standards
with a calibration accuracy of 1% and a spectral resolving power of 500
across the 0.35 to 1.7 micron bandpass.A cross wavelength calibration
of the astrophysical flux scale to this level of precision over this
broad a bandpass is relevant for the data used to probe fundamental
astrophysical problems such as the SNeIa photometry based measurements
used to constrain dark energy theories.We will describe the strategy
for achieving this level of precision, the payload and calibration
configuration, present sub-system test data, and the status and
preliminary performance of the integration and test of the spectrograph
and telescope. NASA APRA sounding rocket grant NNX14AH48G supports
this work.

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Title: The Intersection of Atomic Physics and Astrophysics:
Identifying UV Fe I Lines from Metal-Poor Turnoff Stars
Authors: Peterson, Ruth C.; Ayres, Thomas R.; Kurucz, Robert L.
2015hst..prop14161P Altcode:
Observational surveys are expanding, recording ever-fainter sources
from the ultraviolet to the infrared. Needed to characterize them are
observational ultraviolet templates at high spectral resolution and low
metallicity for the oldest populations, and the laboratory astrophysics
data essential to model objects such as stars and nebulae at all ages,
metallicities, and redshifts. We address this by proposing to
complete the high-resolution UV spectral coverage of four key metal-poor
turnoff stars. These are ideal as metal-poor templates of old stars and
as the "laboratory source" for the identification of the thousands of
lines of neutral iron that appear in stellar spectra, but are absent
from or not identified in laboratory spectra. By matching existing
stellar spectra to calculations of energy levels, line wavelengths,
and gf-values, Peterson &amp; Kurucz (2015) identified 66 Fe I levels
with energies up to 8.4eV, yielding 2000 new lines from 1600 Angstroms
to 5.4 microns, and empirical gf-values for 640 of these. The proposed
work should yield ~500 new levels and ~10,000 new Fe I lines. The
new energy levels and line parameters also will be posted on the Kurucz
website. The new spectra, and supporting theoretical calculations,
will be integrated into the publicly available HST Advanced Spectral
Library (ASTRAL) Treasury Project. This will leverage the utility of
these archival spectral templates and atlases in such diverse areas as
nucleosynthesis at early epochs, infrared analysis of dust-obscured
giants, reconstructing the populations of nearby globular clusters
and dwarf galaxies from their integrated light, and deriving age and
metallicity for old, distant galaxies.

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Title: New Mn II energy levels from the STIS-HST spectrum of the
HgMn star HD 175640
Authors: Castelli, F.; Kurucz, R. L.; Cowley, C. R.
2015A&A...580A..10C Altcode: 2015arXiv150407514C
 Aims: The NIST database lists several Mn ii lines that were
observed in the laboratory but not classified. They cannot be used in
spectrum synthesis because their atomic line data are unknown. These
lines are concentrated in the 2380-2700 Å interval. We aimed
to assign energy levels and log gf values to these lines. 
Methods: Semi-empirical line data for Mn ii computed by Kurucz were
used to synthesize the ultraviolet spectrum of the slow-rotating, HgMn
star HD 175640. The spectrum was compared with the high-resolution
spectrum observed with the HST-STIS equipment. A UVES spectrum
covering the 3050-10 000 Å region was also examined. Results:
We determined a total of 73 new energy levels, 58 from the STIS
spectrum of HD 175640 and another 15 from the UVES spectrum. The
new energy levels give rise to numerous new computed lines. We have
identified more than 50% of the unclassified lines listed in the NIST
database and have changed the assignment of another 24 lines. An
abundance analysis of the star HD 175640, based on the comparison
of observed and computed ultraviolet spectra in the 1250-3040 Å
interval, is the by-product of this study on Mn ii. Tables
A.1 and A.2 are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/580/A10">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/580/A10</A>

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Title: VizieR Online Data Catalog: New MnII energy levels (Castelli+,
2015)
Authors: Castelli, F.; Kurucz, R. L.; Cowley, C. R.
2015yCat..35800010C Altcode:
New MnII energy levels were determined from the analysis of an
ultraviolet HST-STIS spectrum and a UVES optical spectrum. For each
new level, the most significant lines from the level are listed in
tablea1.dat. For each new line the wavelength, the computed loggf
value, and the upper and lower energy levels are given. tablea2.dat
tabulates the MnII lines in the 2400-3040Å interval that are listed in
the NIST database, observed in the spectrum, but not predicted by the
MnII line list computed by Kurucz for this paper. (2 data files).

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Title: VizieR Online Data Catalog: New FeI level energies from
stellar spectra (Peterson+, 2015)
Authors: Peterson, R. C.; Kurucz, R. L.
2015yCat..22160001P Altcode:
The spectrum of the Fe I atom is critical to many areas of astrophysics
and beyond. Measurements of the energies of its high-lying levels remain
woefully incomplete, however, despite extensive laboratory and solar
analysis. In this work, we use high-resolution archival absorption-line
ultraviolet and optical spectra of stars whose warm temperatures favor
moderate Fe I excitation. We derive the energy for a particular upper
level in Kurucz's semiempirical calculations by adopting a trial value
that yields the same wavelength for a given line predicted to be about
as strong as that of a strong unidentified spectral line observed in
the stellar spectra, then checking the new wavelengths of other strong
predicted transitions that share the same upper level for coincidence
with other strong observed unidentified lines. To date, this analysis
has provided the upper energies of 66 Fe I levels. Many new energy
levels are higher than those accessible to laboratory experiments;
several exceed the Fe I ionization energy. These levels provide new
identifications for over 2000 potentially detectable lines. Almost all
of the new levels of odd parity include UV lines that were detected
but unclassified in laboratory Fe I absorption spectra, providing
an external check on the energy values. We motivate and present
the procedure, provide the resulting new energy levels and their
uncertainties, list all the potentially detectable UV and optical new
Fe I line identifications and their gf values, point out new lines of
astrophysical interest, and discuss the prospects for additional Fe
I energy level determinations. (3 data files).

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Title: Identifying New Fe I Levels from Stellar Spectra
Authors: Peterson, Ruth; Kurucz, Robert L.
2015AAS...22544906P Altcode:
The spectrum of the Fe I atom is critical to many areas of astrophysics
and beyond. Measurements of the energies of its high-lying levels
remain woefully incomplete, however, despite extensive laboratory and
solar analysis. Here we discuss work by Peterson &amp; Kurucz (2014,
ApJS, in press) to identify such levels using high-resolution archival
absorption-line ultraviolet and optical spectra of stars, whose warm
temperatures favor moderate Fe I excitation. To date this analysis
has provided the upper energies of 66 Fe I levels. Many are of higher
excitation than is accessible to laboratory experiments; several exceed
the Fe I ionization energy. These levels provide new identifications
for over two thousand potentially detectable lines. We describe and
illustrate our method, which is based on matching the strengths and
positions of unidentified spectral features to the lines sharing a
particular upper level in Kurucz's semi-empirical calculations. We
also highlight the improvements these new identifications bring to the
determination of the abundances of trace elements in individual stars,
and to the ability of calculations of cool stellar spectra to match
low-resolution observations of stars and old stellar systems.

---------------------------------------------------------
Title: New Fe I Level Energies and Line Identifications from Stellar
Spectra
Authors: Peterson, Ruth C.; Kurucz, Robert L.
2015ApJS..216....1P Altcode: 2014arXiv1406.0933P
The spectrum of the Fe I atom is critical to many areas of astrophysics
and beyond. Measurements of the energies of its high-lying levels remain
woefully incomplete, however, despite extensive laboratory and solar
analysis. In this work, we use high-resolution archival absorption-line
ultraviolet and optical spectra of stars whose warm temperatures favor
moderate Fe I excitation. We derive the energy for a particular upper
level in Kurucz's semiempirical calculations by adopting a trial value
that yields the same wavelength for a given line predicted to be about
as strong as that of a strong unidentified spectral line observed in
the stellar spectra, then checking the new wavelengths of other strong
predicted transitions that share the same upper level for coincidence
with other strong observed unidentified lines. To date, this analysis
has provided the upper energies of 66 Fe I levels. Many new energy
levels are higher than those accessible to laboratory experiments;
several exceed the Fe I ionization energy. These levels provide new
identifications for over 2000 potentially detectable lines. Almost all
of the new levels of odd parity include UV lines that were detected
but unclassified in laboratory Fe I absorption spectra, providing
an external check on the energy values. We motivate and present
the procedure, provide the resulting new energy levels and their
uncertainties, list all the potentially detectable UV and optical new
Fe I line identifications and their gf values, point out new lines of
astrophysical interest, and discuss the prospects for additional Fe
I energy level determinations.

---------------------------------------------------------
Title: ACCESS: status and pre-flight performance
Authors: Kaiser, Mary Elizabeth; Morris, Matthew J.; Peacock, Grant O.;
McCandliss, Stephan R.; Rauscher, Bernard J.; Kimble, Randy A.; Kruk,
Jeffrey W.; Pelton, Russell; Wright, Edward L.; Mott, D. Brent; Wen,
Yiting; Feldman, Paul D.; Moos, H. Warren; Riess, Adam G.; Gardner,
Jonathan P.; Benford, Dominic J.; Woodgate, Bruce E.; Bohlin, Ralph;
Deustua, Susana E.; Dixon, W. V.; Sahnow, David J.; Kurucz, Robert;
Lampton, Michael; Perlmutter, Saul
2014SPIE.9143E..4YK Altcode:
Establishing improved spectrophotometric standards is important for
a broad range of missions and is relevant to many astrophysical
problems. ACCESS, Absolute Color Calibration Experiment for
Standard Stars", is a series of rocket-borne sub-orbital missions
and ground-based experiments designed to enable improvements in the
precision of the astrophysical flux scale through the transfer of
absolute laboratory detector standards from the National Institute of
Standards and Technology (NIST) to a network of stellar standards with a
calibration accuracy of 1% and a spectral resolving power of 500 across
the 0.35 - 1.7μm bandpass. This paper describes the payload status,
sub-system testing, and data transfer for the ACCESS instrument.

---------------------------------------------------------
Title: RR Lyrae studies with Kepler: showcasing RR Lyr
Authors: Kolenberg, Katrien; Kurucz, Robert L.; Stellingwerf, Robert;
Nemec, James M.; Moskalik, Paweł; Fossati, Luca; Barnes, Thomas G.
2014IAUS..301..257K Altcode:
Four years into the Kepler mission, an updated review on the results
for RR Lyrae stars is in order. More than 50 RR Lyrae stars in the
Kepler field are observed with Kepler and each one of them can provide
us with new insight into this class of pulsating stars. Ground-based
spectroscopy of the Kepler targets allows us to narrow down their
physical parameters. Previously, we already reported a 50% occurrence
rate of modulation in the RRab stars, a large variety of modulation
behavior, period doubling in several Blazhko stars, the detection
of higher- overtone radial modes, probable non-radial modes and new
types of multiple-mode RR Lyrae pulsators, among both the RRab and
the RRc stars. In addition, the quasi-continuous photometry obtained
over several years with Kepler allows one to observe changes in Blazhko
behavior and additional longer cycles. These observations have sparked
new theoretical modelling efforts. In this short paper we showcase RR
Lyr itself. The star has been observed with Kepler in short cadence,
and some remarkable features of its pulsation behavior are unveiled
in this long-studied prototype, through the Kepler photometry and
additional spectroscopic data.

---------------------------------------------------------
Title: Model Atmosphere Codes: ATLAS12 and ATLAS9
Authors: Kurucz, Robert L.
2014dapb.book...39K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: High-cadence high-resolution spectroscopy of the prototype
RR Lyrae
Authors: Kolenberg, Katrien; Bergstrom, Z.; Kurucz, R. L.; Fossati,
L.; Barnes, T. G.; Bergstrom, Zoey; Kurucz, Robert L.; Barnes, Thomas
G.; Fossati, Luca
2014AAS...22315626K Altcode:
RR Lyrae stars play an important role in astrophysics as standard
candles and tracers of galactic history, but several aspects of their
pulsation remain mysterious. RR Lyr, the prototype of the class,
has been studied for over a century. Recently, it was observed in
high (1-minute) cadence by the Kepler spacecraft, revealing several
new features of its pulsation. We present a set of high-cadence,
high-resolution spectra that were obtained simultaneously with the
short-cadence photometry in the star and that allow us to study the
star's photospheric dynamics in detail.

---------------------------------------------------------
Title: ACCESS: Thermal Mechanical Design, Performance, and Status
Authors: Kaiser, Mary Elizabeth; Morris, M. J.; McCandliss, S. R.;
Rauscher, B. J.; Kimble, R. A.; Kruk, J. W.; Wright, E. L.; Bohlin,
R.; Kurucz, R. L.; Riess, A. G.; Pelton, R.; Deustua, S. E.; Dixon,
W. V.; Sahnow, D. J.; Benford, D. J.; Gardner, J. P.; Feldman, P. D.;
Moos, H. W.; Lampton, M.; Perlmutter, S.; Woodgate, B. E.
2014AAS...22314918K Altcode:
Systematic errors associated with astrophysical data used to probe
fundamental astrophysical questions, such as SNeIa observations used
to constrain dark energy theories, are now rivaling and exceeding
the statistical errors associated with these measurements. ACCESS:
Absolute Color Calibration Experiment for Standard Stars is a series of
rocket-borne sub-orbital missions and ground-based experiments designed
to enable improvements in the precision of the astrophysical flux scale
through the transfer of absolute laboratory detector standards from
the National Institute of Standards and Technology (NIST) to a network
of stellar standards with a calibration accuracy of 1% and a spectral
resolving power of 500 across the 0.35 - 1.7μm bandpass. Achieving
this level of accuracy requires characterization and stability of the
instrument and detector including a thermal background that contributes
less than 1% to the flux per resolution element in the NIR. We will
present the instrument and calibration status with a focus on the
thermal mechanical design and associated performance data. The detector
control and performance will be presented in a companion poster (Morris,
et al). NASA APRA sounding rocket grant NNX08AI65G supports this work.

---------------------------------------------------------
Title: How to Build a Model of the Atmosphere and Spectrum
Authors: Kurucz, Robert L.
2014dapb.book...25K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Problems with Atomic and Molecular Data: Including All
the Lines
Authors: Kurucz, Robert L.
2014dapb.book...63K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: ACCESS: Detector Control and Performance
Authors: Morris, Matthew J.; Kaiser, M.; McCandliss, S. R.; Rauscher,
B. J.; Kimble, R. A.; Kruk, J. W.; Wright, E. L.; Bohlin, R.; Kurucz,
R. L.; Riess, A. G.; Pelton, R.; Deustua, S. E.; Dixon, W. V.; Sahnow,
D. J.; Mott, D. B.; Wen, Y.; Benford, D. J.; Gardner, J. P.; Feldman,
P. D.; Moos, H. W.; Lampton, M.; Perlmutter, S.; Woodgate, B. E.
2014AAS...22314917M Altcode:
ACCESS, Absolute Color Calibration Experiment for Standard Stars,
is a series of rocket-borne sub-orbital missions and ground-based
experiments that will enable improvements in the precision of the
astrophysical flux scale through the transfer of absolute laboratory
detector standards from the National Institute of Standards and
Technology (NIST) to a network of stellar standards with a calibration
accuracy of 1% and a spectral resolving power of 500 across the 0.35
to 1.7 micron bandpass (companion poster, Kaiser et al.). The flight
detector and detector spare have been selected and integrated with
their electronics and flight mount. The controller electronics have been
flight qualified. Vibration testing to launch loads and thermal vacuum
testing of the detector, mount, and housing have been successfully
performed. Further improvements to the flight controller housing have
been made. A cryogenic ground test system has been built. Dark current
and read noise tests have been performed, yielding results consistent
with the initial characterization tests of the detector performed
by Goddard Space Flight Center’s Detector Characterization Lab
(DCL). Detector control software has been developed and implemented
for ground testing. Performance and integration of the detector and
controller with the flight software will be presented. NASA APRA
sounding rocket grant NNX08AI65G supports this work.

---------------------------------------------------------
Title: ATLAS12: Opacity sampling model atmosphere program
Authors: Kurucz, Robert L.
2013ascl.soft03024K Altcode:
ATLAS12 is an opacity sampling model atmosphere program to
allow computation of models with individual abundances using line
data. ATLAS12 is able to compute the same models as ATLAS9 which uses
pretabulated opacities, plus models with arbitrary abundances. ATLAS12
sampled fluxes are quite accurate for predicting the total flux except
in the intermediate or narrow bandpass intervals because the sample
size is too small.

---------------------------------------------------------
Title: ACCESS: Design, Strategy, and Test Performance
Authors: Kaiser, Mary Elizabeth; Morris, M. J.; McCandliss, S. R.;
Rauscher, B. J.; Kimble, R. A.; Kruk, J. W.; Wright, E. L.; Pelton,
R. S.; Feldman, P. D.; Moos, H. W.; Riess, A. G.; Benford, D. J.;
Foltz, R.; Gardner, J. P.; Mott, D. B.; Wen, Y.; Woodgate, B. E.;
Bohlin, R.; Deustua, S. E.; Dixon, W. V.; Sahnow, D. J.; Kurucz,
R. L.; Lampton, M.; Perlmutter, S.
2013AAS...22135008K Altcode:
Improvements in the astrophysical flux scale are needed to answer
fundamental scientific questions ranging from cosmology to stellar
physics. In particular, the precise calibration of the flux scale across
the visible-NIR bandpass is fundamental to the precise determination
of dark energy parameters based on SNeIa photometry. ACCESS, Absolute
Color Calibration Experiment for Standard Stars, is a series of
rocket-borne sub-orbital missions and ground-based experiments that
will enable improvements in the precision of the astrophysical flux
scale through the transfer of absolute laboratory detector standards
from the National Institute of Standards and Technology (NIST) to
a network of stellar standards with a calibration accuracy of 1%
and a spectral resolving power of 500 across the 0.35 to 1.7 micron
bandpass. The telescope is a Dall-Kirkham Cassegrain with a 15.5-inch
primary. The spectrograph is a Rowland circle design, with the grating
operating as a low order (m=1-4) echelle, a Fery prism provides cross
dispersion, and a HST/WFC3 heritage HAWAII-1R HgCdTe detector is used
across the full spectral bandpass. The telescope mirrors have received
their flight coatings. The flight detector and detector spare have been
integrated with their electronics and flight mount. The controller
electronics have been flight qualified. Vibration testing to launch
loads and thermal vacuum testing of the detector, mount, and housing
have been performed. Detector characterization testing is in progress
(Morris et al.). Fabrication, integration, and automation of the
ground-based calibration subsystems are also in progress. The ACCESS
design, calibration strategy, and ground-based integration and test
results will be presented. Launch is expected this year. NASA sounding
rocket grant NNX08AI65G and DOE DE-FG02-07ER41506 support this work.

---------------------------------------------------------
Title: ACCESS: Detector Performance
Authors: Morris, Matthew J.; Kaiser, M.; Rauscher, B. J.; Kimble,
R. A.; Kruk, J. W.; Mott, D. B.; Wen, Y.; Foltz, R.; McCandliss, S. R.;
Pelton, R. S.; Wright, E. L.; Feldman, P. D.; Moos, H. W.; Riess,
A. G.; Benford, D. J.; Gardner, J. P.; Woodgate, B. E.; Bohlin, R.;
Deustua, S. E.; Dixon, W. V.; Sahnow, D. J.; Kurucz, R. L.; Lampton,
M.; Perlmutter, S.
2013AAS...22135007M Altcode:
ACCESS, Absolute Color Calibration Experiment for Standard Stars, is a
series of rocket-borne sub-orbital missions and ground-based experiments
that will enable improvements in the precision of the astrophysical flux
scale through the transfer of absolute laboratory detector standards
from the National Institute of Standards and Technology (NIST) to
a network of stellar standards with a calibration accuracy of 1%
and a spectral resolving power of 500 across the 0.35 to 1.7 micron
bandpass (overview Kaiser et al.). The flight detector and detector
spare have been integrated with their electronics and flight mount. The
controller electronics have been flight qualified. Vibration testing
to launch loads and thermal vacuum testing of the detector, mount,
and housing have been performed. The flight detector controller boards
have been installed into a ruggedized flight housing. They have been
successfully vacuum tested for periods significantly longer than the
flight length, and components have been heat-sunk and reinforced
as necessary. Thermal stability tests have been performed, and
results will be presented. Goddard Space Flight Center’s Detector
Characterization Lab (DCL) executed initial characterization tests for
the flight detector in 2007. These were repeated in 2012, to ensure and
establish baseline performance. Current lab characterization tests at
Johns Hopkins are ongoing, and results will be presented. NASA sounding
rocket grant NNX08AI65G supports this work.

---------------------------------------------------------
Title: ACCESS: design and sub-system performance
Authors: Kaiser, Mary Elizabeth; Morris, Matthew J.; McCandliss,
Stephan R.; Rauscher, Bernard J.; Kimble, Randy A.; Kruk, Jeffrey W.;
Pelton, Russell; Mott, D. B.; Wen, Yiting; Foltz, Roger; Quijada,
Manuel A.; Gum, Jeffery S.; Gardner, Jonathan P.; Kahle, Duncan M.;
Benford, Dominic J.; Woodgate, Bruce E.; Wright, Edward L.; Feldman,
Paul D.; Hart, Murdock; Moos, H. Warren; Riess, Adam G.; Bohlin,
Ralph; Deustua, Susana E.; Dixon, W. V.; Sahnow, David J.; Kurucz,
Robert; Lampton, Michael; Perlmutter, Saul
2012SPIE.8442E..46K Altcode:
Establishing improved spectrophotometric standards is important for
a broad range of missions and is relevant to many astrophysical
problems. ACCESS, “Absolute Color Calibration Experiment for
Standard Stars”, is a series of rocket-borne sub-orbital missions
and ground-based experiments designed to enable improvements in the
precision of the astrophysical flux scale through the transfer of
absolute laboratory detector standards from the National Institute
of Standards and Technology (NIST) to a network of stellar standards
with a calibration accuracy of 1% and a spectral resolving power of
500 across the 0.35-1.7µm bandpass.

---------------------------------------------------------
Title: DASCH Discovery of a Possible Nova-like Outburst in a Peculiar
Symbiotic Binary
Authors: Tang, Sumin; Grindlay, Jonathan E.; Moe, Maxwell; Orosz,
Jerome A.; Kurucz, Robert L.; Quinn, Samuel N.; Servillat, Mathieu
2012ApJ...751...99T Altcode: 2011arXiv1110.0019T
We present photometric and spectroscopic observations of a peculiar
variable (designated DASCH J075731.1+201735 or J0757) discovered from
our DASCH project using the digitized Harvard College Observatory
archival photographic plates. It brightened by about 1.5 mag in B
within a year starting in 1942, and then slowly faded back to its
pre-outburst brightness from 1943 to 1950s. The mean brightness level
was stable before and after the outburst, and ellipsoidal variations
with a period of P = 119.18 ± 0.07 days are seen, suggesting that the
star is tidally distorted. Radial-velocity measurements indicate that
the orbit is nearly circular (e = 0.02 ± 0.01) with a spectroscopic
period that is the same as the photometric period. The binary consists
of a 1.1 ± 0.3 M ⊙ M0III star, and a 0.6 ± 0.2 M
⊙ companion, very likely a white dwarf (WD). Unlike
other symbiotic binaries, there is no sign of emission lines or a
stellar wind in the spectra. With an outburst timescale of ~10 years
and estimated B-band peak luminosity MB ~ 0.7, J0757 is
different from any other known classic or symbiotic novae. The most
probable explanation of the outburst is hydrogen shell burning on the
WD, although an accretion-powered flare cannot be ruled out.

---------------------------------------------------------
Title: Division IX / Commission 25 / Working Group Infrared Astronomy
Authors: Milone, Eugene F.; Young, Andrew T.; Bell, Roger A.; Bessell,
Michael; Boyl, Richard P.; Carter, Brian; Clark, T. Alan; Cohen,
Martin; Fry, David J. I.; Garrison, Robert; Glass, Ian S.; Graham,
John; Granada, Anahi; Hillenbrand, Lynn; Kurucz, Robert L.; McLean,
Ian; Mountain, Matthew; Riecke, George; Riffel, Rogerio; Samec, Ronald
G.; Schiller, Stephen J.; Simons, Douglas; Skrutskie, Michael; Stagg,
C. Russell; Sterken, Christiaan L.; Thompson, Roger I.; Tokunaga,
Alan; Volk, Kevin; Wing, Robert
2012IAUTA..28..297M Altcode:
The formal commissioning of the IRWG occurred at the 1991 Buenos Aires
General Assembly, following a Joint Commission meeting at the IAU GA
in Baltimore in 1988 that identified the problems with ground-based
infrared photometry. The meeting justification, papers, and conclusions,
can be found in Milone (1989). In summary, the challenges involved
how to explain the failure to achieve the milli-magnitude precision
expected of infrared photometry and an apparent 3% limit on system
transformability. The proposed solution was to redefine the broadband
Johnson system, the passbands of which had proven so unsatisfactory
that over time effectively different systems proliferated, although
bearing the same “JHKLMNQ” designations; the new system needed to be
better positioned and centered in the spectral windows of the Earth's
atmosphere, and the variable water vapour content of the atmosphere
needed to be measured in real time to better correct for atmospheric
extinction.

---------------------------------------------------------
Title: Iron abundance in the prototype PG 1159 star, GW Vir pulsator
PG 1159 - 035, and related objects
Authors: Werner, K.; Rauch, T.; Kruk, J. W.; Kurucz, R. L.
2011A&A...531A.146W Altcode: 2011arXiv1105.5276W
We performed an iron abundance determination of the hot, hydrogen
deficient post-AGB star PG 1159 - 035, which is the prototype of
the PG 1159 spectral class and the GW Vir pulsators, and of two
related objects (PG 1520 + 525, PG 1144 + 005), based on the first
detection of Fe viii lines in stellar photospheres. In another PG
1159 star, PG 1424 + 535, we detect Fe vii lines. In all four stars,
each within Teff = 110 000-150 000 K, we find a solar iron
abundance. This result agrees with our recent abundance analysis of
the hottest PG 1159 stars (Teff = 150 000-200 000 K) that
exhibit Fe x lines. On the whole, we find that the PG 1159 stars are
not significantly iron deficient, in contrast to previous notions. Based on observations made with the NASA-CNES-CSA Far Ultraviolet
Spectroscopic Explorer. FUSE was operated for NASA by the Johns Hopkins
University under NASA contract NAS5-32985. Based on observations with
the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope
Science Institute, which is operated by the Association of Universities
for Research in Astronomy, Inc., under NASA contract NAS5-26666.

---------------------------------------------------------
Title: Including all the lines
Authors: Kurucz, Robert L.
2011CaJPh..89..417K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: ACCESS: Mission Overview, Fabrication Status, and Preliminary
Performance
Authors: Kaiser, Mary Elizabeth; McCandliss, S. R.; Sahnow, D. J.;
Dixon, W. V.; Feldman, P. D.; Gaither, B. W.; Moos, H. W.; Pelton,
R. S.; Riess, A. G.; Rauscher, B. J.; Kimble, R. A.; Kruk, J. W.;
Benford, D. J.; Gardner, J. P.; Hill, R. J.; Kahle, D. M.; Mott,
D. B.; Waczynski, A.; Wen, Y.; Woodgate, B. E.; Bohlin, R. C.; Deustua,
S. E.; Kurucz, R.; Lampton, M.; Perlmutter, S.; Wright, E. L.
2011AAS...21725412K Altcode: 2011BAAS...4325412K
Improvements in the precision of the astrophysical flux scale are
needed to answer fundamental scientific questions ranging from
cosmology to stellar physics. ACCESS - Absolute Color Calibration
Experiment for Standard Stars (Kaiser et al., 2009) is a sub-orbital
program with a rocket-borne payload that will enable the transfer
of absolute laboratory detector standards from NIST to a network of
stellar standards with a calibration accuracy of 1% and a spectral
resolving power of R = 500 across the 0.35-1.7 micron bandpass. The
ACCESS flight detector has been selected and initial tests have been
performed. The detector flight electronics are being fabricated. The
optical system fabrication is in progress. The ground calibration
system fabrication and component testing has begun. The cornerstone
of the ground calibration system is the artificial star system that
will be used to transfer the NIST photodiode detector standards to the
telescope payload and hence the stars. First flight is anticipated for
late 2011 from White Sands Missile Range. We will present the instrument
overview, status of the instrument fabrication, and the calibration
and observation strategy. Support for this work was provided by NASA
through grant NNX08AI65G and DOE through grant DE-FG02-07ER41506.

---------------------------------------------------------
Title: New Fe ii energy levels from stellar spectra
Authors: Castelli, F.; Kurucz, R. L.
2010A&A...520A..57C Altcode: 2010arXiv1006.5606C
 Aims: The spectra of B-type and early A-type stars show
numerous unidentified lines in the whole optical range, especially in
the 5100-5400 Å interval. Because Fe ii transitions to high energy
levels should be observed in this region, we used semiempirical
predicted wavelengths and gf-values of Fe ii to identify unknown
lines. Methods: Semiempirical line data for Fe ii computed
by Kurucz are used to synthesize the spectrum of the slow-rotating,
Fe-overabundant CP star HR 6000. Results: We determined a
total of 109 new 4f levels for Fe ii with energies ranging from
122 324 cm-1 to 128 110 cm-1. They belong
to the Fe ii subconfigurations 3d6(3P)4f
(10 levels), 3d6(3H)4f (36
levels), 3d6(3F)4f (37 levels), and
3d6(3G)4f (26 levels). We also found 14
even levels from 4d (3 levels), 5d (7 levels), and 6d (4 levels)
configurations. The new levels have allowed us to identify more
than 50% of the previously unidentified lines of HR 6000 in the
wavelength region 3800-8000 Å. Tables listing the new energy levels
are given in the paper; tables listing the spectral lines with
log gf ≥ -1.5 that are transitions to the 4f energy levels are
given in the Online Material. These new levels produce 18 000 lines
throughout the spectrum from the ultraviolet to the infrared. Tables 6-9 are also available in electronic form at the CDS
via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/520/A57">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/520/A57</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: New FeII energy levels from
stellar spectra (Castelli+, 2010)
Authors: Castelli, F.; Kurucz, R. L.
2010yCat..35200057C Altcode: 2010yCat..35209057C
FeII lines in the 3800-8000Å region, produced by transitions to
the FeII subconfigurations (3P)4f, (3H)4f,
(3F)4f, and (3G)4f are given in Tables 6, 7, 8,
and 9, respectively. Only lines with loggf&gt;=-1.5 are listed. Most of
these lines can be observed in the UVES spectrum of HR 6000 and have
allowed us to identify more than 50% of the previously unidentified
lines (Castelli &amp; Hubrig, 2007A&amp;A...475.1041C). (4
data files).

---------------------------------------------------------
Title: ACCESS: design and preliminary performance
Authors: Kaiser, Mary Elizabeth; Kruk, Jeffrey W.; McCandliss,
Stephan R.; Rauscher, Bernard J.; Kimble, Randy A.; Pelton, Russell
S.; Sahnow, David J.; Dixon, W. V.; Feldman, Paul D.; Gaither, Bryan
W.; Lazear, Justin S.; Moos, H. Warren; Riess, Adam G.; Benford,
Dominic J.; Gardner, Jonathan P.; Hill, Robert J.; Kahle, Duncan M.;
Mott, D. Brent; Waczynski, Augustyn; Wen, Yiting; Woodgate, Bruce
E.; Bohlin, Ralph C.; Deustua, Susana E.; Kurucz, Robert; Lampton,
Michael; Perlmutter, Saul; Wright, Edward L.
2010SPIE.7731E..3IK Altcode: 2010SPIE.7731E.112K
ACCESS, Absolute Color Calibration Experiment for Standard Stars, is a
series of rocket-borne sub-orbital missions and ground-based experiments
designed to enable improvements in the precision of the astrophysical
flux scale through the transfer of absolute laboratory detector
standards from the National Institute of Standards and Technology
(NIST) to a network of stellar standards with a calibration accuracy
of 1% and a spectral resolving power of 500 across the 0.35.1.7μm
bandpass. Establishing improved spectrophotometric standards is
important for a broad range of missions and is relevant to many
astrophysical problems. Systematic errors associated with problems such
as dark energy now compete with the statistical errors and thus limit
our ability to answer fundamental questions in astrophysics. The ACCESS
design, calibration strategy, and an updated preliminary performance
estimate are discussed.

---------------------------------------------------------
Title: ACCESS: Mission Overview, Design and Status
Authors: Kaiser, Mary Elizabeth; McCandliss, Stephan R.; Pelton,
Russell; Sahnow, David; Dixon, W. V.; Feldman, Paul D.; Gaither,
Bryan W.; Lazear, Justin S.; Moos, H. Warren; Riess, Adam; Rauscher,
Bernard J.; Kruk, Jeffrey W.; Kimble, Randy A.; Benford, Dominic J.;
Foltz, Roger; Gardner, Jonathan P.; Hill, Robert J.; Kahle, Duncan M.;
Malumuth, Eliot; Mott, D. Brent; Waczynski, Augustyn; Wen, Yiting;
Woodgate, Bruce E.; Bohlin, Ralph C.; Deustua, Susana; Kurucz, Robert;
Lampton, Michael; Perlmutter, Saul; Wright, Edward L.
2010hstc.workE..10K Altcode:
ACCESS, Absolute Color Calibration Experiment for Standard Stars, is a
series of rocket-borne sub-orbital missions and ground-based experiments
designed to enable improvements in the precision of the astrophysical
flux scale through the transfer of absolute laboratory detector
standards from the National Institute of Standards and Technology
(NIST) to a network of stellar standards with a calibration accuracy
of 1% and a spectral resolving power of 500 across the 0.35-1.7
μm bandpass. Establishing improved spectrophotometric standards
is important for a broad range of missions and is relevant to many
astrophysical problems. Systematic errors associated with problems such
as dark energy now compete with the statistical errors and thus limit
our ability to answer fundamental questions in astrophysics. The ACCESS
payload and ground calibration components currently span a range of
readiness levels extending from the design phase, through procurement,
fabrication, and component test phases. The strategy for achieving
a &lt;1% spectrophotometric calibration accuracy, a description and
status of the instrument and the ground calibration system, and the
NIST traceability components are discussed.

---------------------------------------------------------
Title: New Fe II energy levels from stellar spectra
Authors: Castelli, Fiorella; Kurucz, Robert L.
2010arXiv1007.1552C Altcode:
The spectra of B-type and early A-type stars show mumerous unidentified
lines in the whole optical range, especially in the 5100-5400 A
interval. Because Fe II transitions to high energy levels should be
observed in this region, we used semiempirical predicted wavelengths
and gf-values of Fe II to identify unknown lines. Semiempirical
line data for Fe II computed by Kurucz are used to synthesize the
spectrum of the slow-rotating, Fe-overabundant CP star HR 6000. We
determined a total of 109 new 4f levels for Fe II with energies
ranging from 122324 cm^-1 to 128110 cm^-1. They belong to the Fe II
subconfigurations 3d^6(^3P)4f (10 levels), 3d^6(^3H)4f (36 levels),
3d^6(^3F)4f (37 levels), and 3d^6(^3G)4f (26 levels). We also found
14 even levels from 4d (3 levels), 5d (7 levels), and 6d (4 levels)
configurations. The new levels have allowed us to identify more than
50% of the previously unidentified lines of HR 6000 in the wavelength
region 3800-8000 A. Tables listing the new energy levels are given
in the paper; tables listing the spectral lines with log gf &gt;/=
-1.5 that are transitions to the 4f energy levels are given in the
Online Material. These new levels produce 18000 lines throughout the
spectrum from the ultraviolet to the infrared.

---------------------------------------------------------
Title: An improved high-resolution solar reference spectrum for
earth's atmosphere measurements in the ultraviolet, visible, and
near infrared
Authors: Chance, K.; Kurucz, R. L.
2010JQSRT.111.1289C Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Division IX / Commission 25 / Working Group: Infrared Astronomy
Authors: Milone, Eugene F.; Young, Andrew T.; Bell, Roger A.; Bessell,
Michael; Boyl, Richard P.; Cohen, Martin; Fry, David J. I.; Garrison,
Robert; Garrison, Robert; Glass, Ian S.; Graham, John; Granada,
Anahi; Hillenbrand, Lynn; Kurucz, Robert L.; McLean, Ian; Mountain,
Matthew; Riecke, George; Riffel, Rogerio; Samec, Ronald G.; Schiller,
Stephen J.; Simons, Douglas; Skrutskie, Michael; Stagg, C. Russell;
Sterken, Christiaan L.; Thompson, Roger I.; Tokunaga, Alan; Volk,
Kevin; Wing, Robert
2010IAUTB..27..229M Altcode:
The formal origin of the IRWG occured at the Buenos Aires General
Assembly, following a Joint Commission meeting at the IAU GA in
Baltimore in 1988 that identified the problems with ground-based
infrared photometry. The situation is summarized in Milone (1989). In
short, the challenges involved how to explain the failure to achieve
the milli-magnitude precision expected of infrared photometry and an
apparent 3% limit on system transformability. The proposed solution
was to redefine the broadband Johnson system, the passbands of which
had proven so unsatisfactory that over time effectively different
systems proliferated, although bearing the same JHKLMNQ designations;
the new system needed to be better positioned and centered in the
atmospheric windows of the Earth's atmosphere, and the variable water
vapour content of the atmosphere needed to be measured in real time
to better correct for atmospheric extinction.

---------------------------------------------------------
Title: Biological damage due to photospheric, chromospheric and
flare radiation in the environments of main-sequence stars
Authors: Cuntz, Manfred; Guinan, Edward F.; Kurucz, Robert L.
2010IAUS..264..419C Altcode: 2009arXiv0911.1982C
We explore the biological damage initiated in the environments of F, G,
K, and M-type main-sequence stars due to photospheric, chromospheric
and flare radiation. The amount of chromospheric radiation is, in
a statistical sense, directly coupled to the stellar age as well
as the presence of significant stellar magnetic fields and dynamo
activity. With respect to photospheric radiation, we also consider
detailed synthetic models, taking into account millions or hundred of
millions of lines for atoms and molecules. Chromospheric UV radiation is
increased in young stars in regard to all stellar spectral types. Flare
activity is most pronounced in K and M-type stars, which also has the
potential of stripping the planetary atmospheres of close-in planets,
including planets located in the stellar habitable zone. For our
studies, we take DNA as a proxy for carbon-based macromolecules,
guided by the paradigm that carbon might constitute the biochemical
centerpiece of extraterrestrial life forms. Planetary atmospheric
attenuation is considered in an approximate manner.

---------------------------------------------------------
Title: ACCESS: Enabling an Improved Flux Scale for Astrophysics
Authors: Kaiser, Mary Elizabeth; Kruk, J. W.; McCandliss, S. R.;
Sahnow, D. J.; Rauscher, B. J.; Kimble, R. A.; Wright, E. L.;
Dixon, W. V.; Feldman, P. D.; Moos, H. W.; Reiss, A. G.; Pelton,
R. S.; Gaither, B. W.; Benford, D. J.; Gardner, J. P.; Hill, R. J.;
Woodgate, B. E.; Bohlin, R. C.; Deustua, S. E.; Kurucz, R.; Lampton,
M.; Perlmutter, S.
2010AAS...21544119K Altcode: 2010BAAS...42..404K
Improvements in the precision of the astrophysical flux scale are needed
to answer fundamental scientific questions ranging from cosmology
to stellar physics. In particular, the precise calibration of the
flux scale across the bandpass extending from 0.35 - 1.7 microns is
fundamental to the precise determination of dark energy parameters based
on SNeIa photometry. ACCESS - Absolute Color Calibration Experiment
for Standard Stars (Kaiser et al., 2009) is a rocket-borne payload that
will enable the transfer of absolute laboratory detector standards from
NIST to a network of stellar standards with a calibration accuracy
of 1% and a spectral resolving power of R = 500 across the 0.35-1.7
micron bandpass. Among the strategies being employed to minimize
calibration uncertainties are: (1) judicious selection of standard
stars (previous calibration heritage, minimal spectral features, robust
stellar atmosphere models), (2) execution of observations above the
Earth's atmosphere (eliminates atmospheric contamination of the stellar
spectrum), (3) a single optical path and detector (to minimize visible
to NIR cross-calibration uncertainties), (4) establishment of an a
priori error budget, (5) on-board monitoring of instrument performance,
and (6) fitting stellar atmosphere models to the data to search for
discrepancies and enable extrapolation to wavelengths outside the ACCESS
bandpass. The instrument design, calibration and observing strategy
will be presented. Support for this work was provided by NASA
through grant NNX08AI65G and DOE through grant DE-FG02-07ER41506.

---------------------------------------------------------
Title: A New View of Vega's Composition, Mass, and Age
Authors: Yoon, Jinmi; Peterson, Deane M.; Kurucz, Robert L.; Zagarello,
Robert J.
2010ApJ...708...71Y Altcode:
We present estimates of Vega's composition, mass, and age based on a
simultaneous fit of high-resolution metal line profiles, the wings
of the Balmer lines, the absolute visible/near-IR fluxes, and high
angular resolution triple phase data from the Navy Prototype Optical
Interferometer to gravity-darkened Roche models. This substantially
expands our earlier analysis. We determine that Vega has a much lower
mass, 2.135 ± 0.074 M sun, than generally assumed. This
strongly supports the contention that Vega is metal-poor throughout
(Z ~ 0.008), suggesting it was formed that way. Assuming a uniform
composition equal to that derived for the surface, and the luminosity
and radius obtained here, we derive a best estimate of Vega's age,
455 ± 13 Myr, and mass, 2.157 ± 0.017 M sun, by fitting
to standard isochrones. We continue to argue that Vega is much too old
to be coeval with other members of the Castor moving group and is thus
unlikely to be a member. The updated chemical abundances continue to
support the conclusion that Vega is a λ Boo star.

---------------------------------------------------------
Title: ACCESS: Enabling an Improved Flux Scale for Astrophysics
Authors: Kaiser, Mary Elizabeth; Kruk, Jeffrey W.; McCandliss, Stephan
R.; Sahnow, David J.; Barkhouser, Robert H.; Van Dixon, W.; Feldman,
Paul D.; Moos, H. Warren; Orndorff, Joseph; Pelton, Russell; Riess,
Adam G.; Rauscher, Bernard J.; Kimble, Randy A.; Benford, Dominic J.;
Gardner, Jonathan P.; Hill, Robert J.; Woodgate, Bruce E.; Bohlin,
Ralph C.; Deustua, Susana E.; Kurucz, Robert; Lampton, Michael;
Perlmutter, Saul; Wright, Edward L.
2010arXiv1001.3925K Altcode:
Improvements in the precision of the astrophysical flux scale are needed
to answer fundamental scientific questions ranging from cosmology to
stellar physics. The unexpected discovery that the expansion of the
universe is accelerating was based upon the measurement of astrophysical
standard candles that appeared fainter than expected. To characterize
the underlying physical mechanism of the "Dark Energy" responsible
for this phenomenon requires an improvement in the visible-NIR flux
calibration of astrophysical sources to 1% precision. These improvements
will also enable large surveys of white dwarf stars, e.g. GAIA, to
advance stellar astrophysics by testing and providing constraints for
the mass-radius relationship of these stars. ACCESS (Absolute Color
Calibration Experiment for Standard Stars) is a rocket-borne payload
that will enable the transfer of absolute laboratory detector standards
from NIST to a network of stellar standards with a calibration accuracy
of 1% and a spectral resolving power of R = 500 across the 0.35-1.7
micron bandpass. Among the strategies being employed to minimize
calibration uncertainties are: (1) judicious selection of standard
stars (previous calibration heritage, minimal spectral features,
robust stellar atmosphere models), (2) execution of observations
above the Earth's atmosphere (eliminates atmospheric contamination
of the stellar spectrum), (3) a single optical path and detector
(to minimize visible to NIR cross-calibration uncertainties), (4)
establishment of an a priori error budget, (5) on-board monitoring of
instrument performance, and (6) fitting stellar atmosphere models to
the data to search for discrepancies and confirm performance.

---------------------------------------------------------
Title: New identified (^3H)4d-(^3H)4f transitions of Fe II from UVES
spectra of HR 6000 and 46 Aquilae
Authors: Castelli, F.; Kurucz, R.; Hubrig, S.
2009A&A...508..401C Altcode: 2009arXiv0909.1936C
Aims. The analysis of the high-resolution UVES spectra of the CP
stars HR 6000 and 46 Aql has revealed the presence of an impressive
number of unidentified lines, in particular in the 5000-5400 Å
region. Because numerous 4d-4f transitions of FeII lie in this
spectral range, and because both stars are iron overabundant, we
investigate whether the unidentified lines are FeII. Methods:
ATLAS12 model atmospheres with parameters T_eff = 13 450 K, log g =
4.3 and T_eff = 12 560 K, log g = 3.8 were computed for the individual
abundances of the stars HR 6000 and 46 Aql, respectively, to use them
as spectroscopic sources to identify FeII lines and determine FeII
gf-values. After identifying several unknown lines in the stellar
spectra as (3H)4d-(3H)4f transitions of FeII,
we derived astrophysical log gf-values for them. The energies of
the upper levels were assigned on the basis of both laboratory iron
spectra and predicted energy levels. Results: We determined
21 new levels of FeII with energies between 122 910.9 cm-1
and 123 441.1 cm-1. They allowed us to add 1700 new lines
to the FeII linelist in the wavelength range 810-15 011 Å. Many of
these lines are sufficiently strong to contribute to the spectra of
Population I late B-type stars, even when their iron abundance is
subsolar. In the 5000-6000 Å region discussed in this paper, the
astrophysical and computed log gf-values show good general agreement
and greatly improve the synthetic spectrum of both HR 6000 and 46
Aql. However, many features remain unidentified indicating that further
work to classify FeII high energy levels has still to be done This study is the result of a collaboration with Sveneric Johansson,
who unfortunately died before this paper started to be written. Tables 4-6, and Appendices A and B are only available in electronic
form at http://www.aanda.org

---------------------------------------------------------
Title: Astrobiology in the Environments of Main-Sequence Stars:
Effects of Photospheric Radiation
Authors: Cuntz, M.; Gurdemir, L.; Guinan, E. F.; Kurucz, R. L.
2009ASPC..420..253C Altcode: 2007arXiv0712.3260C
We explore if carbon-based macromolecules (such as DNA) in the
environments of stars other than the Sun are able to survive the effects
of photospheric stellar radiation, such as UV-C. Therefore, we focus
on main-sequence stars of spectral types F, G, K, and M. Emphasis
is placed on investigating the radiative environment in the stellar
habitable zones. Stellar habitable zones are relevant to astrobiology
because they constitute circumstellar regions in which a planet of
suitable size can maintain surface temperatures for water to exist in
fluid form, thus increasing the likelihood of Earth-type life.

---------------------------------------------------------
Title: Including All the Lines
Authors: Kurucz, Robert L.
2009AIPC.1171...43K Altcode: 2009arXiv0912.5371K
I present a progress report on including all the lines in the linelists,
including all the lines in the opacities, including all the lines in
the model atmosphere and spectrum synthesis calculations, producing
high-resolution, high-signal-to-noise atlases that show (not quite)
all the lines, so that finally we can determine the properties of
stars from a few of the lines.

---------------------------------------------------------
Title: New extended atomic data in cool star model atmospheres. Using
Kurucz's new iron data in MAFAGS-OS models
Authors: Grupp, F.; Kurucz, R. L.; Tan, K.
2009A&A...503..177G Altcode: 2009arXiv0906.5449G
Context: Cool star model atmospheres are a common tool for the
investigation of stellar masses, ages and elemental abundance
composition. Theoretical atmospheric models strongly depend on the
atomic data used when calculating them. Aims: We present the
changes in flux and temperature stratification when changing from iron
data computed by R.L. Kurucz in the mid 90s to the Kurucz 2009 iron
computations. Methods: MAFAGS-OS opacity sampling atmospheres
were recomputed with Kurucz 2009 iron atomic data as implemented in the
VALD database by Ryabchikova. Temperature stratification and emergent
flux distribution of the new version, called MAFAGS-OS9, is compared
to the former version and to solar flux measurements. Results:
Using the Kurucz line lists converted into the VALD format and new
bound-free opacities for Mg i and Al i leads to changes in the solar
temperature stratification by not more than 28 K. At the same time,
the calculated solar flux distribution shows significantly better
agreement between observations and theoretical solar models. These
changes in the temperature stratification of the corresponding models
are small, but nevertheless of a magnitude that affects stellar
parameter determinations and abundance analysis.

---------------------------------------------------------
Title: ACCESS - Absolute Color Calibration Experiment for Standard
Stars
Authors: Kaiser, Mary Elizabeth; Kruk, J. W.; McCandliss, S. R.;
Sahnow, D. J.; Dixon, W. V.; Feldman, P. D.; Moos, H.; Riess, A. G.;
Rauscher, B. J.; Kimble, R. A.; Benford, D. J.; Gardner, J. P.;
Woodgate, B. E.; Bohlin, R. C.; Duestua, S. E.; Kurucz, R.; Lampton,
M.; Perlmutter, S.; Wright, E. L.
2009AAS...21347515K Altcode: 2009BAAS...41..437K
ACCESS is a rocket-borne payload with a ground-based calibration
and performance monitoring program. It is designed to transfer the
NIST absolute laboratory standards to the stars with a precision and
calibration accuracy of 1% at a spectral resolving power greater
than 500 across the 0.35-1.7 micron bandpass. This represents a
significant improvement in the absolute and relative astrophysical
flux calibration systems, especially at NIR wavelengths. Several
strategies will be employed to minimize calibration uncertainties. The
standard star sample is comprised of stars with previous calibration
heritage, minimal spectral features, and robust stellar atmosphere
models. Observations will be conducted above the Earth's atmosphere to
eliminate atmospheric contamination of the stellar spectrum. To
avoid calibration uncertainties between the visible and the NIR spectra,
a single optical path and detector will be used. An a priori error
budget will be established. Instrument performance will be tracked
through the use of an on-board calibration monitor. Each standard star
will be observed twice to establish repeatability. We will present the
instrument design, observing and calibration strategies and error budget
for ACCESS. Results of laboratory tests relevant to the design of the
on-board calibration monitor will also be presented. Establishing
improved spectrophotometric standards is important for a broad range of
missions and is relevant to many astrophysical problems. In particular,
the precise calibration of the flux scale across the bandpass extending
from 0.35 - 1.7 microns is fundamental to the precise determination
of dark energy parameters based on SNeIa photometry. Support
for this work was provided by NASA through grant NNX08AI65G and DOE
through grant DE-FG02-07ER41506.

---------------------------------------------------------
Title: Division IX / Commission 25 / Working Group Infrared Astronomy
Authors: Milone, Eugene F.; Young, Andrew T.; Bauwens, Eva; Bell,
Roger A.; Bessell, Michael S.; Cohen, Martin; Garrison, Robert;
Glass, Ian S.; Graham, John A.; Henden, Arne A.; Hensberge, Herman;
Hillenbrand, Lynne A.; Howell, Steve B.; Kidger, Mark R.; Kurucz,
Robert L.; Landolt, Arlo U.; McLean, Ian S.; Mountain, Matthew; Rieke,
George H.; Schiller, Stephen J.; Simons, Douglas A.; Skrutskie,
Michael F.; Stagg, C. Russell; Sterken, Christiaan L.; Thompson,
Roger I.; Tokunaga, Alan T.; Volk, Kevin
2009IAUTA..27..313M Altcode:
As we have noted before, the WG-IR was created following a Joint
Commission Meeting at the IAU General Assembly in Baltimore in 1988,
a meeting that provided both diagnosis and prescription for the
perceived ailments of infrared photometry at the time. The results were
summarized in Milone (1989). The challenges involve how to explain
the failure to systematically achieve the milli-magnitude precision
expected of infrared photometry and an apparent 3% limit on system
transformability. The proposed solution was to re-define the broadband
Johnson system, the passbands of which had proven so unsatisfactory
that over time effectively different systems proliferated although
bearing the same JHKLMNQ designations; the new system needed to be
better positioned and centered in the atmospheric windows of the
Earth's atmosphere, and the variable water vapour content of the
atmosphere needed to be measured in real time to better correct for
atmospheric extinction.

---------------------------------------------------------
Title: Most Population III Supernovae are Duds
Authors: Kurucz, Robert L.
2008arXiv0808.3282K Altcode:
One Population III dud supernova produces enough oxygen to enable ten
million solar masses of primordial gas to bind into M dwarfs. This is
possible because radiation from other Population III stars implodes
the mixture of oxygen ejecta and primordial gas into a globular
cluster. Model atmosphere calculations for oxygen dwarfs show that water
blocks most of the infrared flux. The flux is redistributed into the
visible to produce an unfamiliar, distinctive energy distribution. One
million dud supernovae in a large protogalaxy are sufficient to produce
the "dark matter" halo.

---------------------------------------------------------
Title: On-board calibration monitor for tracking instrument
sensitivity
Authors: Kruk, J. W.; Kaiser, M. E.; McCandliss, S. R.; Orndorff,
J.; Barkhouser, R. H.; Sahnow, D. J.; Benford, D. J.; Bohlin, R. C.;
Deustua, S. E.; Dixon, W. V.; Feldman, P. D.; Gardner, J. P.; Kimble,
R. A.; Kurucz, R.; Lampton, M.; Moos, H. W.; Perlmutter, S.; Rauscher,
B. J.; Riess, A. G.; Woodgate, B. E.; Wright, E. L.
2008SPIE.7014E..5JK Altcode: 2008SPIE.7014E.184K
The On-board Calibration Monitor (OCM) is being developed as an
integral component of the ACCESS instrument and as a pathfinder for
other missions. It provides stable full-aperture illumination of the
telescope for tracking the instrument sensitivity as a function of
time. The light source is composed of an ensemble of LED pairs with
central wavelengths that span the spectral range of the instrument
and illuminate a diffuser that is observed by the full optical
path. Feedback stabilization of the light source intensity is achieved
by photodiode monitoring of each LED. This stable source will provide
real time knowledge of the ACCESS sensitivity throughout the 5-year
duration of the program. The present status of the design and laboratory
evaluation of the OCM system will be presented.

---------------------------------------------------------
Title: ACCESS: absolute color calibration experiment for standard
stars
Authors: Kaiser, Mary Elizabeth; Kruk, Jeffrey W.; McCandliss,
Stephan R.; Sahnow, David J.; Rauscher, Bernard J.; Benford, Dominic
J.; Bohlin, Ralph C.; Deustua, S. E.; Dixon, W. V.; Feldman, P. D.;
Gardner, J. P.; Kimble, R. A.; Kurucz, R.; Lampton, M.; Moos, H. W.;
Perlmutter, S.; Riess, A. G.; Woodgate, B. E.; Wright, E. L.
2008SPIE.7014E..5YK Altcode: 2008SPIE.7014E.197K
ACCESS is a recently approved rocket-borne payload with a ground-based
calibration and performance monitoring program that is designed to
transfer the National Institute of Standards and Technology (NIST)
absolute laboratory standards to the stars with a precision and
calibration accuracy of 1% across the 0.35-1.7μm bandpass. This
represents a significant improvement in the absolute and relative
astrophysical flux calibration system, particularly at near-infrared
(NIR) wavelengths. Establishing improved spectrophotometric standards
is important for a broad range of missions and is relevant to many
astrophysical problems. In particular, the precise calibration of
the flux scale across the bandpass extending from 0.35-1.7 μm is
fundamental to the precise determination of dark energy measurements
based on SNeIa photometry.

---------------------------------------------------------
Title: Astrobiological effects of F, G, K and M main-sequence stars
Authors: Cuntz, M.; Gurdemir, L.; Guinan, E. F.; Kurucz, R. L.
2008IAUS..249..203C Altcode: 2007arXiv0712.3257C; 2007IAUS..249..203C
We focus on the astrobiological effects of photospheric radiation
produced by main-sequence stars of spectral types F, G, K, and M. The
photospheric radiation is represented by using realistic spectra, taking
into account millions or hundred of millions of lines for atoms and
molecules. DNA is taken as a proxy for carbon-based macromolecules,
assumed to be the chemical centerpiece of extraterrestrial life
forms. Emphasis is placed on the investigation of the radiative
environment in conservative as well as generalized habitable zones.

---------------------------------------------------------
Title: ACCESS - Absolute Color Calibration Experiment for Standard
Stars
Authors: Kaiser, Mary Elizabeth; Kruk, J. W.; McCandliss, S. R.;
Sahnow, D. J.; Dixon, W. V.; Feldman, P. D.; Moos, H. W.; Riess,
A. G.; Rauscher, B. J.; Benford, D. J.; Gardner, J. P.; Kimble, R. A.;
Woodgate, B. E.; Bohlin, R. C.; Kurucz, R.; Deustua, S. E.; Lampton,
M.; Perlmutter, S.; Wright, E. L.
2007AAS...211.1123K Altcode: 2007BAAS...39..748K
ACCESS is a recently approved series of rocket-borne sub-orbital
missions and ground-based experiments that will establish a network
of standard stars with absolute fluxes that are directly traceable to
ground based laboratory standards maintained by NIST. The goal of this
program is to establish a high-precision spectrophotometric calibration
system in the visible and near-infrared. An absolute spectrophotometric
calibration accuracy of &lt;1% will be achieved in the 0.35-1.7 micron
bandpass at a spectral resolution of greater than 500, which represents
a significant improvement in the absolute calibration in the NIR
bandpass. Standard star observations extending to 10th magnitude will
establish the first links in a chain of stellar calibrators. Measurement
of absolute fluxes of a small number of standard stars enables the
existing networks of standards to be placed on an improved absolute
scale and makes them available to all telescopes. ACCESS will
reduce uncertainties in the current standard star calibration system
by: (1) judicious selection of standard stars, (2) observing above the
Earth's atmosphere, (3) using a single optical path and detector, (4)
establishing an a priori error budget, (5) performing NIST traceable
sub-system and end-to-end payload calibrations, and (6) monitoring and
tracking payload performance. Having improved spectrophotometric
standards is important for a broad range of missions and is relevant
to many astrophysical problems. It is fundamental to the precise
determination of dark energy measurements using SNeIa photometry. In
addition, our understanding of stellar physics will be extended through
stellar atmosphere modeling of our target stars.

---------------------------------------------------------
Title: Division IX / Commission 25 / Working Group Infrared Astronomy
Authors: Milone, Eugene F.; Young, Andrew T.; Bell, Roger A.; Bessell,
Michael S.; Cohen, Martin; Garrison, Robert F.; Glass, Ian S.; Graham,
John A.; Hillenbrand, Lynne A.; Kurucz, Robert L.; Mountain, Matthew;
Rieke, George H.; Schiller, Stephen J.; Simons, Douglas A.; Skrutskie,
Michael F.; Stagg, C. Russell; Sterken, Christiaan L.; Thompson,
Roger I.; Tokunaga, Alan T.; Volk, Kevin; Volk
2007IAUTB..26..195M Altcode:
The WG-IR was created following a Joint Commission Meeting at the
IAU General Assembly in Baltimore in 1988, a meeting that provided
both diagnosis and prescription for the perceived ailments of
infrared photometry at the time. The results were summarized
in Milone (1989). The challenges involve how to explain the
failure to systematically achieve the milli-magnitude precision
expected of infrared photometry and an apparent 3% limit on system
transformability. The proposed solution was to redefine the broadband
Johnson system, the passbands of which had proven so unsatisfactory
that over time effectively different systems proliferated although
bearing the same JHKLMNQ designations; the new system needed to be
better positioned and centered in the atmospheric windows of the
Earth's atmosphere, and the variable water vapour content of the
atmosphere needed to be measured in real time to better correct for
atmospheric extinction.

---------------------------------------------------------
Title: ACCESS - Absolute Color Calibration Experiment for Standard
Stars
Authors: Kaiser, Mary Elizabeth; Kruk, J. W.; McCandliss, S. R.;
Sahnow, D. J.; Dixon, W.; Feldman, P. D.; Moos, H.; Riess, A.;
Rauscher, B. J.; Kimble, R. A.; Gardner, J. P.; Woodgate, B. E.;
Bohlin, R. C.; Deustua, S. E.; Kurucz, R.; Perlmutter, S.; Wright,
E. L.
2007AAS...20925403K Altcode: 2007BAAS...39..274K
ACCESS is a proposed series of rocket-borne sub-orbital missions whose
purpose is to establish a network of standard stars with absolute fluxes
that are directly traceable to ground based laboratory calibration
standards maintained by NIST. Our goal is to obtain an absolute
spectrophotometric calibration accuracy of &lt;1% in the 0.35-1.7
micron bandpass at a spectral resolution of greater than 500. This
represents a significant improvement in the absolute calibration in the
NIR bandpass. This fundamental astrophysics experiment will establish
the first links in a chain of stellar calibrators including standard
stars (10th magnitude) observable by major telescopes, thus enabling
the ultimate calibration to extend to faint magnitudes. This calibration
program is important for a broad range of missions and relevant to many
astrophysical problems. It is fundamental to photometrically based dark
energy missions which use supernova type Ia and will provide the first
steps in the calibration path required to support the determination of
brightness as a function of distance for SNIae. In addition, it will
enable improved stellar atmosphere models, furthering our understanding
of stellar physics.

---------------------------------------------------------
Title: Cryptoplanet update
Authors: Kurucz, Robert L.
2007arXiv0704.2860K Altcode:
We have had several talks recently reviewing 11 years of exoplanet
discoveries through radial velocity variations, or from transits, or
from microlensing. More than 200 exoplanets have been found, including
some around pulsars that we do not discuss here. My physical definition
for a planet is a roughly spherical, self-gravitating body more massive
than 10**26 g formed from the leftover material in a protostellar disk
after the protostar forms. Radiation from the protostar pushes the inner
wall of the disk outward. The material agglomerates and forms planets
in radial sequence. The outer planets are formed slowly by classical
dynamical mechanisms acting in the snow zone. Planets have dense cores
because of agglomeration. Not one of the exoplanets discovered thus
far is a planet. They are cryptoplanets formed from matter ejected by
protostars. When protostars have excessive infall at high latitudes,
they partially balance angular momentum through outflow at the equator
as they spin up. The ejected matter is trapped in the magnetic torus
formed between the star and the disk, like a tokamak. The tokamak
eventully reconnects and magnetic compression forms self-gravitating
remnants trapped and compressed by a closed spherical magnetic field,
spheromaks. Cooled spheromaks are cryptoplanets. They orbit near
the star. They can merge with each other or fall into the star or
be ejected. They can grow by accreting gas. They have a low density
core and abundances characteristic of the protostar. Their masses,
radii, densities, and orbits are random, and are inconsistent with the
parameters for planets. They tend to have lower density than planets.

---------------------------------------------------------
Title: The precession of Mercury and the deflection of starlight by
special relativity alone
Authors: Kurucz, Robert L.
2006astro.ph..8434K Altcode:
I show that the precession of the orbit of Mercury and the deflection
of starlight by the Sun are effects of special relativity alone when
the gravitational field of a particle is treated in the same way as
the electric field of a charged particle . General relativity is not
needed to explain them.

---------------------------------------------------------
Title: Computed Hβ indices from ATLAS9 model atmospheres
Authors: Castelli, F.; Kurucz, R. L.
2006A&A...454..333C Altcode:
Aims.Grids of Hβ indices based on updated (new-ODF) ATLAS9 model
atmospheres were computed for solar and scaled solar metallicities
[+0.5], [+0.2], [0.0], [ -0.5] , [ -1.0] , [ -1.5] , [ -2.0] , [ -2.5]
and for α enhanced compositions [+0.5a], [0.0a], [ -0.5a] , [ -1.0a] ,
[ -1.5a] , [ -2.0a] , [ -2.5a] , and [ -4.0a] . Methods: .Indices
for T_eff &gt; 5000 K were computed with the same methods as described
by Lester et al. (1986, LGK86) except for a different normalization
of the computed natural system to the standard system. LGK86 used
special ODFs to compute the fluxes. For T_eff ≤ 5000 K we computed
the fluxes using the synthetic spectrum method. In order to assess
the accuracy of the computed indices comparisons were made with the
indices computed by Smalley &amp; Dworetsky (1995, A&amp;A, 293, 446,
MD95) and with the empirical relations T_eff-Hβ given by Alonso et
al. (1996, A&amp;A, 313, 873) for several metallicities. Furthermore,
for cool stars, temperatures inferred from the computed indices were
compared with those of the fundamental stars listed by MD95. The same
kind of comparison was made between gravities for B-type stars. Results: .The temperatures from the computed indices are in good
agreement, within the error limits, with the literature values for
4750 K ≤ T_eff ≤ 8000 K, while the gravities agree for T_eff &gt;
9000 K. The computed Hβ indices for the Sun and for Procyon are very
close to the observed values. The comparison between the observed
and computed Hβ indices as function of the observed Hβ has shown a
very small trend which almost completely disappears when only stars
hotter than 10 000 K are considered. The trend due to the cool stars
is probably related with the low accuracy of the fundamental T_eff
which are affected by large errors for most of the stars.

---------------------------------------------------------
Title: Identification of the broad solar emission features near 117 nm
Authors: Avrett, E. H.; Kurucz, R. L.; Loeser, R.
2006A&A...452..651A Altcode: 2006astro.ph..3361A
Wilhelm et al. have recently called attention to the unidentified
broad emission features near 117 nm in the solar spectrum. They
discuss the observed properties of these features in detail but do
not identify the source of this emission. We show that the broad
autoionizing transitions of neutral sulfur are responsible for these
emission features. Autoionizing lines of ion{S}{i} occur throughout
the spectrum between Lyman alpha and the Lyman limit. Sulfur is a
normal contributor to stellar spectra. We use non-LTE chromospheric
model calculations with line data from the Kurucz 2004 ion{S}{i} line
list to simulate the solar spectrum in the range 116 to 118 nm. We
compare the results with SUMER disk-center observations from Curdt
et al. and limb observations from Wilhelm et al. Our calculations
generally agree with the SUMER observations of the broad autoionizing
ion{S}{i} emission features, the narrow ion{S}{i} emission lines,
and the continuum in this wavelength region, and agree with basic
characteristics of the center-to-limb observations. In addition to
modeling the average spectrum, we show that a change of ±200 K in the
temperature distribution causes the intensity to change by a factor
of 4. This exceeds the observed intensity variations 1) with time in
quiet regions at these wavelengths, and 2) with position from cell
centers to bright network. These results do not seem compatible with
current dynamical models that have temporal variations of 1000 K or
more in the low chromosphere.

---------------------------------------------------------
Title: Radiatively-Driven Cosmology in the Cellular Automaton Universe
Authors: Kurucz, Robert L.
2006astro.ph..5469K Altcode:
This is an updated version of my paper "An outline of radiatively-driven
cosmology" (Kurucz 2000). Here the Big Bang universe is replaced by a
finite cellular automaton universe with no expansion (Kurucz 2006). The
Big Bang is replaced by many little bangs spread throughout the universe
that interact to produce the initial perturbations that form Population
III stars, globular clusters, and galaxies, but no large-scale
structure. These perturbations evolve into the universe as we now
observe it. Evolution during the first billion years is controlled
by radiation. Globular clusters are formed by radiatively-driven
implosions, galaxies are formed by radiatively-triggered gravitational
collapse of systems of globular clusters, and voids and the microwave
background are formed by radiatively-driven expansion. After this
period most of the strong radiation sources are exhausted and the
universe relaxes into gravitational old age as we know it. To relieve
the boredom we present the results of gedanken experiments (Kurucz
1992) in a traditional, linear, chronological sequence in the hope of
stimulating research on the many topics considered.

---------------------------------------------------------
Title: Elementary Physics in the Cellular Automaton Universe
Authors: Kurucz, Robert L.
2006astro.ph..5467K Altcode:
General relativity is a mathematical model that uses sophisticated
geometry to describe simple physics. It agrees with experiment
in the few tests that can be made, but the whole edifice is not
physics. Instead of using observations to test that model, I derive a
simple empirical model of elementary physics and cosmology from the
observations. The observations imply that the universe is a finite
cellular automaton; that there is no curved space; that fundamental
particles are massless; that "massy" particles, including electrons,
are composed of fundamental particles; that gravitational mass is
inertial mass; that black holes are made from neutrons compressed into
bosons; that the universe was produced from cold compressed particles,
not radiation; and that the universe is not expanding.

---------------------------------------------------------
Title: High Resolution Irradiance Spectrum from 300 to 1000 nm
Authors: Kurucz, Robert L.
2006astro.ph..5029K Altcode:
The FTS scans that made up the Kitt Peak Solar Flux Atlas by Kurucz,
Furenlid, Brault, and Testerman (1984) have been re-reduced. An
approximate telluric atmospheric model was determined for each FTS
scan. Large-scale features produced by O3 and O2 dimer were computed
and divided out. The solar continuum level was found by fitting a
smooth curve to high points in each scan. The scans were normalized to
the fitted continuum to produce a residual flux spectrum for each FTS
scan. The telluric line spectrum was computed using HITRAN and other
line data for H2O, O2, and CO2. The line parameters were adjusted for
an approximate match to the observed spectra. The scans were divided
by the computed telluric spectra to produce residual irradiance
spectra. Artifacts from wavelength mismatches, deep lines, etc, were
removed by hand and replaced by linear interpolation. Overlapping
scans were fitted together to make a continuous spectrum from 300 to
1000 nm. All the above steps were iterative. The monochromatic error
varies from 0.1 to 1.0 percent. The residual spectrum was calibrated two
different ways: First by normalizing it to the continuum of theoretical
solar model ASUN (Kurucz 1992), and second, by degrading the spectrum
to the resolution of the observed irradiance (Thuillier et al. 2004)
to determine a normalization function that was then applied to the
high resolution spectrum.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Computed Hbeta indices from ATLAS9
model (Castelli+, 2006)
Authors: Castelli, F.; Kurucz, R. L.
2006yCat..34540333C Altcode:
Grids of H{beta} indices based on updated (new-ODF) ATLAS9 model
atmospheres were computed for solar and scaled solar metallicities
[+0.5], [+0.2], [0.0], [-0.5], [-1.0], [-1.5], [-2.0], [-2.5] and
for alpha enhanced compositions [+0.5a], [0.0a], [-0.5a], [-1.0a],
[-1.5a], [-2.0a], [-2.5a], and [-4.0a]. Indices for Teff&gt;5000K were
computed with the same methods as described by Lester, Gray &amp; Kurucz
(1986ApJS...61..509L) (LGK86) except for a different normalization of
the computed natural system to the standard system. LGK86 used special
ODFs to compute the fluxes. For Teff less or equal to 5000K we computed
the fluxes using the synthetic spectrum method. In order to assess
the accuracy of the computed indices comparisons were made with the
indices computed by Smalley &amp; Dworetsky (1995A&amp;A...293..446S)
(MD95) and with the empirical relations Teff-H{beta} given by Alonso et
al. (1996A&amp;A...313..873A) for several metallicities. Furthermore,
for cool stars, temperatures inferred from the computed indices were
compared with those of the fundamental stars listed by MD95. The same
kind of comparison was made between gravities for B-type stars. The
temperatures from the computed indices are in good agreement, within
the error limits, with the literature values for Teff between 4750K
and 8000K, while the gravities agree for Teff&gt;9000K. The computed
H{beta} indices for the Sun and for Procyon are very close to the
observed values. The comparison between the observed and computed
H{beta} indices as function of the observed H{beta} has shown a very
small trend which almost completely disappears when only stars hotter
than 10000K are considered. The trend due to the cool stars is probably
related with the low accuracy of the fundamental Teff which are affected
by large errors for most of the stars. (1 data file).

---------------------------------------------------------
Title: Including all the Lines
Authors: Kurucz, R. L.
2006EAS....18..129K Altcode:
We present a progress report on including all the lines in the
linelists, including all the lines in the opacities, including all
the lines in the model atmosphere and spectrum synthesis calculations,
producing high-resolution, high-signal-to-noise atlases that show (not
quite) all the lines, so that finally we can determine the properties
of stars from a few of the lines.

---------------------------------------------------------
Title: Status of the physics of substellar objects
Authors: Jones, H. R. A.; Viti, S.; Tennyson, J.; Barber, B.; Harris,
G.; Pickering, J. C.; Blackwell-Whitehead, R.; Champion, J. -P.;
Allard, F.; Hauschildt, P. H.; Jorgensen, U. G.; Ehrenfreund, P.;
Stachowska, E.; Ludwig, H. -G.; Martin, E.; Pavlenko, Ya.; Lyubchik,
Yu.; Kurucz, R. L.
2005AN....326..920J Altcode:
A full understanding of the properties of substellar objects is one
of the major challenges facing astrophysics. Since their discovery
in 1995, we have discovered hundreds of brown dwarfs and extrasolar
planets. While these discoveries have enabled important comparisons
with theory, observational progress has been much more rapid than
the theoretical understanding of cool atmospheres. The reliable
determination of mass, abundances, gravities and temperatures is not
yet possible. The key problem is that substellar objects emit their
observable radiation in the infrared region of the spectrum where our
knowledge of atomic, molecular and line broadening data is poor. Here
we report on the status of PoSSO (Physics of SubStellar Objects). In
order to understand brown dwarfs and extrasolar planets increasing
more like those in our solar system, we are studying a wide range of
processes. Here we give an update on the project and sketch an outline
of atoms, molecules and processes requiring study.

---------------------------------------------------------
Title: ACCESS - Absolute Color Calibration Experiment for Standard
Stars
Authors: Kaiser, M. E.; Dixon, W. V.; Feldman, P. D.; Kruk, J. W.;
McCandliss, S. R.; Moos, H. W.; Sahnow, D. J.; Rauscher, B. J.;
Gardner, J. P.; Kimble, R. A.; Schwartz, P. C.; Woodgate, B. E.;
Bohlin, R. C.; Deustua, S. E.; Kurucz, R.; Perlmutter, S.
2005AAS...20717312K Altcode: 2005BAAS...37.1440K
ACCESS is a proposed series of rocket-borne sub-orbital missions whose
purpose is to establish a network of standard stars with absolute
fluxes that are directly traceable to ground based laboratory standards
maintained by NIST. Our goal is to obtain an absolute spectrophotometric
calibration accuracy of &lt;1% in the 0.35-1.7 micron bandpass at a
spectral resolution of greater than 500. This represents a significant
improvement in the absolute calibration in the NIR bandpass. This
fundamental astrophysics experiment will establish the first links
in a chain of stellar calibrators including standard stars (10th
magnitude) observable by major telescopes, thus enabling the ultimate
calibration to extend to faint magnitudes. This calibration
program is important for a broad range of missions and relevant to
many astrophysical problems. In particular, it is fundamental to
photometrically based dark energy missions which use supernova type Ia.

---------------------------------------------------------
Title: How Similar are Starspots to Sunspots?
Authors: Rajaguru, S. P.; Kurucz, R. L.; Hasan, S. S.
2005BASI...33..362R Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Solar Oxygen Abundance, and the Rare Isotopes of C and O,
Derived from Infrared Spectra of Carbon Monoxide
Authors: Ayres, T. R.; Plymate, C.; Keller, C.; Kurucz, R. L.
2005AGUSMSP41B..09A Altcode:
A detailed abundance analysis is presented for solar oxygen based on
the ΔV=1 fundamental (4.6~μm) and ΔV=2 (2.3~μm) first-overtone
rovibrational bands of carbon monoxide observed above the Earth's
atmosphere at very high spectral resolution and high signal-to-noise by
the Shuttle-borne ATMOS Fourier transform spectrometer (FTS). Additional
observations to define the reference photospheric thermal structure
were taken of the CO fundamental bands in an atmospheric window at
2145~cm-1 (4.6~μm) using the 1~m FTS of the McMath-Pierce telescope
at Kitt Peak and a fast tip/tilt image stabilization system. The latter
allowed measurements at the extreme limb where the highly slanted rays
probe into the outer layers of the photosphere. High spatial resolution
"movies" of weak CO lines at disk center taken under excellent seeing
conditions with the Infrared Imaging Spectrometer (IRIS), also on
the McMath-Pierce telescope, further constrained thermal and velocity
fluctuations in the layers in which the abundance-sensitive CO lines
form. This work is meant to complement a series of recent studies
which have revised the previously recommended solar oxygen abundance
downward by nearly a factor of two; although in fact our conclusions
do not support such a revision. The oxygen abundance recovered in the
present work is 700±70~ppm (parts per million relative to hydrogen)
compared with the proposed downward revision to 460±60~ppm, and the
recommended value of 650±100~ppm of a decade ago. In our analysis,
a fixed C/O ratio of 0.5, derived in independent work, was assumed;
so the associated carbon abundance is 350~ppm. New accurate values
for the solar abundance ratios of the rare isotopes of C and O also
are reported: 12C/13C= 70, 16O/17O= 400, and 16O/18O= 2000. All three
ratios are lower than terrestrial or meteoritic values (indicating
higher isotopic abundances). We find no evidence in the ATMOS3 spectra
for measurable 14C16O lines.

---------------------------------------------------------
Title: New atlases for solar flux, irradiance, central intensity,
and limb intensity
Authors: Kurucz, Robert L.
2005MSAIS...8..189K Altcode:
I have produced a revised FTS Kitt Peak Solar Flux Atlas for 300 to
1000 nm (Kurucz 2005) and a new high resolution Kitt Peak Irradiance
Atlas from 300 to 1000 nm with the telluric lines removed. I am now
working on central intensity and limb intensity atlases for the same
region. If I can get funding I will extend these atlases to 5.5 mu
m. I will also produce atlases with the observed and computed spectra
and line identifications.

---------------------------------------------------------
Title: Physical, numerical, and computational limits for Kurucz codes
Authors: Kurucz, Robert L.
2005MSAIS...8...73K Altcode:
We outline physical, numerical, and computational limits on Kurucz's
codes, for model atmospheres, ATLAS12 and ATLAS9, spectrum synthesis,
SYNTHE, and abundance analysis, WIDTH9.

---------------------------------------------------------
Title: ATLAS12, SYNTHE, ATLAS9, WIDTH9, et cetera
Authors: Kurucz, Robert L.
2005MSAIS...8...14K Altcode:
The problem we address is including the opacity of millions or hundreds
of millions of lines in model stellar atmosphere calculations, then
generating detailed, realistic spectra from those model atmospheres,
then modelling the observation process, and finally comparing the
calculated spectra to observed spectra to determine the properties
of stars so that we can understand their evolution and the evolution
of galaxies. We describe the current status of Kurucz's programs and
atomic and molecular line data.

---------------------------------------------------------
Title: Rapid computation of line opacity in SYNTHE and DFSYNTHE
Authors: Kurucz, Robert L.
2005MSAIS...8...76K Altcode:
Methods are suggested for speeding up the computation of opacity.

---------------------------------------------------------
Title: PoSSO Physics of SubStellar Objects
Authors: Jones, Hugh; Viti, Serena; Tennyson, Jonathan; Barber, Bob;
Pickering, Juliet; Blackwell-Whitehead, Richard; Champion, Jean-Paul;
Allard, France; Hauschildt, Peter; Jørgensen, Uffe; Ehrenfreund,
Pascale; Stachowska, Ewa; Ludwig, Hans-Günter; Pavlenko, Yakiv;
Lyubchik, Yuri; Kurucz, Robert
2005hris.conf..477J Altcode:
A full understanding of the properties of substellar objects is one
of the major challenges facing astrophysics. Since their discovery
in 1995, we have discovered hundreds of brown dwarfs and extrasolar
planets. While these discoveries have enabled important comparisons
with theory, observational progress has been much more rapid than the
theoretical understanding of cool atmospheres. The determination of
mass, abundances, gravities and temperatures is not yet possible. The
key problem is that substellar objects emit their observable radiation
in the infrared region of the spectrum where our knowledge of atomic,
molecular and line broadening data is poor. In order to understand
these objects, and extra-solar planets increasing more like those our
Solar System, we urge the wider physical chemistry community to engage
in this exciting new field. Here we sketch an outline of the atoms,
molecules and processes requiring study.

---------------------------------------------------------
Title: Including all the lines
Authors: Kurucz, Robert L.
2005MSAIS...8...86K Altcode:
Of the line data on my website, 99 % have predicted wavelengths and can
be used only to compute opacities. One percent have good wavelengths
between known levels and can be used for detailed spectrum calculations
for comparision to observed spectra. The line data with good wavelengths
account for only one-half of the observed lines. The gf values and
damping constants for most lines must be adjusted to match observed
spectra. We know that the higher configurations are missing from the
line lists. We know that heavier elements are missing from the line
lists. We know that isotopic and hyperfine splittings are missing from
the line lists. We know that many molecules are missing from the line
lists. Leaving out all these lines systematically underestimates the
opacity, produces energy distributions with systematic errors, and
leads to abundance determinations with large systematic errors. We
need much better laboratory analyses including hyperfine and isotopic
splitting. We need better calculations that fill in the higher
configurations and the heavier elements. We need better measurements and
calculations for all the significant diatomic and polyatomic molecules
including all the isotopomers. I am doing as much as I can to fill in
the missing data and to make it available on my web site.

---------------------------------------------------------
Title: The binary progenitor of Tycho Brahe's 1572 supernova
Authors: Ruiz-Lapuente, Pilar; Comeron, Fernando; Méndez, Javier;
Canal, Ramon; Smartt, Stephen J.; Filippenko, Alexei V.; Kurucz, Robert
L.; Chornock, Ryan; Foley, Ryan J.; Stanishev, Vallery; Ibata, Rodrigo
2004Natur.431.1069R Altcode: 2004astro.ph.10673R
The brightness of type Ia supernovae, and their homogeneity as a class,
makes them powerful tools in cosmology, yet little is known about the
progenitor systems of these explosions. They are thought to arise when
a white dwarf accretes matter from a companion star, is compressed
and undergoes a thermonuclear explosion. Unless the companion star
is another white dwarf (in which case it should be destroyed by the
mass-transfer process itself), it should survive and show distinguishing
properties. Tycho's supernova is one of only two type Ia supernovae
observed in our Galaxy, and so provides an opportunity to address
observationally the identification of the surviving companion. Here
we report a survey of the central region of its remnant, around the
position of the explosion, which excludes red giants as the mass donor
of the exploding white dwarf. We found a type G0-G2 star, similar to our
Sun in surface temperature and luminosity (but lower surface gravity),
moving at more than three times the mean velocity of the stars at that
distance, which appears to be the surviving companion of the supernova.

---------------------------------------------------------
Title: A Calibration of FWHM vs. υ for UV Lines
Authors: Ramírez, I.; Koenigsberger, G.; Kurucz, R. L.
2004IAUS..215...19R Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Is missing Fe I opacity in stellar atmospheres a significant
problem?
Authors: Castelli, F.; Kurucz, R. L.
2004A&A...419..725C Altcode:
We present an empirical model-atmosphere investigation of missing Fe
I opacity. Houdashelt et al. (\cite{houd00}) estimated that if Dragon
&amp; Mutschlecner (\cite{dm80}) Fe I cross sections used in the MARCS
model atmospheres (Gustafsson et al. \cite{gus75}) were replaced by
the Bautista (\cite{bau97}) cross sections the solar continuous flux
would be reduced by 15% in the near ultraviolet. That would imply
systematic errors in models for F, G, and K stars. As a consequence,
since ATLAS9 (Kurucz \cite{k93a}) uses an approximation to the same
Dragon &amp; Mutschlecner (\cite{dm80}) opacities, there should also
be similar systematic errors in ATLAS9 models that required this
investigation. Bound-free Fe I cross sections computed by Bautista
(\cite{bau97}) in the framework of the IRON Project were used to
generate the continuous Fe I absorption coefficient. It was incorporated
in the Kurucz (\cite{k93a}) ATLAS9 code, in place of that currently
used, which is based on approximate cross sections by Kurucz. By
combining Opacity Distribution Functions (ODFs) computed without the
contribution of Fe I autoionization lines with the new Fe I absorption
coefficient which is crowded with autoionization resonances, we obtained
solar metallicity model atmospheres and energy distributions for several
combinations of T_eff and log g. The comparison of these models with
the standard ATLAS9 models has shown that there are no differences in
the T-τRoss relations, while there are some changes in the
energy distributions for Teff,≤ 7000 K, but limited to
small wavelength regions around 2150 Å, where Kurucz has less opacity,
and 3350 Å, where Bautista has less opacity. The differences are of
the order of 25% and less than 10%, respectively. That around 2150 Å
disappears for Teff,≤ 5500 K owing to the fall of the
emergent flux at these wavelengths in cool stars. This behaviour is
independent of the gravity. The explanation is that our line list
actually has more autoionizing opacity than Bautista's but it is
treated as bound-bound line opacity rather than as bound-free opacity.

---------------------------------------------------------
Title: ATLAS and SYNTHE under Linux
Authors: Sbordone, L.; Bonifacio, P.; Castelli, F.; Kurucz, R. L.
2004MSAIS...5...93S Altcode: 2004astro.ph..6268S
We have successfully ported under GNU Linux ATLAS 9, the widely used
stellar atmosphere modeling code, as well as both the SYNTHE suite of
programs, its “companion” for spectral synthesis, and WIDTH, used to
derive chemical abundances from equivalent widths of spectral lines. The
porting has been realized by using the Intel Fortran Compiler. Our aim
was to port the codes with the minimum possible amount of modifications:
full compatibility with the VMS version has been maintained, along with
all the codes functionalities. Dramatic improvement in calculation
speed with respect to the VMS version has been achieved. The full
suite of codes is intended to be freely available to everyone.

---------------------------------------------------------
Title: Spatially Resolved STIS Spectroscopy of Betelgeuse's Outer
Atmosphere
Authors: Lobel, A.; Aufdenberg, J.; Dupree, A. K.; Kurucz, R. L.;
Stefanik, R. P.; Torres, G.
2004IAUS..219..641L Altcode: 2003IAUS..219E.158L; 2003astro.ph.12076L
We present spatially resolved spectra observed with HST-STIS of the
upper chromosphere and dust envelope of Alpha Orionis (M2 Iab). In the
fall of 2002 a set of five high-resolution near-UV spectra was obtained
by scanning at intensity peak-up position and four off-limb target
positions up to one arcsecond, using a small aperture, to investigate
the thermal conditions and flow dynamics in the outer atmosphere of
this important nearby cool supergiant star. Based on Mg II h &amp; k,
Fe II 2716 A, C II 2327 A, and Al II ] 2669 A emission lines we provide
the first evidence for the presence of warm chromospheric plasma at
least 1 arcsecond away from the star at ~40 R* (1 R*~700 Rsun). The
STIS spectra reveal that Betelgeuse's upper chromosphere extends far
beyond the circumstellar H alpha envelope of ~5 R*, determined from
previous ground-based imaging. The flux in the broad and self-absorbed
resonance lines of Mg II decreases by a factor of ~700 compared to
the flux at chromospheric disk center. We observe strong asymmetry
changes in the Mg II h and Si I resonance line profiles when scanning
off-limb, signaling the outward acceleration of gas outflow in the
upper chromosphere. From the radial intensity distributions of Fe I and
Fe II emission lines we determine the radial non-LTE iron ionization
balance. We compute that the local kinetic gas temperatures of the
warm chromospheric gas component in the outer atmosphere exceed 2600
K, when assuming local gas densities of the cool gas component we
determine from radiative transfer models that fit the 9.7 um silicate
dust emission feature. The spatially resolved STIS spectra directly
demonstrate that warm chromospheric plasma co-exisists with cool gas
in Betelgeuse's circumstellar dust envelope.

---------------------------------------------------------
Title: New Grids of ATLAS9 Model Atmospheres
Authors: Castelli, F.; Kurucz, R. L.
2003IAUS..210P.A20C Altcode: 2004astro.ph..5087C
New opacity distribution functions (ODFs) for several metallicities
have been computed. The main improvements upon previous ODFs computed
by Kurucz (1990) are: (1) the replacement of the solar abundances from
Anders &amp; Grevesse (1989) with those from Grevesse &amp; Sauval
(1998); (2) the replacement of the TiO lines provided by Kurucz
(1993) with the TiO lines from Schwenke (1998), as distributed by
Kurucz (1999a); (3) the addition of the H2O lines from
Partridge &amp; Schwenke (1997), as distributed by Kurucz (1999b);
(4) the addition of the H I-H I and H I-H+ quasi-molecular
absorptions near 1600Å and 1400Å computed according to Allard et
al. (1998). Other minor improvements are related with some changes in
a few atomic and molecular data. New grids of ATLAS9 model atmospheres
for Teff from 3500 K to 50000 K and log g from 0.0 dex
to 5.0 dex have been computed for several metallicities with the new
ODFs. Preliminary comparisons of results from the old and new models
have shown differences in the energy distributions of stars cooler
than 4500 K, in the ultraviolet energy distribution of metal-poor
A-type stars, in the U-B and u-b color indices for Teff
≤ 6750 K and in all the color indices for Teff ≤ 4000 K.

---------------------------------------------------------
Title: Search for the Companions of Galactic SNe Ia
Authors: Ruiz-Lapuente, Pilar; Comeron, Fernando; Smartt, Stephen;
Kurucz, Robert; Mendez, Javier; Canal, Ramon; Filippenko, Alex;
Chornock, Ryan
2003fthp.conf..140R Altcode: 2003astro.ph..4109R
The central regions of the remnants of Galactic SNe Ia have
been examined for the presence of companion stars of the exploded
supernovae. We present the results of this survey for the historical
SN 1572 and SN 1006. The spectra of the stars are modeled to obtain
Teff, log g and the metallicity. Radial velocities are obtained with
an accuracy of 5-10 km s-1. Implications for the nature of
the companion star in SNeIa follow.

---------------------------------------------------------
Title: A Few Things We Do Not Know About Stars and Model Atmospheres
Authors: Kurucz, R. L.
2003IAUS..210...45K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Photospheric Absorption Lines in the Ultraviolet Spectrum
of the Multiple System HD 5980
Authors: Koenigsberger, Gloria; Kurucz, Robert L.; Georgiev, Leonid
2002ApJ...581..598K Altcode:
We search for radial velocity variations in the ultraviolet spectra of
the erupting Wolf-Rayet/luminous blue variable system HD 5980, located
in the Small Magellanic Cloud. We obtain an average radial velocity of
22+/-22 km s-1 for five observations in 1999 at different
orbital phases, -39+/-24 km s-1 for one observation in
2001, and 20+/-45 km s-1 for one observation in 2002. These
velocities are with respect to the SMC O3 star MPG 355, which is used as
one of the templates. Hence, radial velocity variations on the 19.265
day (star A+star B) orbital timescale attributable to the erupting
star (star A) of the system are not detected, thus confirming that the
visible absorption lines in the spectrum have their origin in a third
stellar component (star C). We propose that star A has very broad
(vsini~250 km s-1) absorption lines, which would escape
detection in the complicated emission-line spectrum of the system. Such
broad lines, combined with the 128 km s-1 orbital motion,
would lead to a lower amplitude fictitious radial velocity curve
when the stationary set of absorption lines is measured. We conclude
that line profile variations at orbital phase 0.0 from one epoch of
observations to another are associated with these broad underlying
absorption lines, arising in the unstable photosphere of star A. The
analysis is performed with the aid of synthetic UV spectra that are
calculated from LTE line-blanketed atmosphere models, and the HST Space
Telescope Imaging Spectrograph spectra of four O-type stars in the
cluster NGC 346, to which HD 5980 is believed to belong. We estimate
Teff and obtain values of vsini and the mean radial velocity
for MPG 324 [O4 V((f))], MPG 368 [O4-5 V((f))], MPG 355 [O3 V(f*)],
and MPG 113 (OC 6Vz). Based on observations with the NASA/ESA Hubble
Space Telescope obtained at the Space Telescope Science Institute,
which is operated by the Association of Universities for Research in
Astronomy, Inc., under NASA contract NAS 5-26555.

---------------------------------------------------------
Title: The Progenitor of Supernova 1993J Revisited
Authors: Van Dyk, Schuyler D.; Garnavich, Peter M.; Filippenko,
Alexei V.; Höflich, Peter; Kirshner, Robert P.; Kurucz, Robert L.;
Challis, Peter
2002PASP..114.1322V Altcode: 2002astro.ph..8382V
From Hubble Space Telescope images with 0.05" resolution, we identify
four stars brighter than V=25 mag within 2.5" of SN 1993J in M81,
which contaminated previous ground-based brightness estimates for the
supernova progenitor. Correcting for the contamination, we find that
the energy distribution of the progenitor is consistent with that of
an early K-type supergiant star with MV~-7.0+/-0.4 mag and
an initial mass of 13-22 Msolar. The brightnesses of the
nearby stars are sufficient to account for the excess blue light seen
from the ground in preexplosion observations. Therefore, the SN 1993J
progenitor did not necessarily have a blue companion, although by 2001,
fainter blue stars are seen in close proximity to the supernova. These
observations do not strongly limit the mass of a hypothetical
companion. A blue dwarf star with a mass up to 30 Msolar
could have been orbiting the progenitor without being detected in the
ground-based images. Explosion models and observations show that SN
1993J progenitor had a helium-rich envelope. To test whether the helium
abundance could influence the energy distribution of the progenitor,
we calculated model supergiant atmospheres with a range of plausible
helium abundances. The models show that the presupernova colors are
not strongly affected by the helium abundance longward of 4000 Å,
and abundances ranging between solar and 90% helium (by number) are
all consistent with the observations. Based on observations made with
the NASA/ESA Hubble Space Telescope, obtained in part from the data
archive of the Space Telescope Science Institute, which is operated
by the Association of Universities for Research in Astronomy, Inc.,
under NASA contract NAS 5-26555.

---------------------------------------------------------
Title: Atomic and molecular data needs for astrophysics
Authors: Kurucz, Robert L.
2002AIPC..636..134K Altcode:
We need a list of all the energy levels of all atoms and molecules
that matter (qualifiers below). Except for the simplest species,
it is impossible to generate accurate energy levels or wavelengths
theoretically. They must be measured in the laboratory. From the
list of energy levels can be generated all the lines. Given the low
accuracy required, 1 - 10%, all the other data we need can eventually be
computed or measured. With the energy levels and line positions known,
one can measure gf values, lifetimes, damping, or one can determine
a theoretical or semiempirical Hamiltonian whose eigenvalues and
eigenvectors produce a good match to the observed data, and that
can then be used to generate additional radiative and collisional
data for atoms or molecules. For atoms and ions, we need all levels,
including hyperfine and isotopic splittings, for n &lt;= 9 below the
lowest ionization limit and as much as practicable above. Lifetimes
and damping constants depend on sums over the levels. Inside stars
there are thermal and density cutoffs that limit the number of
levels, but in circumstellar, interstellar, and intergalactic space,
photoionization and recombination can populate high levels, even for
high ions. We need all stages of ionization for elements at least up
through Zn. In the sun there are unidentified asymmetric triangular
features that are unresolved multiplets of light elements with n
.le. 20. Simple spectra should be analyzed up to n = 20. Levels that
connect to the ground or to low levels should be measured to high
n, say n = 80. The high levels are necessary to match line series
merging into continua. All the magnetic dipole, electric quadrupole,
and maybe higher-pole, forbidden lines are required as well. Most
of the universe is low density plasma or gas. If the Hamiltonian is
well determined, forbidden lines should be reliably computable. For
molecules, we need all levels below the first dissociation limit and
as much as is practicable above, especially levels of all states that
connect to the ground state. Stars populate levels to high V and to high
J. In the sun there are many broad bumpy features that are molecular
bands that are not in the line lists. For the cooler stars we need
all the diatomics among all the abundant elements, and, essentially,
the hydrides and oxides for all elements (especially ScO, TiO, VO,
YO, ZrO, LaO). For M stars triatomics also become important. Much
more laboratory and computational work is needed for H2O. In the brown
dwarfs and "planets" methane is important and it needs more laboratory
and computational work. We can produce more science by investing in
laboratory spectroscopy rather than by building giant telescopes that
collect masses of data that cannot be correctly interpreted.

---------------------------------------------------------
Title: Convective Intensification of Magnetic Flux Tubes in Stellar
Photospheres
Authors: Rajaguru, S. P.; Kurucz, R. L.; Hasan, S. S.
2002ApJ...565L.101R Altcode: 2002astro.ph..1026R
The convective collapse of thin magnetic flux tubes in the
photospheres of Sun-like stars is investigated using realistic
models of the superadiabatic upper convection zone layers of these
stars. The strengths of convectively stable flux tubes are computed as
a function of surface gravity and effective temperature. We find that
while stars with Teff&gt;=5500 K and logg&gt;=4.0 show flux
tubes highly evacuated of gas, and hence strong field strengths due to
convective collapse, cooler stars exhibit flux tubes with lower field
strengths. Observations reveal the existence of field strengths close
to thermal equipartition limits even in cooler stars, implying highly
evacuated tubes, for which we suggest possible reasons.

---------------------------------------------------------
Title: A Few Things We Do Not Know About the Sun and F-G Stars
Authors: Kurucz, R. L.
2002BaltA..11..101K Altcode: 2002OAst...11..101K
We do not: know how to make realistic model atmospheres, understand
convection, consider variation in microturbulent velocity, understand
spectroscopy, have good spectra of the Sun or any star, have energy
distributions for the Sun or any star, know how to determine abundances,
know the abundances of the Sun or any star, have good atomic and
molecular data, identify one half of the lines in solar spectrum.

---------------------------------------------------------
Title: A few things we do not know about stars and model atmospheres
Authors: Kurucz, Robert L.
2002ASSL..274....3K Altcode: 2001astro.ph..5400K
We list a few things that we do not understand about stars and that most
people ignore. These are all hard problems. We can learn more cosmology
by working on them to reduce the systematic errors they introduce than
by trying to derive cosmological results that are highly uncertain.

---------------------------------------------------------
Title: Research on Spectroscopy, Opacity, and Atmospheres
Authors: Kurucz, Robert L.
2001STIN...0212434K Altcode:
With this funding I produced a web site kurucz.harvard.edu that can also
be accessed by FTP. it has a 73GB disk that holds all of my atomic and
diatomic molecular data, my tables of distribution function opacities,
my grids of model atmospheres, colors, fluxes, etc., my programs that
are ready for distribution, and most of my recent papers. Atlases and
computed spectra will be added as they are completed. New atomic and
molecular calculations will be added as they are completed.

---------------------------------------------------------
Title: Ultraviolet spectra for lambda Boo (HD 125162) computed with
H2 opacities and Lyman-alpha H-H and H-H+
opacities
Authors: Castelli, F.; Kurucz, R. L.
2001A&A...372..260C Altcode:
New opacity distribution functions (ODF) have been computed for
use with the ATLAS9 model atmosphere code of Kurucz. One of the
improvements upon the Kurucz (\cite{kur90}) ODFs is the addition
to the line blanketing of the Lyman-alpha H-H and H-H+
quasi-molecular absorptions near 1600 Å and 1400 Å. New-ODF fluxes
are expected to reproduce the ultraviolet observations of lambda Boo
stars and metal-poor A-type stars in a more realistic way than previous
computations did. In this paper we compare low- and high-resolution
IUE observations of lambda Boo (HD 125162, HR 5351) with fluxes and
synthetic spectra based on ATLAS9 models and new-ODFs, which were
computed for [M/H]=-2.0 for all the elements, except CNO. For C, N, and
O, abundances log (Nelem/Ntot) equal to -3.85,
-3.99, and -3.11, respectively, were adopted. We selected lambda Boo
in order to compare results from the new-ODFs with those from Allard et
al. (\cite{allar98a}, \cite{allar98b}), who tested their semi-classical
computations of the H-H and H-H+ quasi-molecular absorptions
on this star. The analysis of the IUE high-resolution spectrum has
shown that lines of H2 are a very important source of line
opacity for lambda Boo shortward 1600 Å. When both atomic and molecular
lines are considered, the slope of the observed energy distribution is
well reproduced in the whole region 1300-3000 Å by the new-ODF model,
but the H-H quasi-molecular absorption at 1600 Å is computed about
10% too strong. The fit of the low-resolution IUE image SWP17872 to a
small grid of new-ODF models gives parameters Teff= 8650
K, log g=4.0, while the fit of the high-resolution image SWP42081,
rebinned at the low resolution wavelength step size, gives parameters
Teff=8500 K, log g=4.0. These last parameters are in close
agreement with Teff=8550 K, log g=4.1 obtained by fitting
the visible energy distribution. The different IUE images are discussed.

---------------------------------------------------------
Title: The "Extra-Solar Giant Planets" are Brown Dwarfs
Authors: Kurucz, Robert L.
2001astro.ph..5160K Altcode:
After an M, K, G, or F star forms, it magnetically compresses the
infall dregs to produce a close in brown dwarf.

---------------------------------------------------------
Title: The formation of life
Authors: Kurucz, Robert L.
2000astro.ph.11209K Altcode:
The formation of life is an automatic stage in the consolidation of
rocky or "terrestrial" planets. The organic (=carbonaceous) matter,
light elements, gases, and water must "float" toward the surface and
the heavier metals must sink toward the center. Random processes
in the molecular soup that fills microfractures in unmelted crust
eventually produce self-replicating microtubules. In an appendix
I suggest that some primordial crust remains because there is not
enough consolidation energy to melt the whole planet. Energy is lost
when iron planetesimals first partially melt and then coalesce to form
the molten iron planetary core. Stony planetesimals accrete onto the
surface of an already consolidated core.

---------------------------------------------------------
Title: Solar Spectroscopy: Visible Emission
Authors: Kurucz, R.
2000eaa..bookE2232K Altcode: 2001EAA.....3.2744K
There are several perspectives from which to consider the solar
spectrum. One is obviously as a tool for studying the Sun itself. The
temperature and pressure variation with depth, the composition, the
magnetic fields, the changing structure and velocity fields on the
surface can be derived from high-resolution, high signal-to-noise
spectra that also have high spatial and temporal resolution....

---------------------------------------------------------
Title: A correction to the pp reaction
Authors: Kurucz, Robert L.
2000astro.ph..3029K Altcode:
These descriptive comments are made to encourage detailed three-body,
relativistic, quantum collision calculations for the pp reaction. In
stars, coulomb barrier tunneling, as in the pp reaction, is not a
two-body process. Tunneling is mediated by an energetic electron that
interacts with the colliding particles. The presence of such an electron
lowers the potential barrier and increases the probability of tunneling
by orders of magnitude. The solar luminosity can be maintained with
a central temperature near 10 million K where the neutrino production
rates correspond to the observed rates. Current stellar interior and
evolutionary models need substantial revision.

---------------------------------------------------------
Title: A few things we do not know about the sun and F stars and
G stars
Authors: Kurucz, Robert L.
2000astro.ph..3069K Altcode:
WE do not know how to make realistic model atmospheres; understand
convection; consider the variation in microturbulent velocity;
understand spectroscopy; have good spectra of the sun or any other
star; have energy distributions for the sun or any other star; know
how to determine abundances; know the abundances of the sun or any
other star; have good atomic and molecular data; One half the lines
in the solar spectrum are not identified. We should get our own house
in order before worrying about the neighbors.

---------------------------------------------------------
Title: An outline of radiatively-driven cosmology
Authors: Kurucz, Robert L.
2000astro.ph..3381K Altcode:
A Big Bang universe consisting, before recombination, of H, D, 3He,
4He, 6Li, and 7Li ions, electrons, photons, and massless neutrinos,
at closure density, with a galaxy-size perturbation spectrum but
no large-scale structure, will evolve into the universe as we now
observe it. Evolution during the first billion years is controlled
by radiation. Globular clusters are formed by radiatively-driven
implosions, galaxies are formed by radiatively triggered gravitational
collapse of systems of globular clusters, and voids are formed by
radiatively-driven expansion. After this period the strong radiation
sources are exhausted and the universe has expanded to the point where
further evolution is determined by gravity and universal expansion.

---------------------------------------------------------
Title: Working Group on Infrared Astronomy: (Groupe de Travail Pour
L'Astronomie Infrarouge)
Authors: Milone, Eugene F.; Bell, Roger A.; Bessell, Michael;
Garrison, Robert; Cohen, Martin; Glass, Ian S.; Kurucz, Robert L.;
Mountain, Matthew; Riecke, George; Schiller, Stephen J.; Simon,
Douglas; Skrutskie, Michael; Stagg, Christopher S.; Sterken, Chris;
Thompson, Roger I.; Tokunaga, Alan; Young, Andrew T.
2000IAUTA..24..336M Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Acoustic wave energy fluxes for late-type stars. II. Nonsolar
metallicities
Authors: Ulmschneider, P.; Theurer, J.; Musielak, Z. E.; Kurucz, R.
1999A&A...347..243U Altcode:
Using the Lighthill-Stein theory with modifications described by
Musielak et al. (1994), the acoustic wave energy fluxes were computed
for late-type stars with the solar metal abundance (population I stars)
by Ulmschneider et al. (1996). We now extend these computations to
stars with considerably lower metal content (population II stars
with 1/10 to 1/1000 of solar metallicity) and find that the acoustic
fluxes calculated for stars of different spectral types and different
luminosities are affected differently by the metallicity. It is found
that the Hertzsprung-Russel diagram can be subdivided into three domains
(labeled I, II and III) representing a different dependence of the
generated acoustic fluxes on the stellar metal abundance. For the
high T_eff stars of domain I there is no dependence of the generated
acoustic fluxes on metallicity. In domain III are stars with low
T_eff. Here the generated acoustic fluxes are lowered roughly by an
order of magnitude for every decrease of the metal content by an order
of magnitude. Finally, domain II represents the transition between the
other two domains and the generated acoustic fluxes strongly depend
on T_eff. The boundaries between the domains I and II, and II and
III can be defined by simple relationships between stellar effective
temperatures and gravities.

---------------------------------------------------------
Title: Calculation of Solar Irradiances. I. Synthesis of the Solar
Spectrum
Authors: Fontenla, Juan; White, Oran R.; Fox, Peter A.; Avrett,
Eugene H.; Kurucz, Robert L.
1999ApJ...518..480F Altcode:
Variations in the total radiative output of the Sun as well as
the detailed spectral irradiance are of interest to terrestrial
and solar-stellar atmosphere studies. Recent observations provide
measurements of spectral irradiance variations at wavelengths in the
range 1100-8650 Å with improved accuracy, and correlative studies
give procedures for estimating the spectral irradiance changes from
solar activity records using indicators such as those derived from
Ca II K and Mg II indices. Here we describe our approach to physical
modeling of irradiance variations using seven semiempirical models to
represent sunspots, plage, network, and quiet atmosphere. This paper
gives methods and details, and some preliminary results of our synthesis
of the variations of the entire irradiance spectrum. Our calculation
uses object-oriented programming techniques that are very efficient
and flexible. We compute at high spectral resolution the intensity
as a function of wavelength and position on the disk for each of the
structure types corresponding to our models. These calculations include
three different approximations for the line source function: one suited
for the very strong resonance lines where partial redistribution
(PRD) is important, another for the most important nonresonance
lines, and another approximation for the many narrow lines that are
provided in Kurucz's listings. The image analysis and calculations
of the irradiance variation as a function of time will be described
in a later paper. This work provides an understanding of the sources
of variability arising from solar-activity surface structures. We
compute the Lyα irradiance to within 3% of the observed values. The
difference between our computations and the Neckel &amp; Labs data is 3%
or less in the near-IR wavelengths at 8650 Å, and less than 1% in the
red at 6080 Å. Near 4100 Å we overestimate the irradiance by 9%-19%
because of opacity sources missing in our calculations. We also compute
a solar cycle variability of 49% in the Lyα irradiance, which is very
close to observed values. At wavelengths between 4100 Å and 1.6 μm,
we obtain spectral irradiance variations ranging from -0.06% to 0.46%
in the visible--the higher values correspond to the presence of strong
lines. The variability in the IR between 1.3 and 2.2 μm is ~-0.15%.

---------------------------------------------------------
Title: Effect of the variation of electronic dipole moment on
theoretical spectra: application to the λ Bootis stars
Authors: Allard, N. F.; Drira, I.; Faraggiana, R.; Gerbaldi, M.;
Kielkopf, J. F.; Kurucz, R.
1999AIPC..467..264A Altcode: 1999sls..conf..264A
No abstract at ADS

---------------------------------------------------------
Title: 1999 TiO linelist from Schwenke (1998).
Authors: Kurucz, Robert
1999KurCD..24.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: H2O linelist from Partridge and Schwenke (1997), part 1 of 2.
Authors: Kurucz, Robert
1999KurCD..25.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: New Lyman alpha-opacities and consequences on stellar spectra
Authors: Allard, N. F.; Drira, I.; Faraggiana, R.; Gerbaldi, M.;
Kielkopf, J. F.; Kurucz, R.
1999ASPC..169..457A Altcode: 1999ewwd.conf..457A
No abstract at ADS

---------------------------------------------------------
Title: H2O linelist from Partridge and Schwenke (1997), part 2 of 2.
Authors: Kurucz, Robert
1999KurCD..26.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Fe II emission lines in the UV spectrum of Sirius-A and VEGA
Authors: van Noort, M.; Lanz, T.; Lamers, H. J. G. L. M.; Kurucz,
R. L.; Ferlet, R.; Hebrard, G.; Vidal-Madjar, A.
1998A&A...334..633V Altcode: 1998astro.ph..3127V
We present high-quality HST/GHRS spectra in the Hydrogen Lalpha
spectral region of Vega and Sirius-A. Thanks to the signal-to-noise
ratio achieved in these observations and to the similarity of the two
spectra, we found clear evidence of emission features in the low flux
region, lambda lambda 1190-1222 Angstroms. These emission lines can
be attributed unambiguously to Fe Ii and Cr Ii transitions. In this
spectral range, silicon lines are observed in absorption. We built
a series of non-LTE model atmospheres with different, prescribed
temperature stratification in the upper atmosphere and treating Fe
Ii with various degrees of sophistication in non-LTE. Emission lines
are produced by the combined effect of the Schuster mechanism and
radiative interlocking, and can be explained without the presence of
a chromosphere. Silicon absorption lines and the Lalpha profile set
constraints on the presence of a chromosphere, excluding a strong
temperature rise in layers deeper than tau_R ~ 10(-4) . Based on
observations with the NASA/ESA Hubble Space Telescope obtained at the
Space Telescope Science Institute, which is operated by AURA, Inc.,
under NASA contract NAS 5-26555.

---------------------------------------------------------
Title: Analysis of IUE Spectra of Λ Bootis Stars in the Framework
of New Quasi-Molecular Opacities
Authors: Allard, N.; Kurucz, R.; Gerbaldi, M.; Faraggiana, R.
1998ESASP.413..105A Altcode: 1998uabi.conf..105A
No abstract at ADS

---------------------------------------------------------
Title: LTE Models
Authors: Kurucz, R. L.
1998HiA....11..646K Altcode:
The author can compute arbitary-abundance models and spectra at
high resolution using millions of atomic and diatomic molecular
lines. Examples are given for Sakurai's object and for a λ Boo
star. The author is continuing to improve the input line data.

---------------------------------------------------------
Title: Acoustic and MHD Wave Energy Fluxes for Late-Type Stars
Authors: Musielak, Z. E.; Cuntz, M.; Ulmschneider, P.; Theurer, J.;
Kurucz, R.
1997AAS...191.1206M Altcode: 1997BAAS...29.1228M
The vast amount of observational data collected at wavelengths
ranging from X-rays to radio waves have indicated the ubiquity of
stellar chromospheres among late-type stars. In addition, there is
growing observational evidence for inhomogeneous and locally strong
magnetic fields in stellar atmospheres. It is reasonable to assume that
stellar magnetic inhomogeneities may be similar to the `flux tube'
structures observed in the solar atmosphere outside sunspots. If so,
two distinct components of stellar chromospheres must be recognized,
namely, non-magnetic component, where acoustic waves are responsible
for the heating, and magnetic component, where MHD tube waves supply
energy for the heating. To construct theoretical models of stellar
chromospheres (see paper by Cuntz et al. presented at this meeting),
it is necessary to know the amount of non-radiative energy generated
in stellar convective zones and carried by acoustic and MHD tube
waves through stellar photospheres. In this paper, we discuss the
correct status of computing acoustic and MHD wave energy fluxes for
the Sun and late-type dwarfs. Our calculations are based on grey LTE
mixing-length convection zone models and both linear and non-linear
theories of wave generation are used. New acoustic and MHD wave
energy fluxes are presented for stars of population I and II in the
range of effective temperatures T_eff 2000 - 10000 K and gravities
log g = 1 - 8. The turbulent flow field is represented by an extended
Kolmogorov spatial and modified Gaussian temporal energy spectrum. The
mixing-length parameter is varied in the range alpha = 1 - 2. We find
that the obtained acoustic wave energy strongly depend on stellar
chemical composition and that MHD fluxes show wide variations for a
given spectral type, variations which can be attributed to changes
in the stellar flux tube filling factor. We discuss the range of the
filling factor for which the calculated MHD fluxes may account for
the observed levels of chromospheric activity.

---------------------------------------------------------
Title: (Erratum) Notes on the convection in the ATLAS9 model
atmospheres.
Authors: Castelli, F.; Gratton, R. G.; Kurucz, R. L.
1997A&A...324..432C Altcode:
Erratum to Astron. Astrophys. 318, 841 (1997)

---------------------------------------------------------
Title: Fundamental parameters of Cepheids. IV. Radii and luminosities.
Authors: Bersier, D.; Burki, G.; Kurucz, R. L.
1997A&A...320..228B Altcode:
A temperature scale for Cepheids is presented, based on Geneva
photometry. It uses new atmosphere models computed at various values
of microturbulent velocity. The scale so-obtained is compared to other
ones and the importance of microturbulence effects is shown. This
calibration is applied to 20 Cepheids for which the variation of
microturbulence is known. The detailed variations of temperature and
gravity are derived. The behavior of the photometric gravity is in very
good agreement with the effective gravity (sum of GM/R^2^ and of the
derivative of the radial velocity). Thus static atmosphere models can
be used to describe the temperature and gravity variations in Cepheids
under the following conditions: i) the microturbulence has to be taken
into account, ii) the effective gravity must be considered instead of
the static gravity, iii) in some cases, a small phase interval around
minimum radius does not give reliable results. The temperature and
bolometric corrections are then used to derive radii and distances
via the Baade-Wesselink technique. The resulting Period-Radius and
Period-Luminosity relations are discussed. Our results compare very
well with similar analysis based on infra-red (JHK) photometry.

---------------------------------------------------------
Title: A calibration of Geneva photometry for B to G stars in terms
of Teff, log G and [M/H]
Authors: Kunzli, M.; North, P.; Kurucz, R. L.; Nicolet, B.
1997A&AS..122...51K Altcode:
We have used recent Kurucz models and numerous standard stars to improve
the calibration of the Geneva photometric system proposed a few years
ago. A new photometric diagram for the classification of intermediate
stars (8500 &lt;= Teff &lt;= 11000 K) is proposed and fills
a gap that the previous calibration had left open. Evidence is given
for a clear inadequacy of the new Kurucz models in the region of the
parameter space where convection begins to take over radiation in the
star's atmosphere. This problem makes the determination of the surface
gravity difficult, but leaves that of the other parameters apparently
unaffected. The determination of metallicity is considerably improved,
thanks to the homogeneous spectroscopic data published recently
by \cite[Edvardsson et al. (1993)]{ref23}. Instead of showing the
traditional diagrams, we chose to publish the diagrams of the physical
parameters with the inverted grids inside, i.e. the lines of constant
photometric parameters.

---------------------------------------------------------
Title: Notes on the convection in the ATLAS9 model atmospheres.
Authors: Castelli, F.; Gratton, R. G.; Kurucz, R. L.
1997A&A...318..841C Altcode:
The mixing-length theory for the convection, as it is used in the ATLAS9
code (Kurucz, 1993a), is summarized and discussed. We investigated
the effect of the modification called “approximate overshooting”
on the model structure of the Sun and of stars with T_eff_ included
between 4000K and 8500K, logg included between 2.5 and 4.5, and
metallicities [M/H]=0.0 and [M/H]=-3.0. We found that the Kurucz
solar model (SUNK94) with the “overshooting” option switched on
reproduces more observations than that without “overshooting”. In
the Hgamma_ and Hbeta_ regions no solar model
is able to reproduce the level of the true continuum deduced from
high-resolution observations absolutely calibrated. At 486 nm
the computed continuum is about 6.6% higher than that inferred
from the observed spectrum. We found that the largest effect of
the “approximate overshooting” on the model structure occurs
for models with T_eff_&gt;6250K and it decreases with decreasing
gravity. The differences in (b-y), (B-V), and (V-K) indices computed
from models with the “overshooting” option switched on and off,
correspond to T_eff_ differences which may amount up to 180K, 100K,
60K respectively. The differences in T_eff_ from Balmer profiles may
amount up to 340K and they occur also for T_eff_&lt;6250K down to
about 5000K. The c_1_ index yields gravity differences {DELTA}logg as
a function of logg which, for each T_eff_, grow to a maximum value. The
maximum {DELTA}logg decreases with increasing temperatures and ranges,
for solar metallicity, from 0.7 dex at logg=0.5 and T_eff_=5500K to
0.2dex at logg=4.5 and T_eff_=8000K. This behaviour does not change
for [M/H]=-3.0. Comparisons with the observations indicate that model
parameters derived with different methods are more consistent when the
“overshooting” option is switched off (NOVER models), except for the
Sun. In particular for Procyon, T_eff_ and logg from NOVER models are
closer to the parameters derived from model independent methods than are
T_eff_ and logg derived from the Kurucz (1995) grids. However, no model
is able to explain the whole observed spectrum of either the Sun or
Procyon with a unique T_eff_, regardless of whether the “overshooting”
option is switched on or off. Independently of the convection option,
the largest differences in T_eff_ derived with different methods are
of the order of 200K for Procyon and 150K for the Sun.

---------------------------------------------------------
Title: Progress on Model Atmospheres and Line Data (Invited Paper)
Authors: Kurucz, R. L.
1997ESASP.419..193K Altcode: 1997fiso.work..193K
I can compute arbitrary-abundance models and spectra at high resolution
using millions of atomic and diatomic molecular lines. I am improving
the input line data.

---------------------------------------------------------
Title: Model Atmospheres for Individual Stars with Arbitrary
Abundances
Authors: Kurucz, Robert L.
1997fbs..conf...33K Altcode: 1997LDP....22...33K
No abstract at ADS

---------------------------------------------------------
Title: Progress on model atmospheres and line data.
Authors: Kurucz, R. L.
1997IAUS..189..217K Altcode: 1998IAUS..189..217K
The author discusses errors in theory and in interpreting observations
that are produced by the failure to consider resolution in space,
time, and energy. He discusses convection in stellar model atmospheres
and in stars. One dimensional convective models can never work well,
but the errors in predicted diagnostics for temperature, gravity,
and abundances can be calibrated. The author discusses the variation
of microturbulent velocity with depth, effective temperature, and
gravity. These variations must be dealt with in computing models
and grids and in any type of photometric calibration. The author
describes the state of the art in computing a model atmosphere and
complete spectrum for stars with arbitrary abundances. He has made no
significant progress on atomic or molecular line data for the last two
years, but he will soon begin large scale production. He will continue
to distribute the results on CD-ROMs, and he will make them available
on the World Wide Web.

---------------------------------------------------------
Title: Progress on Model Atmospheres and Line Data.
Authors: Kurucz, R.
1997fsp..proc..217K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: VizieR Online Data Catalog: B to G stars calibration in Geneva
photometry (Kunzli+, 1997)
Authors: Kunzli, M.; North, P.; Kurucz, R. L.; Nicolet, B.
1996yCat..41220051K Altcode:
We have used recent Kurucz models and many standard stars to revise
previous calibrations of the Geneva photometric parameters in terms
of Teff, logg, and [M/H]. In addition, new parameters pT and pG
were defined, which are the Geneva equivalents of Stromgren's a
and r parameters and allow to estimate Teff and logg for stars with
intermediate temperature (spectral type A0-A3). A fortran code (calib.f)
has been written, which applies our calibration to stars measured in
the Geneva system. A conspicuous change in slope appears in the grid
d vs B2-V1. It seems to be linked with the onset of convection in the
superficial layers of the star's envelope. (1 data file).

---------------------------------------------------------
Title: VizieR Online Data Catalog: Semiempirical gf Values (Kurucz
+ 1975)
Authors: Kurucz, R. L.; Peytremann, E.
1996yCat.6010....0K Altcode:
This table of gf values for 265,587 atomic lines is selected from the
line data used to calculate line-blanketed model atmospheres (Kurucz
et al. 1974). The data are especially useful for line identification
and spectral synthesis in solar and stellar spectra. Except for 10,100
lines taken from the literature, the gf values have been calculated
semiempirically by using scaled Thomas-Fermi-Dirac radial wavefunctions
and eigenvectors found through least-squares fits to observed energy
levels. Included in the calculation were the first five or six stages
of ionization for sequences up through nickel. Published gf values
have been included for elements heavier than nickel. The tabulation is
restricted to lines with wavelengths less than 10um. (1 data file).

---------------------------------------------------------
Title: Research on Spectroscopy, Opacity, and Atmospheres
Authors: Kurucz, Robert L.; Bell, Barbara
1996sao..reptR....K Altcode:
This line list is a replacement for the Kurucz-Peytremann line list. We
have combined all the atomic files from CDROM 18 into 534910 line files
GFALL.DAT and GFELEM.DAT. These are the data we actually use to compute
spectra. They are not up to date. References are given in GFALL.REF
or GFELEN.REF. There are no references after 1988. For light elements
there are no references after 1979. We have the literature into the
1990's but have not had manpower or funding to update everything. Our
current plan is to make a new semiempirical calculation for each species
and at that time to include all the data from the literature. One new
development is the inclusion of hyperfine splitting for the iron group
elements using hyperfine data from the literature through 1993. The
data are very incomplete. We have not yet included data for isotopic
splitting. We supply a program for splitting the line list for a
species. It reads the hyperfine and isotopic splitting parameters for
levels and computes the oplittings whenever those levels appear. Lines
with no splitting data are copied untouched. Because Sc, Mn, and Co
are monoisotopic, only the hyperfine splittings are needed. Since 51V
is much more abundant than S0V, the isotope shifts are small for 51V,
and we approximate V with 51V. GFALLKYP.DAT has 754946 lines including
hyperfine Sc(I), V(I), Mn(I), and Co(I). A bibliography for last year
(1994-1995) is also attached.

---------------------------------------------------------
Title: On-line atomic &amp; molecular data for astronomy.
Authors: Smith, P. L.; Esmond, J. R.; Heise, C.; Kurucz, R. L.
1996uxsa.conf..513S Altcode: 1996uxsa.coll..513S
Very few of the atomic and molecular data used in analyses of
astronomical spectra are currently available in World Wide Web (WWW)
databases that are searchable with hypertext browsers. The authors
have begun to rectify this situation by making the extensive
atomic data files of R. L. Kurucz and R. L. Kelly available
with simple search procedures. They have also made a number of
other useful atomic and molecular data files available on the WWW
and have established links to other on-line atomic and molecular
databases. All can be accessed from the database homepage with URL:
http://cfa-www.harvard.edu/amp/amdata.html.

---------------------------------------------------------
Title: Status of the ATLAS 12 Opacity Sampling Program and of New
Programs for Rosseland and for Distribution Function Opacity
Authors: Kurucz, R. L.
1996ASPC..108..160K Altcode: 1996mass.conf..160K
No abstract at ADS

---------------------------------------------------------
Title: Model Stellar Atmospheres and Real Stellar Atmospheres
Authors: Kurucz, R. L.
1996ASPC..108....2K Altcode: 1996mass.conf....2K
No abstract at ADS

---------------------------------------------------------
Title: The UV Spectrum of Lambda Boo
Authors: Gerbaldi, M.; Gulati, R. K.; Faraggiana, R.; Kurucz, R. L.
1996ASPC..108..270G Altcode: 1996mass.conf..270G
No abstract at ADS

---------------------------------------------------------
Title: A new opacity-sampling model atmosphere program for arbitrary
abundances
Authors: Kurucz, R. L.
1996IAUS..176..523K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Research on Spectroscopy, Opacity, and Atmospheres
Authors: Kurucz, Robert L.
1996sao..reptS....K Altcode:
The main accomplishment was the merging of all the atomic line data
into one wavelength-sorted list that is simple to use. We have combined
all the atomic files from a CDROM into 534,910 line files GFALL.DAT and
GFELEN.DAT. These are the data we use to compute spectra. They are not
up to date. References are given in GFALL.REF or GFELEK.REF. There are
no references after 1988, and for light elements there are no references
after 1979. One new development is the inclusion of hyperfine splitting
for the iron group elements using hyperfine data from the literature
through 1993. The data are very incomplete. We have supplied a program
for splitting the line list for a species. It reads the hyperfine and
isotopic splitting parameters for levels and computes the splittings
whenever those levels appear. Lines with no splitting data are copied
untouched. Because Sc, Mn, and Co are monoisotopic, only the hyperfine
splittings are needed. Since 51V is much more abundant than 50V,
the isotope shifts are small for 51V, and we approximate V with
51V. GFALLHYP.DAT has 754,946 lines including hyperfine Sc I, V I,
Mn I, and Co I.

---------------------------------------------------------
Title: The Primordial Lithium Abundance
Authors: Kurucz, Robert L.
1995ApJ...452..102K Altcode:
The D lines of Li I in extreme Population II stars hotter than 5500
K are highly temperature sensitive because lithium is nearly all
ionized. A one-dimensional model atmosphere represents a space and
time average over the actual three-dimensional, moving, hot and
cold convective structure. Neutral Li does not have the average
behavior represented by the one-dimensional model. Lithium is
overionized by a factor of 10 so that the Li abundance computed from a
one-dimensional model is too small by this same factor. Consequently,
log (NLi/Ntotal) + 12 &gt; 3.0. This
higher Li abundance resolves the only discrepancy in the radiatively
driven cosmological model of the universe previously discussed by
Kurucz. Because the baryon density is high enough to produce a flat,
or nearly flat, universe, the number of stars can increase by a factor
of 10, and the amount of radiation given off by those stars in the first
billion years can increase by a factor of 10 over what is possible with
a low baryon density. This model can explain the formation of Population
III stars, globular clusters, galaxies, quasars, voids, galaxy clusters,
streaming, and large-scale structure. It can explain isolated galactic
evolution and morphology including bulges, disks, and abundances.

---------------------------------------------------------
Title: Synthetic DDO colours.
Authors: Morossi, C.; Franchini, M.; Malagnini, M. L.; Kurucz, R. L.
1995A&A...295..471M Altcode:
Calibrated synthetic DDO colours computed from Kurucz (1993) atmosphere
models and fluxes are presented. The transformation equations to make
synthetic colours consistent with the observational system are derived
by using a set of calibration stars for which atmosphere parameters
are known from high resolution spectroscopy. The synthetic C(45-48)
versus C(42-45) diagram is compared with observational sequences of
Population I giants and dwarfs and a good agreement is obtained. The
metallicity effect in the synthetic diagram is discussed. The obtained
results lead to the conclusion that synthetic calibrated DDO colours
are valuable tools for analysing Population I and II late-type stars
and for computing integrated colours of globular clusters and galaxies.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Theoretical Stellar Flux Spectra
for F- to K-type Stars (Buser+ 1992)
Authors: Buser, R.; Kurucz, R. L.
1995yCat.6078....0B Altcode:
In conjunction with Kurucz' (1979a,b) models for O to G stars,
the present models for F- to K- stars provide an extensive,
quasi-homogeneous grid of low-resolution theoretical flux spectra
for a significant range in stellar parameters covering mostly
of the observed HR diagram. The file bklate.dat contains 242
theoretical model atmosphere flux distributions for late-type
stars. These flux distributions were calculated by Buser &amp;
Kurucz in 1983-5 using published and unpublished models by Gustafsson
and his associates. Please refer to the publication (A&amp;A 264,
447) for a full description of the calculations and a discussion
of synthetic UBVRI photometry computed from these models. The
models cover the following ranges in the parameter space:
-----------------------------------------------------------
number fraction of hydrogen xH =0.9 all models turbulent
velocity [km/s] vturb =2.00 234 models vturb =5.00 8 models
-----------------------------------------------------------
3750 &lt;= Teff &lt;= 6000 (K) 0.75 &lt;= log.g
&lt;= 5.25 (cm/s/s) -3.00 &lt;= [Fe/H] &lt;= 0.50 (dex)
----------------------------------------------------------- Notice
that the model sequence does NOT strictly follow an orderly pattern in
parameter space, because the present file was composed from several
original files having their individual parameter sequences. The
last model (#242) is the solar model. Note that the present file
still contains 8 models (out of a total of 242) which have turbulent
velocities vturb=5.00 km/s, but whose flux distributions have n o t
actually been computed for this value of vturb (=5.00 km/s). Hence,
for these models, the flux distributions given in the present file are
erroneous and should not be used at all. It is suggested that the user
d e l e t e them from the file altogether; for the user's convenience,
these models are marked on the accompanying list. (1 data file).

---------------------------------------------------------
Title: The Spectrum of Sirius from 307 to 1040 NM
Authors: Furenlid, I.; Westin, T.; Kurucz, R. L.
1995ASPC...81..615F Altcode: 1995lahr.conf..615F
No abstract at ADS

---------------------------------------------------------
Title: Synthetic template spectra
Authors: Kurucz, R. L.
1995HiA....10..407K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Kurucz Smithsonian Atomic and Molecular Database
Authors: Kurucz, R. L.
1995ASPC...78..205K Altcode: 1995aapn.conf..205K
No abstract at ADS

---------------------------------------------------------
Title: Atomic Line Data
Authors: Kurucz, Robert; Bell, B.
1995KurCD..23.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Atomic line list
Authors: Kurucz, Robert L.; Bell, Barbara
1995all..book.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Solar Spectrum: Atlases and Line Identifications
Authors: Kurucz, R. L.
1995ASPC...81...17K Altcode: 1995lahr.conf...17K
No abstract at ADS

---------------------------------------------------------
Title: An Atomic and Molecular Data Bank for Stellar Spectroscopy
Authors: Kurucz, R. L.
1995ASPC...81..583K Altcode: 1995lahr.conf..583K
No abstract at ADS

---------------------------------------------------------
Title: The Kurucz (Smithsonian) atomic and molecular database
Authors: Kurucz, R. L.
1995HiA....10..579K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: An Upper Limit for the Deuterium Abundance in the Halo Star
HD 140283
Authors: Lubowich, D. A.; Pasachoff, Jay M.; Galloway, Robert P.;
Kurucz, R. L.; Smith, Verne V.
1994AAS...185.9805L Altcode: 1994BAAS...26.1479L
Because of the possible enhanced deuterium abundance of D/H =
2.5 10(-4) (the ISM D/H = 1.65x10(-5) ) recently reported in quasar
absorption spectra, we searched for the D_alpha line at 6561 A in the
metal-poor halo star HD 140283 (G2IV, [Fe/H] = -2.6; Teff=
5700K). We observed HD 140283 using the .9m KPNO coude feed and the
2.7m McDonald Observatory telescopes with echelle spectrographs
having a resolution Delta lambda = .05 A/pixel with S/N= 200 and
Delta lambda = .11 A/pixel with S/N = 600 respectively. We did not
detect the D_alpha line and compared our results to model atmosphere
calculations for this star. We estimate an upper limit of D/H &lt;
1x10(-5) which is smaller than the primordial or and Early Galactic
D/H = 8x10(-5) . Since D is destroyed via reactions with protons at T
&gt; 5x10(5) K, the atmospheric deuterium has probably been destroyed
during the pre-main sequence convection phase. Because (7) Li, (9)
Be, and (11) B have all been detected in this star (Li/H=1.5x10(-10)
and B/H=2.9x10(-12) ) and Li is destroyed at T &gt; 2.5x10(6) K, the
temperature at the bottom of the pre-main sequence convection zone is
1x10(6) K &lt; T &lt; 2.5x10(6) .K

---------------------------------------------------------
Title: Cross-correlation radial-velocity techniques for rotating
F stars.
Authors: Nordstroem, B.; Latham, David W.; Morse, Jon A.; Milone,
A. A. E.; Kurucz, R. L.; Andersen, J.; Stefanik, R. P.
1994A&A...287..338N Altcode:
Data reduction techniques for cross-correlation determination of
radial velocities for F stars using echelle spectra obtained with
the Center for Astrophysics Digital Speedometers are described and
evaluated. Synthetic spectra, calculated for a grid of spectral types
and rotational velocities, are used to derive radial velocities for
a large sample of nearby F stars with a wide range of rotational
velocities. Using a grid of calculated spectra provides a set of
noise-free templates on a consistent wavelength scale and allows
a closer match between the rotational velocity of the object and
that of the template spectrum than would be possible using observed
spectra as templates. We describe the methods used to choose the
template parameters for each star and the tests conducted to evaluate
the accuracy of our procedure. Typically the random error of a single
velocity measurement is in the range 0.7 to 3 km/s, depending primarily
on the rotation of the star. The zero point of our velocity system has
been established to an accuracy of better than 1km/s for the F stars.

---------------------------------------------------------
Title: Further Enhancements to the Wilson-Devinney Eclipsing Binary
Modeling Code
Authors: Milone, E. F.; Stagg, C. R.; Kallrath, J.; Kurucz, R. L.
1994AAS...184.0605M Altcode: 1994BAAS...26Q.867M
The enhancements to the Wilson-Devinney code described earlier (see
Milone et al., ApJS 79, 123, 1992 and Milone, ed., 'Light Curve Modeling
of Eclipsing Binary Stars' 1993) have been extended to the 1993 version
of the WD program and now involve the latest Kurucz atmospheres for a
range of metallicities. Potentially all of Kurucz' models may be used
to construct files of the ratio of the flux to blackbody curves for the
passbands of interest, if the passband profiles are known. The version
is called WD93K93. These improvements have also been extended to our
simplex version, LC93KS, which permits a sweep of parameter space for
deepest minimum and thus tests model uniqueness. Both codes now permit
spot modeling although WD93K93 is restricted to 4 parameters on each of
2 spots. Future work will involve attempts to improve the convergence
algorithms, global search capabilities, and efficiency. This work
is being supported by Canadian NSERC and University of Calgary URGC
Grants to EFM.

---------------------------------------------------------
Title: Atomic Data for Mn and Co.
Authors: Kurucz, Robert
1994KurCD..21.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Alpha Centauri A Revisited
Authors: Furenlid, I.; Kurucz, R. L.; Meylan, T.
1994ASPC...64..560F Altcode: 1994csss....8..560F
No abstract at ADS

---------------------------------------------------------
Title: Solar abundance model atmospheres for 0,1,2,4,8 km/s.
Authors: Kurucz, Robert
1994KurCD..19.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Atomic Data for Ca, Sc, Ti, V, and Cr.
Authors: Kurucz, Robert
1994KurCD..20.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Model atmospheres for Vega.
Authors: Castelli, F.; Kurucz, R. L.
1994A&A...281..817C Altcode:
We compared blanketed Local Thermodynamic Equilibrium (LTE) models
for Vega computed both with the opacity distribution function (ODF)
method and the opacity-sampling (OS) method. In the ODF case we used
the ATLAS9 code with the new opacity data from Kurucz (1992). Model
parameters for Vega depend on the amount of reddening and on the
helium abundance. For E(B-V) ranging from 0.0 to 0.01, the effective
temperature Teff is included between 9550K and 9650K. A lower
limit for the graity is log g = 3.95, obtained for Teff
= 9550K and solar He abundance. The metallicity is (M/H) = -0.5. The
parameters were fixed by comparing the observed ultraviolet, visual, and
near infrared flux distribution with the computed one and by comparing
observed and computed Balmer profiles. A microturbulent velocity zeta =
2 km/s was assumed on the basis of previous spectroscopic works. In
the OS case, we computed a model with parameters Teff =
9550K, log g = 3.95, zeta = 2 km/s, but with the real abundances of
Vega, as derived from spectroscopic analyses. We used the ATLAS12 code
(Kurucz 1993b). The comparison of the fluxes and Balmer profiles from
the ATLAS9 and ATLAS12 models computed with the same Teff,
log g, and zeta, but with different abundances for some elements has
shown that they are almost identical, small differences occuring only
in the ultraviolet. Therefore ATLAS9 fluxes can be used to predict
colors of Vega. The more realistic ATLAS12 models should be used as
starting point for abundance analyses and for spectrum synthesis.

---------------------------------------------------------
Title: Atomic Data for Fe and Ni.
Authors: Kurucz, Robert
1994KurCD..22.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Computation of Opacities for Diatomic Molecules
Authors: Kurucz, Robert L.
1994LNP...428..282K Altcode: 1994mse..conf..282K; 1994IAUCo.146..282K
No abstract at ADS

---------------------------------------------------------
Title: Synthetic Infrared Spectra
Authors: Kurucz, R. L.
1994IAUS..154..523K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A GHRS/HST Spectral Atlas of Sirius-A
Authors: Wahlgren, G. M.; Johansson, Se.; Kurucz, R. L.; Leckrone,
D. S.
1993AAS...183.1806W Altcode: 1993BAAS...25.1321W
The Goddard High Resolution Spectrograph (GHRS) onboard the Hubble
Space Telescope has been used to obtain a spectral atlas, covering the
wavelength range 1270 - 3200 Angstroms , of the bright star Sirius-A
(A1 V). The use of the GHRS first-order gratings provides spectral
resolutions between R = 20000 - 35000; however, the rotational velocity
(v sin i = 16 km sec(-1) ) limits the spectral resolution. The
signal-to-noise ratio over most of the spectrum is approximately
200 by photon statistics. The data are being used to understand the
ultraviolet line opacity in warm stars. As a result of this work a new
model atmosphere for Sirius will be determined, along with corrections
to its bolometric correction and elemental abundances. The spectrum
also allows us to test and improve current atomic models. A by-product
of our work will be more accurate wavelengths and oscillator strengths
for the second spectra of the iron-peak elements that will serve as
templates for studying the ultraviolet spectra, obtained at lower
spectral resolutions, of other warm stars.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Model atmospheres for Vega
(Castelli+ 1994)
Authors: Castelli, F.; Kurucz, R. L.
1993yCat..32810817C Altcode:
Not Available (10 data files).

---------------------------------------------------------
Title: VizieR Online Data Catalog: Model Atmospheres (Kurucz, 1979)
Authors: Kurucz, R. L.
1993yCat.6039....0K Altcode:
This tape lists fluxes and temperature-mass relations for 1200
models. The first 284 models are from Kurucz, R.L., Ap.J. Supp.,
40,1,1979 and are described there. Next are purely radiactive
models for A and B stars with Teff 8000K to 20000K for [M/H]
=-1.,-.5,+.5,+1. Finally are new improved convective models for 5500K to
8500K with [M/H]=+1.,+.5,0.,-.5,-1.,-1.5, -2.,-2.5,-3.,-9.99. Because
the new models have not yet been published and because I am computing
visible and infrared colors in various photometric systems, these new
fluxes should not be used to publish colors without my agreement. For
any other use these fluxes are in the public domain. The models are
presented as ATLAS format input decks. The tape is recorded on 9 tracks
at 1600 bpi in ASCII card images with 4000 character blocks. A sample
program that reads the tape follows. I suggest that the user read the
tape once and write a binary tape that can be read much more quickly. (1
data file).

---------------------------------------------------------
Title: The Mount Wilson Observatory Metallicity Index, C RV:
Comparison with Other Photometric Systems
Authors: Soon, W. H.; Zhang, Q.; Baliunas, S. L.; Kurucz, R. L.
1993ApJ...416..787S Altcode:
A new spectrophotometric index, CRV, is assessed as a
metallicity indicator for late-type stars. The index is the ratio of
the measured photospheric fluxes in 20 Å wide passbands centered
at 400t and 3901 Å. CRV correlates directly with the
metallicity index, m1, of the Strömgren uvby system and
with the metallicity index hk, of Anthony-Twarog et al. (1991). Using observations of 236 dwarfs and 140 giants combined with
stellar atmosphere models (Kurucz 1991), we compared the sensitivity
of the CRV, m1, and hk indices to metal
abundance. We also studied the sensitivity of the CRV,
C1, and hk indices to surface gravity. The effect of
interstellar extinction on all the indices was also studied from
published mean extinction laws. We find that the CRV
index is sensitive to the variation of metal abundance, [M], over the
range examined (-5.0 ≲ [M] ≲ 0.5). CRV is also more
sensitive than the m1 index at metal-poor conditions ([M]
≲ -2.0). The CRV index has the following advantages: (1)
the passbands of CRV are dominated by Fe lines, which reduce
the uncertainty that may be introduced by the presence of lines of
α-process elements with enhanced abundances at metal-poor conditions;
(2) the effect of interstellar reddening is limited because the two
passbands are separated in wavelength by only 100 Å. We also find
that the atmospheric models produce results that agree qualitatively
with the trends of observed indices on stellar parameters such as
effective temperature, metallicity, and surface gravity.

---------------------------------------------------------
Title: Cool stars : spectral energy distributions and model atmosphere
fluxes.
Authors: Morossi, C.; Franchini, M.; Malagnini, M. L.; Kurucz, R. L.;
Buser, R.
1993A&A...277..173M Altcode:
The main results of a program of systematic comparison between observed
and computed spectral energy distributions of late G and K type solar
chemical composition stars are illustrated. We built the observed energy
distributions of eleven representative stars, from the ultraviolet to
the infrared, starting from lUE archive data, supplemented by our own
lUE observations, and data from the literature. Broad-band Johnson
and DDO color indices, together with suitable calibrations, were
used for estimating the basic stellar atmospheric parameters, i.e.,
effective temperature and surface gravity. Theoretical fluxes were
computed for the appropriate parameters of each star, starting from
a recent grid of atmosphere models. While very good consistency
between data and model predictions has been obtained in the optical and
infrared, significant discrepancies were found in the ultraviolet. We present semi-empirical models, based on the minimum temperature
concept, obtained by modifying the temperature (versus optical depth)
structure so as to mimic the effect of non-radiative heating in the
upper photospheres of cool stars. The fluxes predicted by these models
provide a fairly good description of the data not only in the visible
and IR regions, but also in the ultraviolet region. Our results indicate
that different values for the Tmin/Teff ratio,
ranging from 0.76 (as in the Sun) up to 0.85 (θ Boo), are required
to reproduce the observed ultraviolet fluxes of different stars.

---------------------------------------------------------
Title: A Critical List of Voigt-fitted Equivalent Width Measurements
Based on the Solar Flux Spectrum
Authors: Meylan, Thomas; Furenlid, Ingemar; Wiggs, Michael S.; Kurucz,
R. L.
1993ApJS...85..163M Altcode:
Equivalent widths of around 570 carefully selected absorption lines in
the solar flux spectrum have been measured, using the Solar Flux Atlas
from 296 to 1300 nm by Kurucz et al. (1984). The equivalent widths were
derived from Voigt functions fitted to the selected line profiles in
the Solar Flux Atlas. The measurements were used to determine two sets
of solar log gf-values; one set is based on the solar model in the 1979
model grid by Kurucz and the other set on a similar 1990 solar model,
also by Kurucz, using revised metal abundances by Anders and Grevesse
(1989). The data provide a homogeneous, high-precision reference for
studies of differential stellar abundances based on equivalent widths,
using the solar flux spectrum as the standard.

---------------------------------------------------------
Title: The Nonsolar Abundance Ratios of Arcturus Deduced from
Spectrum Synthesis
Authors: Peterson, Ruth C.; Dalle Ore, Cristina M.; Kurucz, Robert L.
1993ApJ...404..333P Altcode:
Using opacity distribution functions based on a newly expanded atomic
and molecular line list, we have calculated a model atmosphere for
Arcturus that reproduces the observed flux distribution. Individual
line parameters in teh list were adjusted to match the solar spectrum
in a preliminary way, in the regions 5000-5500 A, 6000-6500 A,
and 7500-9000 A. The Arcturus model spectrum calculated with these
adjustments reproduces well the profiles of all lines in the observed
spectrum of the Griffin atlas for which the solar gf-values are
well determined. The Arcturus model has an iron abundance (Fe/H) =
-0.5 +/- 0.1, a temperature T(eff) = 4300 +/- 30 K, gravity log g =
1.5 +/- 0.15, and an overabundance of the light metals. The factor of
two enhancement in Arcturus of O, Mg, Si, Ca, and Ti is similar to
that of halo stars of much lower metallicity and velocity about the
Galactic center. This enhancement significantly affects the ionization
equilibria and opacities of Arcturus.

---------------------------------------------------------
Title: New calibration of the Vilnius photometric system. I. Effective
temperatures and gravities of B-type stars.
Authors: Straizys, V.; Kurucz, R. L.; Philip, A. G. D.; Valiagua, G.
1993BaltA...2..326S Altcode: 1993OAst....2..326S
Color indices and reddening-free Q-parameters in the Vilnius photometric
system of B-type stars of all luminosities and A-supergiants are
calibrated in terms of effective temperature and surface gravity,
using synthetic spectra of the newest Kurucz model atmospheres. The
calibration is verified by comparing the photometrically determined
effective temperatures and surface gravities with the most accurate
spectroscopic data. Satisfactory agreement has been found, proving the
accuracy of the calibration within +/- 0.02 to +/- 0.05 dex in log Te
and +/- 0.2 to +/- 0.3 dex in log g.

---------------------------------------------------------
Title: Atomic data for opacity calculations.
Authors: Kurucz, Robert
1993KurCD...1.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: ATLAS9 Stellar Atmosphere Programs and 2 km/s grid.
Authors: Kurucz, Robert
1993KurCD..13.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: SYNTHE Spectrum Synthesis Programs and Line Data.
Authors: Kurucz, Robert
1993KurCD..18.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Diatomic Molecular Data for Opacity Calculations.
Authors: Kurucz, Robert
1993KurCD..15.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Opacities for Stellar Atmospheres: [-2.5a],[-3.0a],[-3.5a]
+.4 alpha.
Authors: Kurucz, Robert
1993KurCD..11.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Atomic data for interpreting stellar spectra: isotopic and
hyperfine data.
Authors: Kurucz, R. L.
1993PhST...47..110K Altcode:
The quality of solar, stellar, and interstellar observations is now
so high that we can see physical effects that have been assumed to
be insignificant. In natural isotopic mixtures essentially all atomic
lines are asymmetric because of isotopic and hyperfine components. In
astrophysics the effects of isotopic components have been generally
ignored in the case of Ti, Cr, Fe and Ni. Ignoring isotopic splitting
introduces systematic errors. It is imperative that laboratory
measurements be made to determine the isotopic splitting of every
energy level of every stable isotope of every atom and ion as is now
routinely done for actinides and for diatomic molecules. Hyperfine
splitting should be measured as well for those isotopes with nuclear
spin. Computer programs for analyzing spectra including the hyperfine
and isotopic splitting already exist. One now need the laboratory data.

---------------------------------------------------------
Title: Opacities for Stellar Atmospheres: [-4.0a],[-4.5a],[-5.0a]
+.4 alpha
Authors: Kurucz, Robert
1993KurCD..12.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A New Opacity-Sampling Model Atmosphere Program for Arbitrary
Abundances
Authors: Kurucz, R. L.
1993ASPC...44...87K Altcode: 1993pvnp.conf...87K; 1993IAUCo.138...87K
No abstract at ADS

---------------------------------------------------------
Title: Opacities for Stellar Atmospheres: [+0.5a],[+0.0a],[-0.5a]
+.4 alpha.
Authors: Kurucz, Robert
1993KurCD...9.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Opacities for Stellar Atmospheres:
[-5.0],[+0.0,noHe],[-0.5,noHe].
Authors: Kurucz, Robert
1993KurCD...8.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Opacities for Stellar Atmospheres: Abundance Sampler.
Authors: Kurucz, Robert
1993KurCD..14.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Opacities for Stellar Atmospheres: [-0.1],[-0.2],[-0.3]
Authors: Kurucz, Robert
1993KurCD...6.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Opacities for Stellar Atmospheres: [-2.0],[-2.5],[-3.0].
Authors: Kurucz, Robert
1993KurCD...4.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Models for VEGA
Authors: Castelli, F.; Kurucz, R. L.
1993ASPC...44..496C Altcode: 1993IAUCo.138..496C; 1993pvnp.conf..496C
No abstract at ADS

---------------------------------------------------------
Title: New atmospheres for modelling binaries and disks.
Authors: Kurucz, R. L.
1993IAUCB..21...93K Altcode:
The authors has used his newly calculated iron group line list
together with earlier atomic and molecular line data, 58,000,000 lines
total, to compute new opacities for the temperature range 2000K to
200000K. Calculations have been completed for a lot of of temperatures,
pressures, microturbulent velocities and scaled solar abundances. The
author has rewritten his model atmosphere program to use the new
line opacities, additional continuous opacities, and an approximate
treatment of convective overshooting. Thus far he has completed a grid
of 7000 model atmospheres at 2 km/s for all the abundances, for the
temperature range 3500K to 50000K, and for log g from 0.0 to 5.0. The
models, fluxes, intensities, and colors are available on magnetic tape
and will also be distributed on CD-ROMs.

---------------------------------------------------------
Title: Opacities for Stellar Atmospheres: [+0.1],[+0.2],[+0.3].
Authors: Kurucz, Robert
1993KurCD...5.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Opacities for Stellar Atmospheres: [-0.5],[-1.0],[-1.5].
Authors: Kurucz, Robert
1993KurCD...3.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Opacities for Stellar Atmospheres: [-3.5],[-4.0],[-4.5].
Authors: Kurucz, Robert
1993KurCD...7.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Opacities for Stellar Atmospheres: [+0.0],[+0.5],[+1.0].
Authors: Kurucz, Robert
1993KurCD...2.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Limbdarkening for 2 km/s grid (No. 13): [+1.0] to [-1.0].
Authors: Kurucz, Robert
1993KurCD..16.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Opacities for Stellar Atmospheres: [-1.0a],[-1.5a],[-2.0a]
+.4 alpha.
Authors: Kurucz, Robert
1993KurCD..10.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Limbdarkening for 2 km/s grid (No. 13): [+0.0] to [-5.0].
Authors: Kurucz, Robert
1993KurCD..17.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: SYNTHE spectrum synthesis programs and line data
Authors: Kurucz, Robert L.
1993sssp.book.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A library of theoretical stellar flux spectra. I. Synthetic
UBVRI photometry and the metallicity scale for F- to K-type stars.
Authors: Buser, Roland; Kurucz, Robert L.
1992A&A...264..557B Altcode:
Synthetic colors on the Johnson-Cousins standard UBVRI system of a
grid of theoretical model atmosphere flux distributions for late-type
stars are presented. These colors are based on new synthetic spectra
calculated from the flux-constant, blanketed model atmospheres of
Gustafsson et al. (1975) and Eriksson et al. (1979). The present
calculations substantially reduce the systematic effects of the 'missing
UV opacity' present in the synthetic colors computed by Bell &amp;
Gustafsson (1978) and by VandenBerg &amp; Bell (1985), who employed the
same models but different opacity source input. The new fluxes provide
significantly improved theoretical representations of the observed
two-color diagrams and the empirical temperature calibrations for F-,
G-, and K-type stars of all luminosities and metallicities. The present
models for F- to K-stars provide an extensive quasi-homogeneous grid
of low-resolution theoretical flux spectra for a significant range in
stellar parameters covering most of the observed HR diagram.

---------------------------------------------------------
Title: UV Spectra of K Type Stars from IUE Database
Authors: Morossi, C.; Franchini, M.; Malagnini, M. L.; Kurucz, R. L.
1992ESOC...43..381M Altcode: 1992ald2.proc..381M
No abstract at ADS

---------------------------------------------------------
Title: Atomic and Diatomic Molecular Opacities for Atmospheres
and Envelopes
Authors: Kurucz, R. L.
1992AAS...180.3202K Altcode: 1992BAAS...24Q.779K
No abstract at ADS

---------------------------------------------------------
Title: Atomic and Molecular Data for Opacity Calculations
Authors: Kurucz, R. L.
1992RMxAA..23...45K Altcode:
I am attempting to produce line lists for all atoms and diatomic
molecules that are important in stars. I collect all published data
on spectrum analysis and oscillator strengths. I compute the energy
levels, wavelengths, gf values, and damping constants that are not
available from the literature. Line lists have been computed for
diatomic molecules H2, CII, NH, OH, MgH, SiH, CN, C2, CO, SiO, and TiO,
and for the iron group atoms Ca 1-IX to Ni 1-IX. These lists total 58
million lines. These calculations are being revised as new laboratory
data become available. The work is being extended to other diatomic
molecules, to lighter and heavier elements, and to higher stages
of ionization. Key words: ATOMIC PROCESSES - MOLECULAR PROCESSES -
TRANSITION PROBABILITIES

---------------------------------------------------------
Title: Remaining Line Opacity Problems for the Solar Spectrum
Authors: Kurucz, R. L.
1992RMxAA..23..187K Altcode:
We need high-resolution, high-signal-to-noise spectra of the sun with
complete spectral coverage. The solar spectrum provides the insolation
that controls the atmospheric chemistry of the earth and of all the
solar system bodies. It is important for stellar astrophysics as
the "standard" stellar spectrum because it can be observed better
than that of any other star. It is important for understanding the
sun, for it allows us to study the conditions and motions at its
surface. It is an important high-temperature laboratory source for
atomic and molecular spectroscopy. To interpret the spectrum we require
accurate energy levels, accurate wavelengths, accurate gf values,
accurate damping constants. We require hyperfine splitting, isotopic
splitting, and Zeeman splitting. We require completeness in order to
deconvolve blends. We need every level below the lowest ionization
or dissociation energy. For molecules that is every vibrational and
rotational level. Key words: ATOMIC PROCESSES - MOLECULAR PROCESSES -
TRANSITION PROBABILITIES - SUN: SPECTRA

---------------------------------------------------------
Title: "Finding" the "missing" solar ultraviolet opacity.
Authors: Kurucz, R. L.
1992RMxAA..23..181K Altcode:
The author has computed new opacities for model stellar atmospheres
and envelopes using a large grant of Cray computer time at the San
Diego Supercomputer Center. The opacities include 58,000,000 atomic
and diatomic molecular lines. Twelve-step distribution functions are
tabulated for 56 temperatures in the range from 2000 K to 200000 K,
for 21 log pressures from -2 to 8, for 1212 wavelength intervals from
10 to 10000 nm, for microturbulent velocities 0, 1, 2, 4, and 8 km/s,
for scaled solar abundances [+1.0], [+0.5], [+0.3], [+0.2], [+0.1],
[+0.0], [-0.1], [-0.2], [-0.3], [-0.5], [-1.0], [-1.5], [-2.0], [-2.5],
[-3.0], [-3.5], [-4.0], [-4.5], [-5.0], and [+0.0, no He] (log abundance
of elements heavier than helium relative to solar). Rosseland means
are also tabulated for each case. The final files for each abundance
require two 6250 bpi VAX backup tapes. The author is now distributing
tape copies. He hopes to have CD-ROMs available in the near future. A
solar photospheric model computed with the new opacities matches the
observed energy distribution.

---------------------------------------------------------
Title: The Eclipsing Binary AI Phoenicis: New Results Based on an
Improved Light Curve Analysis Program
Authors: Milone, E. F.; Stagg, C. R.; Kurucz, R. L.
1992ApJS...79..123M Altcode:
A revised atmospheres option based on the model developed by Kurucz
(1979) together with empirical correction factors are used to model
the parameters of AI Phe with the program of Wilson and Devinney
(1971), employing a single temperature to parameterize all light
curves from the UV to the IR, with better agreement with observation
than previous attempts applying this mode. Improved precision in
coupled luminosity-temperature determinations is obtained, especially
in fitting to the ground-based UV. The present fittings to IUE data
suggest nonlinear limb darkening for the primary component. The limb
darkening of the hotter component in the far UV as it undergoes total
eclipse is investigated and compared with Kurucz models.

---------------------------------------------------------
Title: Model Atmospheres for Population Synthesis
Authors: Kurucz, R. L.
1992IAUS..149..225K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Gedanken Astrophysics - the Universe Since Recombination
Authors: Kurucz, R. L.
1992ComAp..16....1K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The solar abundance of iron - A 'final' word.
Authors: Biemont, E.; Baudoux, M.; Kurucz, R. L.; Ansbacher, W.;
Pinnington, E. H.
1991A&A...249..539B Altcode:
New accurate radiative lifetimes have been measured by a
laser-induced-fluorescence technique for 12 selected levels of Fe(+)
of astrophysical interest. These new results combined with recent
theoretical transition probabilities provide another contribution in
order to try to solve the controversy concerning the content of iron
in the sun. The abundance value, A(Fe) = 7.54 +/-0.03, obtained from
an extensive sample of Fe II lines, supports the 'low' value of the
iron abundance, in agreement with the meteoritic result.

---------------------------------------------------------
Title: The SDSC Grid from [-5] to [+1] at 2 km/s
Authors: Kurucz, R. L.
1991BAAS...23..967K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A New Theoretical Model Photosphere
Authors: Kurucz, R. L.
1991BAAS...23.1047K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The solar spectrum.
Authors: Kurucz, Robert L.
1991sia..book..663K Altcode:
This chapter contains a discussion of what is known about the solar
spectrum as a whole from the ultraviolet to the infrared. The data
that are available are described and information is provided on how
the reader can obtain paper or magnetic tape copies for particular
applications, be it in atomic or molecular spectroscopy, or in solar,
atmospheric, planetary, cometary or stellar physics.

---------------------------------------------------------
Title: New Opacity Calculations
Authors: Kurucz, R. L.
1991ASIC..341..441K Altcode: 1991sabc.conf..441K
No abstract at ADS

---------------------------------------------------------
Title: New Lines, New Models, New Colors
Authors: Kurucz, Robert L.
1991ppag.conf...27K Altcode: 1991LDP....14...27K; 1991ppag.proc...27K
No abstract at ADS

---------------------------------------------------------
Title: Binaries among the blue stragglers in M67.
Authors: Milone, Alejandra A. E.; Latham, David W.; Kurucz, Robert L.;
Morse, Jon A.
1991ASPC...13..424M Altcode: 1991fesc.book..424M
The authors have used calculated spectra as templates to derive
radial velocities for eleven of the classical blue stragglers in M67
by cross-correlations. The mean velocities for all eleven stars are
close to the cluster mean, thus confirming their membership in the
cluster. For the blue straggler F190 they derive a spectroscopic
orbit with period 4.1829 d, eccentricity 0.21, and mass function
1.6×10-3Msun. Thus F190 is a good
candidate for a blue straggler that resulted from mass transfer in a
close binary. Several of the other blue stragglers show evidence for
low-amplitude velocity variations.

---------------------------------------------------------
Title: Relative Abundance Determinations in Extremely Metal Poor
Giants. II. Transition Probabilities and the Abundance Determinations
Authors: Peterson, Ruth C.; Kurucz, Robert L.; Carney, Bruce W.
1990ApJ...350..173P Altcode:
The abundances of Fe and other elements are determined for a star of
intermediate metallicity and for nine extremely metal poor stars,
including two members of the globular cluster M92 and CD -38 deg
245. The accuracy of the transition probabilities for Fe I and
other elements is evaluated. The distribution of the abundances of
other elements with respect to Fe is the same for most of the cases
studied. Manganese is the only element that shows a different relative
abundance in an extremely metal poor star.

---------------------------------------------------------
Title: High resolution ultraviolet stellar spectroscopy from space
observations: What atomic physics and astrophysics can do for
each other
Authors: Leckrone, D. S.; Johansson, Se.; Kurucz, R. L.; Adelman, S. J.
1990asos.conf....3L Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Why I study the solar spectrum
Authors: Kurucz, R. L.
1990asos.conf...20K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: High Resolution Ultraviolet Stellar Spectroscopy From Space
Observatories - Atomic Physics and Astrophysics
Authors: Leckrone, D. S.; Johansson, S.; Kurucz, R. L.; Adelman, S. J.
1989BAAS...21.1198L Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Reducing Photometry by Computing Atmospheric Transmission
Authors: Kurucz, Robert L.
1989LNP...341...55K Altcode: 1989ies..conf...55K
The transmission spectrum of the earth's atmosphere at every observatory
can be computed if monitors are set up to determine the atmospheric
structure and the abundance versus height of components that vary,
such as water vapor and particulates. Photometric observations can be
modelled and reduced using the measured instrumental bandpasses and the
computed transmission. This method of reduction will greatly improve
the quality of infrared photometry and may even be relevant in the
visible where ozone, oxygen dimer, and water vapor affect photometric
bandpasses. Here I describe the beginning of my work on this approach.

---------------------------------------------------------
Title: Effects of CO molecules on the outer solar atmosphere -
Dynamical models with opacity distribution functions
Authors: Muchmore, D.; Ulmschneider, P.; Kurucz, R. L.
1988A&A...201..138M Altcode:
Carbon monoxide can be an important cooling agent in late-type
stars. This paper expands previous theoretical work by extending the
frequency set used in the radiation calculations, employing opacity
distribution functions for the infrared bands of CO and 19 frequency
points for the H(-) continuum. It is found that the net cooling rate
due to CO decreases by a factor of about 3 due to the large optical
depths in the line cores. The influence of the 2.2-micron CO band is
small compared to the effect of the 4.6-micron band. An atmospheric
structure with a sharp drop of the temperature in the outer photosphere,
where CO cooling sets in, was found again. This temperature drop occurs
higher in the atmosphere and is less steep than in the simpler models
but is nevertheless steep enough to be convectively unstable. When CO
cooling sets in, surface temperatures drop to very low values (T less
than 3000 K) for radiative equilibrium models, even without including
the effects of other molecules.

---------------------------------------------------------
Title: Line-Blanketing in Theoretical Model Atmospheres for f, g,
and K-Type Stars
Authors: Buser, R.; Kurucz, R. L.
1988IAUS..132..531B Altcode:
The authors have computed improved flux distributions from Gustafsson
et al.'s (1979) extensive grids of theoretical model atmospheres
for late-type (F-K) giant and dwarf stars. The massive list of
atomic opacity sources used for the hotter Kurucz models was also
employed in calculating the cooler spectra. For both the giant and
the dwarf models, the resulting synthetic UBVRI photometry provides
excellent matches to the spectroscopic calibrations of the observed
metallicity and temperature scales based on the ultraviolet excesses,
δ(U-B), and the BVRI colors, respectively. The authors conclude that
the atomic line-blanketing accounts for the largest fraction of the
systematic UV discrepancy existing between observations and earlier
model calculations.

---------------------------------------------------------
Title: The Distances to RR Lyrae Variables
Authors: Jones, Rodney V.; Carney, Bruce W.; Latham, David W.; Kurucz,
Robert L.
1988IAUS..126..589J Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Metallicity Distribution Function of Halo Dwarfs and
Globular Clusters
Authors: Laird, J. B.; Rupen, M. P.; Carney, B. W.; Latham, D. W.;
Kurucz, R. L.
1988IAUS..126..517L Altcode:
Metallicities have been determined for a chemically unbiased sample
of field halo dwarf stars. Their metallicity distribution function is
similar to the predictions of a simple model of chemical evolution,
but somewhat different from that of globular clusters.

---------------------------------------------------------
Title: Yet another Progress Report - New Model Atmospheres Soon
Authors: Kurucz, R. L.
1988nds..conf...25K Altcode: 1988LDP.....9...25K
No abstract at ADS

---------------------------------------------------------
Title: Yet another Progress Report - New Models Soon
Authors: Kurucz, R. L.
1988csa..proc..139K Altcode: 1988LDP....10..139K
No abstract at ADS

---------------------------------------------------------
Title: Semiempirical Determination of Feii Oscillator Strengths
Authors: Kurucz, R. L.
1988ASSL..138...41K Altcode: 1988IAUCo..94...41K; 1988pffl.proc...41K
The "missing ultraviolet opacity" is caused by lines of iron group
elements that go to excited configurations that have not yet been
seen in the laboratory. For the first 10 ions the author computes
allowed and forbidden transition arrays for all known even and odd
configurations plus as many predicted configurations as he can fit in
the computer. A-sums, Stark and van der Waals broadening constants,
and the Lande g value are computed for each energy level.

---------------------------------------------------------
Title: OH and CH Continuous Opacity in Solar and Stellar Atmospheres
Authors: Kurucz, Robert L.; van Dishoeck, Ewine F.; Tarafdar, S. P.
1987ApJ...322..992K Altcode:
Continuous absorption cross sections of OH and CH have been computed
for the temperature range 1000K to 9000K. Both OH and CH produce
significant ultraviolet opacity in the Sun and cool stars. CH is also
significant in the visible at 400 nm.

---------------------------------------------------------
Title: A Survey of Proper-Motion Stars. II. Extracting Metallicities
from High-Resolution, Low S/N Spectra
Authors: Carney, Bruce W.; Laird, John B.; Latham, David W.; Kurucz,
Robert L.
1987AJ.....94.1066C Altcode:
The authors discuss the calculations of a grid of high-resolution
synthetic spectra covering λλ5150 - 5250, Teff = 4750,
5000, ..., 6500K, [M/H] = +0.5, 0, ..., -3.0, and gravities of log g
= 4.5 or 4.0. They describe a method using χ2 fits with
these spectra as templates in the determination of mean line strengths
from observed spectra. The authors estimate metallicities for 48 stars
whose abundances have been previously determined from high-resolution,
high-S/N spectra and conventional fine-analysis techniques. None of the
observed spectra are high S/N, yet they result in metallicities with
internal scatter of typically 0.1 dex. Comparison with published fine
analyses shows excellent agreement (-0.03±0.02 dex) for metal-poor
stars, and a small systematic error at higher abundances, which is
easily corrected. Metallicities with σ &lt; 0.2 dex are still obtained
even when S/N is as low as 3.

---------------------------------------------------------
Title: The Baade-Wesselink Method and the Distances to RR Lyrae
Stars. III. The Field Star SW Draconis
Authors: Jones, Rodney V.; Carney, Bruce W.; Latham, David W.; Kurucz,
Robert L.
1987ApJ...314..605J Altcode:
The authors have obtained simultaneous BV and JHK photometry and
radial velocities of typical accuracies of 1 km s-1 for the
moderately metal-rich ([Fe/H] ≈ -0.75) RRab star SW Draconis. They
have used these data and the surface brightness variation of the
Baade-Wesselink method to derive &lt;MV&gt; = +0.94±0.15
mag for this star. The phasing problem encountered earlier recurs
for SW Dra when the B-V index is employed. The authors find that SW
Dra is only 0.06±0.10 mag fainter than the very metal-poor ([Fe/H]
≈ -2.2) star X Ari, so that the two stars have essentially the same
luminosity within the uncertainty despite their large differences in
metallicity.The implication of this result upon the derived ages of
globular clusters is discussed.

---------------------------------------------------------
Title: The Baade-Wesselink Method and the Distances to RR Lyrae
Stars. II. The Field Star X ARIETIS
Authors: Jones, Rodney V.; Carney, Bruce W.; Latham, David W.; Kurucz,
Robert L.
1987ApJ...312..254J Altcode:
VR and JHK photometry and radial velocities with typical accuracies
of 1 km/sec for the metal-poor RR Lyrae field star X Arietis. These
data, along with unpublished UVBY photometry, have been used to derive
the distance to X Ari using two variations of the Baade-Wesselink
method. The possibility of photospheric velocity gradients that might
distort the value of the systemic velocity and cause a phase shift was
examined, and it was found that no gradient exists in the part of the
stellar atmosphere considered. The phasing problem previously noted for
VY Ser by Carney and Latham (1984) also occurs for X Ari when optical
photometry is used to compute the effective temperatures, but not when
the V - K color index is used. Possible causes of these phase shifts
are discussed, and it is concluded that X Ari has an aggregate average
V magnitude of 0.73-1.03 mag on the basis of the V - K results.

---------------------------------------------------------
Title: Atmospheres for population II stars.
Authors: Kurucz, Robert L.
1987fbs..conf..129K Altcode: 1987IAUCo..95..129K; 1987LDP.....8..129K
Recent theoretical models of stellar atmospheres are examined in a brief
critical review, with a focus on population II stars. Consideration
is given to numerical errors, physically inconsistent modeling
of convection, inadequate treatment of structural equilibrium,
arbitrarily selected microturbulent velocities and He abundances,
and underestimated Fe-group line opacities. Tables illustrating the
complexity of the model computations and listing corrected values of
key parameters are provided.

---------------------------------------------------------
Title: The Distances and Absolute Magnitudes of RR Lyrae Variables
Authors: Jones, R. V.; Carney, B. W.; Latham, D. W.; Kurucz, R. L.
1986BAAS...18..912J Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A New Sunspot Umbral Model and Its Variation with the Solar
Cycle
Authors: Maltby, P.; Avrett, E. H.; Carlsson, M.; Kjeldseth-Moe, O.;
Kurucz, R. L.; Loeser, R.
1986ApJ...306..284M Altcode:
Semiempirical model atmospheres are presented for the darkest parts of
large sunspot umbrae, regions have called umbral cores. The approach is
based on general-purpose computational procedures that are applicable
to different types of stellar atmospheres. It is shown that recent
umbral intensity measurements of the spectral energy distribution may
be accounted for by an umbral core atmospheric model that varies with
time during the solar cycle; the observed center-limb variation can be
accounted for by the properties of the model. Three umbral core models
are presented, corresponding to the early, middle, and late phases of
the solar cycle. These three models also may be regarded as having the
properties of dark, average, and bright umbral cores respectively. The
effects of atomic, opacity, and abundance data uncertainties on
the model calculations are briefly discussed. For comparison, a new
reference model for the average quiet solar photosphere is given.

---------------------------------------------------------
Title: Theoretical UVBY beta Indices
Authors: Lester, J. B.; Gray, R. O.; Kurucz, R. L.
1986ApJS...61..509L Altcode:
The authors present theoretical photometric indices on the Strömgren
and β systems for the published and unpublished grids of Kurucz. The
indices have been placed on the standard systems using the ultraviolet
and visual energy distributions of the secondary spectrophotometric
standards. The common practice of using a single standard star to
effect the transformation of the computed indices to the standard
system is shown to produce systematic errors.

---------------------------------------------------------
Title: The empirical BC versus T EFF scale for non-supergiant
O9-G5 stars.
Authors: Malagnini, M. L.; Morossi, C.; Rossi, L.; Kurucz, R. L.
1986A&A...162..140M Altcode:
By the analysis of observed energy distributions extending from the UV
to the IR, the effective temperature, the gravity and the bolometric
correction for a representative sample of nonsupergiant and not
chemically peculiar O9-G5 stars are derived in a self-consistent
way. The new, improved relationship between the bolometric
correction and the effective temperature is then compared to the
theoretical or observed ones previously published. The method used
permits the derivation of angular diameters for the stars, with an
uncertainty on the same order as the errors quoted for interferometric
measurements. The importance of these results in the calibration
of stellar parameters is stressed and their relevance for a direct
comparison between the theoretical and the observational HR diagrams
is briefly mentioned.

---------------------------------------------------------
Title: Chromospheric flare models.
Authors: Avrett, E. H.; Machado, M. E.; Kurucz, R. L.
1986lasf.conf..216A Altcode:
The calculations presented provide insights on how the observed
chromospheric flare spectrum is produced. The results also suggest
numerous improvements that should be made in the model calculations
in order to interpret observations in better detail. The upper
chromospheric contribution to white light flare emission is due to H,
not H-, but H- plays an important role deeper
in the atmosphere, and there could be a temperature enhancement in
the deeper layers as a result of enhanced radiation produced in the
upper chromosphere. Further work is needed to account for the important
radiative processes, as well as time-dependent and kinetic processes,
that affect the lower atmosphere in solar flares.

---------------------------------------------------------
Title: Theoretical stellar energy distributions.
Authors: Kurucz, R. L.
1986HiA.....7..827K Altcode:
The author's work on model stellar atmospheres is reviewed. In this
context, the shortcomings that still exist in stellar atmosphere
models are stressed, including numerical errors and errors in the
treatment of convection, non-LTE, microturbulent velocity, abundances,
and opacity. Models for A and B stars can be produced that reproduce the
Balmer, Paschen, and Brackett continua and the Balmer line wings. This
implies that even if the physical parameters that characterize the model
for a given star are somewhat off, the temperature-pressure structure
must be correct in the continua and line-wing-forming layers. Improved
models will have a similar structure, but perhaps a somewhat different
effective temperature and gravity.

---------------------------------------------------------
Title: Effective temperature and bolometric correction for HD 61421,
HD 87901, HD 159561, HD 216956.
Authors: Malagnini, M. L.; Morossi, C.; Rossi, L.; Kurucz, R. L.
1985A&A...152..117M Altcode:
The effective temperature and the bolometric correction for four normal
non-supergiant stars are determined from visible spectrophotometry,
IUE data and Kurucz' models. The method applied does not require any
a priori knowledge of the apparent angular diameter of the star. The
excellent agreement of the results with those obtained by using the
apparent angular diameter measured with the stellar interferometer
at Narrabry Observatory demonstrates the soundness of the present
approach. The paper shows how it is possible to overcome the limitation
of direct measurement of angular diameters.

---------------------------------------------------------
Title: Chromosphere flare models
Authors: Avrett, E. H.; Kurucz, R. L.; Machado, M. E.
1985smm..conf.....A Altcode:
Further calculated results based on the F1 and F2 chromospheric models
of Machado et al. (1980) are presented in addition to results from a
model with enhanced temperatures relative to the weak-flare model F1
in the upper photosphere and low chromosphere, and from a model with
enhanced temperatures relative to the strong flare model F2 in the
upper chromosphere. The coupled equations of statistical equilibrium and
radiative transfer for H, H(-), He I-II, C I-IV, Si I-II, Mg I-II, Fe,
Al, O I-II, Na, and Ca II are solved, and the overall absorption and
emission of radiation by lines throughout the spectrum are determined
by means of a reduced set of opacities taken from a compilation of over
10 million lines. Semiempirical models show that the white light flare
continuum may arise by extreme chromospheric overheating, as well as
by an enhancement of the minimum temperature region.

---------------------------------------------------------
Title: Book-Review - Solar Flux Atlas from 296 TO 1300-NM
Authors: Kurucz, R. L.; Furenlid, I.; Brault, J.; Testerman, L.
1985S&T....70...38K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Photospheric Limb Darkening Signatures of Global Structure
Variations
Authors: Petro, L. D.; Foukal, P. V.; Kurucz, R. L.
1985SoPh...98...23P Altcode:
Observations of short-term irradiance variations and consideration
of mechanisms of the solar activity cycle suggest the possibility
of long-term variation of the solar flux. Since the limb darkening
is sensitive to effective temperature and convective efficiency,
observations of the solar limb darkening may provide a useful means
to detect and study long-term global variations. The limb-darkening
responses to impulsive variation (in depth) of the source function,
to effective temperature variation, and to convection variations are
presented. For the variations considered, the limb-darkening variation
is approximately linearly proportional to the associated parameters. The
minimum detectable amplitude of those parametric variations is derived
as a function of observational noise. Given our demonstrated errors
of observation, single-parameter sensitivies are 3 K for effective
temperature variation and 0.007 for local mixing-length variation for
year to year changes at 99% confidence.

---------------------------------------------------------
Title: Investigation of Photospheric Limb-Darkening Variation Between
1980 and 1985
Authors: Petro, L. D.; Foukal, P. V.; Rosen, W. A.; Pierce, A. K.;
Kurucz, R. L.
1985BAAS...17..644P Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Progress on Solar Opacity
Authors: Kurucz, Robert L.
1985BAAS...17..640K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Effective temperature and bolometric correction for HD 61421,
HD 87901, HD 159561, and HD 216956.
Authors: Malagnini, M. L.; Morossi, C.; Rossi, L.; Kurucz, R. L.
1985SSNew...7...16M Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The empirical B.C. (Bolometric Correction) versus
Teff scale for non-supergiant O9 - G5 stars.
Authors: Malagnini, M. L.; Morossi, C.; Rossi, L.; Kurucz, R. L.
1985SSNew...7...17M Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Steps toward a physical calibration of UBV photometry.
Authors: Buser, R.; Kurucz, R. L.
1985IAUS..111..513B Altcode:
The large data base of photoelectric measurements on the Johnson UBV
system has been a primary source of information in many fields of
astrophysical interest. The availability of UBV data for virtually
all types of stars known to make up the stellar populations in
galaxies requires a continued effort toward establishing a fully
physical calibration of these data in order to propagate effectively
the improving knowledge on stellar evolution and stellar atmospheres
(i.e., the HR diagram) through the observations relevant to the
structure and evolution of the galaxies. One of the major links in
this long chain of scientific progress is provided by the synthesis of
stellar photometric properties from theoretical model atmospheres. This
paper will briefly address some of the basic problems involved in the
synthetic color calculations and discuss the theoretical calibration
of UBV photometry as obtained from various grids of model atmospheres
covering a large range of stellar types.

---------------------------------------------------------
Title: A study of solar photospheric limb-darkening variations
Authors: Petro, L. D.; Foukal, P. V.; Rosen, W. A.; Kurucz, R. L.;
Pierce, A. K.
1984ApJ...283..426P Altcode:
The authors have obtained regular observations of photospheric limb
darkening, using the McMath Solar Telescope, to study possible slow
changes in the global temperature structure, in Teff, and in
the ultraviolet continuum flux from the quiet Sun. This paper reports
on the analysis of data obtained on 15 days between 1980 September and
1982 December in a continuum window at λ4451. There are no variations
of global limb darkening exceeding 0.1% at the 99% confidence level. The
implications of these measurements for slow changes in solar luminosity,
convection zone structure, and ultraviolet flux are discussed.

---------------------------------------------------------
Title: New Models of the Solar Temperature Minimum Region and Low
Chromosphere
Authors: Avrett, E. H.; Kurucz, R. L.; Loeser, R.
1984BAAS...16..450A Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Solar flux atlas from 296 to 1300 nm
Authors: Kurucz, Robert L.; Furenlid, Ingemar; Brault, James;
Testerman, Larry
1984sfat.book.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Solar Cycle Temperature Variations in Sunspots
Authors: Maltby, P.; Albregtsen, F.; Moe, O. Kjeldseth; Kurucz, R.;
Avrett, E.
1984LNP...193..176M Altcode: 1984csss....3..176M
The observed umbra/photosphere intensity ratio varies from the beginning
to the end of each solar cycle by ∼ 30% at 1.6 μm and by factors &gt;
2 at visible wavelengths. We present the intensity ratios measured in 10
wavelength bands extending from 0.387 to 2.35 μ m for 22 large sunspots
observed during the period 1968-82, thus covering most of solar cycles
20 and 21. These results together with new observations of umbral limb
darkening, and available data on photospheric absolute intensities,
are used to estimate the dependence of the relative umbral intensity,
and the absolute umbral intensity, on wavelength, heliocentric angle,
and phase of the solar cycle. These umbral intensities are used to
determine preliminary sunspot models which show the temperature as a
function of depth in early, mid-, and late phases of the solar cycle. In
the model calculations we use an extensive new compilation of atomic
and molecular line data, allowing us to carry out the analysis by
means of a detailed synthesis of the observed spectral bands.

---------------------------------------------------------
Title: Variation of Solar Limb Darkening
Authors: Petro, L. D.; Foukal, P. V.; Rosen, W. A.; Kurucz, R. L.;
Pierce, A. K.
1983BAAS...15..951P Altcode:
No abstract at ADS

---------------------------------------------------------
Title: CD - 38 245, A Very Low-Metallicity Giant
Authors: Peterson, R. C.; Carney, B. W.; Kurucz, R. L.
1983BAAS...15..923P Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Synthesis of old systems populations and input metallicities.
Authors: Capuzzo-Dolcetta, R.; Kurucz, R.; Rossi, L.
1983MmSAI..54..829C Altcode:
Problems encountered in generating synthetic spectra for old Population
II stellar systems are discussed. The significance of selecting
stellar atmospheres with appropriate metallicities for stars of
temperatures over 10,000 K is emphasized. Comparisons of metallicity
curves demonstrate that a low metallicity energy distribution is
approximated well by solar composition models, except for a specific
far-UV interval and at a 1550 A wavelength, where metal blends occur.

---------------------------------------------------------
Title: Photospheric and sunspot models from high-resolution spectrum
synthesis.
Authors: Avrett, E. H.; Kurucz, R. L.
1983ITABO..59...43A Altcode:
Kurucz has recently compiled data for a list of 1.7×107
atomic and molecular lines. This list includes most of the lines seen
in the solar spectrum. The authors use the line list and a standard
photospheric model to calculate the detailed photospheric spectrum in
the wavelength band 386 - 388 nm. The calculated spectrum is shown to
be in good agreement with high-resolution observations, duplicating
most individual line features and matching broad-band and maximum
absolute line intensities. The results suggest that the sunspot 386 -
388 nm intensities are formed in the sunspot temperature-minimum region,
and that the observed ≡3350K brightness temperature in this band is
close to the sunspot minimum temperature value.

---------------------------------------------------------
Title: Waht should zero metal red giants look like ?
Authors: Dantona, F.; Kurucz, R.; Mazzitelli, I.; Rossi, L.
1983MmSAI..54..129D Altcode:
Evolutionary modelling of zero metal stars of 0.9-1.0 solar masses
is presented. Attention is focused on the evolution of a 0.8 solar
mass star and a 1.0 solar mass star up to the helium flash, which
will be an order of magnitude less luminous than that expected of
a Population II red giant. It is found that zero metal giant in the
hydrogen shell burning stage are never more luminous than 250 solar
luminosities. The average color of the zero metal giants is calculated
to be B-V = 0.5-0.6, significantly bluer than Population II giants,
and therefore easily discernable at visible wavelengths.

---------------------------------------------------------
Title: A study of convective model stellar atmospheres using a
modified mixing-length theory
Authors: Lester, J. B.; Lane, M. C.; Kurucz, R. L.
1982ApJ...260..272L Altcode:
The ATLAS model atmosphere program is modified to incorporate two
recently proposed changes to the standard mixing-length theory of
convection. These changes are (1) the use of horizontally averaged
opacity in place of the opacity at the average horizontal temperature
and (2) the use of a variable mixing length. The resulting changes in
the structure of the atmosphere are studied by systematically varying
effective temperature, surface gravity, and composition. It is found
that the modified model atmospheres exhibit the following changes:
(1) convection transports a smaller fraction of the total flux;
(2) the convection zone is generally narrower, and the variation of
F(conv)/F(total) with depth is smoother; (3) the temperature is higher
in the convective region; (4) the model is brighter in the spectral
region between 1500 and 2000 A; and (5) there are small, systematic
flux differences in the visual spectral region.

---------------------------------------------------------
Title: Variations in photospheric limb darkening as a diagnostic of
changes in solar luminosity
Authors: Rosen, W. A.; Foukal, P. V.; Kurucz, R. L.; Pierce, A. K.
1982ApJ...253L..89R Altcode:
The paper reports on photospheric limb-darkening measurements
obtained with the McMath Solar Telescope in July, September, and
October 1980 as part of a continuing program to investigate possible
long-term variations in the photospheric emergent flux. A total of
243 usable full-diameter scans were recorded over seven days in the
clean continuum window at 4451-25 A. The limb darkening was found to
decrease significantly between September 25 and 26. It is suggested
that this decrease was caused by a decrease of the temperature gradient
in the upper photosphere in the region above approximately tau(5000) =
0.5. The small increase in effective temperature that might accompany
this limb-darkening variation is estimated using a standard radiative
equilibrium photospheric model.

---------------------------------------------------------
Title: Measurement of the oscillator strengths and autoionization
widths of the neutral-aluminum multiplet 3s2 3p2 P0 - 3s 3p2 2P
Authors: Lombardi, G. G.; Cardon, B. L.; Kurucz, R. L.
1981ApJ...248.1202L Altcode:
The hook method is used in conjunction with absorption equivalent width
measurements to determine the oscillator strengths and line widths of
the Al I multiplet 3s2 3p2 P0 - 3s 3p2 2P at 176 nm. Autoionization is
found to be the dominant decay channel for the two levels of the 3p2
2P term, with autoionizing widths of 4.0 and 0.87 x 10 to the 10th/sec
for J of 3/2 and 1/2, respectively. The van der Waals scattering cross
section for the Al I transition at 176.91 nm by He is determined to
be (1.3 + or - 0.3) x 10 to the -14th sq cm at 2400 K, and a solar
spectrum calculation centered at 176 nm shows that the Al I features
are possible diagnostic probes of (1) solar non-LTE processes, and
(2) the temperature minimum and structure of the lower chromosphere.

---------------------------------------------------------
Title: Solar Spectrum Synthesis. I. A Sample Atlas from 224 to 300 nm
Authors: Kurucz, Robert L.; Avrett, Eugene H.
1981SAOSR.391.....K Altcode:
We have developed sophisticated computer programs for determining
solar and stellar atmospheric structure through the analysis of
spectra. These programs allow us to treat the spectrum as a whole and to
draw much stronger conclusions than would be apparent from individual
spectral features. For a given LTE or non-LTE model atmosphere,
the programs compute the emergent flux or the specific intensity at
up to 20 angles. The spectrum can be broadened by macroturbulence
and rotation; it can be modified by transmission through the Earth's
atmosphere; it can be convolved with the instrumental profile; and it
can finally be plotted together with the observed spectrum with each
line labeled. In the opacity calculation, the lines are broadened by
radiative, Stark, and van der Waals damping, and they can have isotopic
and hyperfine splitting, autoionization, partial redistribution, or be
merged into a continuum. The departure coefficients for ions treated
in non-LTE in the model atmosphere calculation can be used in the
spectrum synthesis programs for all lines of these ions, and highly
ionized lines can be treated in the coronal approximation. The model
atmosphere can have depth-dependent doppler shifts corresponding to
large-scale motions. Using the Vernazza, Avrett, and Loeser models for
the average quiet sun, we have computed theoretical solar spectra that
include all available atomic and molecular line data. In this atlas we
compare with the best available observed spectra in the 224- to 300-nm
wavelength range, namely, the Kohl, Parkinson, and Kurucz (Harvard)
center and limb rocket spectra in the range 224 to 300 nm; the Allen,
McAllister, and Jefferies (Hawaii) disk center rocket spectrum for 268
to 293 nm; and the Brault and Testerman disk center spectrum taken at
Kitt Peak for 294 to 300 nm. We also compare the observed spectra with
each other. The existing spectra are noisy and do not have adequate
resolution, so that it is difficult or impossible to identify weak
features, to resolve blends, to study velocity fields, to search for
variability; or to do any of the projects that can be routinely done
in the visible where high quality spectra are available. Because the
ultraviolet spectrum provides diagnostics for the upper photosphere,
the temperature minimum, and the chromosphere, our understanding of
these regions of the solar atmosphere is seriously impaired. One-half
the lines in the observed spectrum are not identified. The overall
level of the calculation lies considerably above the observed. The
discrepancy is caused mainly by missing atomic and molecular lines and
possibly by errors in the measured continuum opacities. Laboratory
spectral analyses are seriously incomplete, especially for the iron
group atoms and for high J and V molecular levels of CO, SiO, and the
hydrides. Any model atmosphere or non-LTE rate calculation that depends
directly on available ultraviolet opacities should not be trusted.

---------------------------------------------------------
Title: An Improved Theoretical Solar Photospheric Model
Authors: Kurucz, R. L.
1981BAAS...13..888K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Photospheric Limb Darkening as a Ground-based Diagnostic for
Variations in the Solar Effective Temperature
Authors: Rosen, W. A.; Foukal, P. V.; Kurucz, R.; Pierce, A. K.
1981BAAS...13..551R Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Semiempirical Calculation of gf Values, IV: Fe II
Authors: Kurucz, Robert L.
1981SAOSR.390.....K Altcode:
Slater parameters, eigenvalues, eigenvectors, and scaled
Thomas-Fermi-Dirac wavefunctions have been computed for all known
configurations of Fe II. The complete transition array has been
computed, together with partial sums required for radiative,
Stark, and van der Waals damping constants. A listing of the 431,
933 strongest lines is available on magnetic tape. A subset of that
listing containing 22, 547 lines between observed energy levels is
presented here. Comparisons are made with other published lifetime
and gf value data.

---------------------------------------------------------
Title: A table of semiempirical gf values. Pt 4: FeII
Authors: Kurucz, R. L.
1981tsgv.book.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Solar Spectrum Synthesis I. A sample atlas from 224 to 300 NM
Authors: Kurucz, Robert L.; Avrett, Eugene H.
1981ssss.book.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Model Atmospheres for Globular Cluster Stars
Authors: Kurucz, R. L.
1981apgc.conf..289K Altcode: 1981IAUCo..68..289K; 1981LDP.....2..289K
No abstract at ADS

---------------------------------------------------------
Title: Semiemprical calculation of gf values
Authors: Kurucz, Robert L.
1980AIPC...63..163K Altcode: 1980susp.conf..163K
Because of the large scatter in my gf values in comparison to laboratory
values which was well demonstrated by Wiese in his presentation, I am
going to spend most of my time explaining the reasons for the scatter
so that you will not worry unduly about using my calculations. Then
I will mention my spectrum synthesis programs in passing and finally
I will talk about future calculations that will provide oscillator
strength data for Ni, Co, and Fe in supernova spectra.

---------------------------------------------------------
Title: Si0 in the Ultraviolet Solar Spectrum
Authors: Kurucz, R. L.
1979BAAS...11Q.710K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Sample Spectral Atlas for Sirius
Authors: Kurucz, Robert L.; Furenlid, Ingemar
1979SAOSR.387.....K Altcode:
We present a sample spectral atlas of Sirius for the region 354 to
440 nm in which we show a photographic spectrum that resolves the
line profiles and has a small-scale signal to noise better than
300. The atlas also shows a calculated spectrum that demonstrates
our capabilities in spectrum synthesis. We are able to compute a
spectrum, broaden it with microturbulence and rotation, transmit it
through the atmosphere, convolve it with the instrumental profile,
plot it together with the observed spectrum, and label each line. This
approach to analyzing stellar spectra has a number of advantages over
working with lists of line identifications or equivalent widths or
individual line profiles: (1) The reader gets an immediate impression
of the quality of the data and of blending, and many lines that
appear to be single are shown to be blends. (2) The reader can
much better estimate the continuum level and the total blocking
to check model atmosphere predictions and assess the reliability
of an abundance determined from any given line. (3) Determinations
of stellar parameters and abundances can be based on all the data,
not just on a small sample. (4) The reader gets an intuitive "feel"
for the data and for the properties of the star, which is missing in
other approaches. (5) All the data are presented and the reader who
disagrees with our treatment can reanalyze them. Our programs can be
used to analyze existing and future ground-based, balloon, rocket,
and satellite observations of the sun and stars. For Sirius we plot
a roughly photometric spectrum at 10 nm/panel, then at 5 nm/panel
with a comparison rotationally broadened calculated spectrum, then at
0.8 nm/panel with comparison unbroadened and rotationally broadened
calculated spectra and line identifications. No attempt has yet been
made to fit the calculated spectra to the observed spectrum. The
observed spectrum has been only roughly normalized to the calculated
spectrum to make it photometric. From the sample spectrum it is clear
that Sirius is strongly underabundant in Ca, contrary to earlier
studies, and that its abundances are roughly consistant with other
metallic line stars although not extreme. There is no region of the
spectrum shown here that is not produced by overlapping lines.

---------------------------------------------------------
Title: Model atmospheres for G, F, A, B, and O stars.
Authors: Kurucz, R. L.
1979ApJS...40....1K Altcode:
A grid of LTE model atmospheres is presented for effective temperatures
ranging from 5500 to 50,000 K, gravities from the main sequence down
to the radiation-pressure limit, and abundances solar, 1/10 solar,
and 1/100 solar. The models were computed by use of a statistical
distribution-function representation of the opacity of almost a
million atomic lines. For each model the temperature structure,
fluxes, UBV and uvby colors, bolometric correction, and Balmer line
profiles are tabulated. The solar-abundance models are compared with
narrow-, intermediate-, and wide-band photometry and found to be in
good agreement with the observations for effective temperatures above
8000 K. Excellent agreement exists with the spectrophotometry and Balmer
line profiles of Vega. A small systematic error in the colors of late A
and F stars is probably due to an overstimate of convection in weakly
convective models. This error does not seem to affect greatly the use
of the predicted colors for differential studies. The solar model has
approximately a 2% error in the V flux because molecular lines were
not included.

---------------------------------------------------------
Title: High resolution atmospheric transmission calculations down
to 28.7 km in the 200-243-nm spectral range (TE)
Authors: Cann, M. W. P.; Evans, W. F. J.; Kohl, J. L.; Kurucz, R.;
Parkinson, W. H.; Reeves, E. M.; Nicholls, Ralph W.
1979ApOpt..18..964C Altcode:
Decrease in stratospheric ozone absorption and increase in oxygen
absorption with decreasing wavelength combine to produce a window
of maximum atmospheric transmission near 210 nm. Since solar
radiation in this spectral region dissociates molecular oxygen,
the deep atmospheric penetration at this wavelength is of particular
aeronomical interest. High resolution calculations of the transmittance
down to 28.65 km were made for the 200-243-nm spectral range in this
window region, in support of a stratospheric balloon flight from Fort
Churchill in July 1974. The calculations were made by dividing the
atmosphere into layers which were chosen so that each could be assumed
homogeneous; optical depths were calculated separately for each of
these layers and then summed to obtain the over-all transmittance of the
atmosphere. Absorption by molecular oxygen (line and continuum) and by
ozone was included, as well as extinction through Rayleigh scattering
by air molecules. The calculated transmittances were combined with high
altitude (above 100-km) rocket measurements of the sun-center spectrum
and center-to-limb variations to give residual high resolution solar
spectral flux for several altitudes and solar zenith angles.

---------------------------------------------------------
Title: Theoretical Colors for Helium Rich Cepheids.
Authors: Whitaker, R. W.; Kurucz, R. L.
1979BAAS...11..438W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A progress report on theoretical photometry.
Authors: Kurucz, R. L.
1979DudOR..14..363K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A systematic investigation of multicolor photometric
system. III. Theoretical UBV colors and the temperature scale for
early-type stars.
Authors: Buser, R.; Kurucz, R. L.
1978A&A....70..555B Altcode:
Summary. We present synthetic UBV colors for early- type stars computed
from a new grid of blanketed model atmospheres by Kurucz (1978), and
from the revised response functions by Buser (1978). Excellent agreement
with Johnson's (1966) mean `intrinsic' U-B and B - V colors for main
sequence stars is obtained. The theoretical effective temperature
scale and the bolometric corrections agree well with the empirical
results found by Code et al. (1976). Key words: stars: early-type -
blanketed model atmospheres - effective temperature scale - bolometric
corrections - synthetic UBV colors.

---------------------------------------------------------
Title: Solar Spectrum Synthesis
Authors: Kurucz, R. L.
1978BAAS...10..658K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A theoretical analysis of uvby photometry.
Authors: Relyea, L. J.; Kurucz, R. L.
1978ApJS...37...45R Altcode:
Theoretical Stromgren uvby and Johnson-Morgan UBV colors have been
calculated from the Kurucz (1978) grid of model atmospheres for G, F,
A, B, and O stars, and calibrated to the standard systems using a model
atmosphere for Vega with an effective temperature of 9400 K and log g =
3.95. The resultant color-color grids are analyzed, and the usefulness
of the photometric systems for derivation of atmospheric effective
temperature, surface gravity, and abundance is assessed. For the uvby
system, excellent agreement between the models and observations is
obtained for effective temperatures of at least 8500 K, and photometric
grids for use in reducing observations are presented. A discrepancy is
found for effective temperatures below 8500 K, and possible sources
of error are discussed. For the UBV system, because of nonlinear
transformations, no accurate system calibration is presented.

---------------------------------------------------------
Title: Center and limb solar spectrum in high spectral resolution
225.2 NM to 319.6 NM
Authors: Kohl, John L.; Parkinson, William H.; Kurucz, Robert L.
1978clss.book.....K Altcode: 1978QB551.K63......
The atlas has been designed to fulfill the need in solar and stellar
astronomy, in aeronomy, and in space science for a convenient reference
source that provides a detailed and accurate record of the measured
solar ultraviolet spectrum in high spectral resolution for the
wavelength range from 225.2 nm to 319.6 nm. The atlas also contains
a preliminary synthetic solar spectrum with a legend for identifying
and describing the features of the synthetic spectrum. Attention is
given to aspects of instrumentation, the radiometric calibration,
the wavelength scale, background noise random fluctuations and
data filtering, intermittent noise, the observational conditions,
the experimental uncertainty, the atlas format, references, tables,
and plots.

---------------------------------------------------------
Title: Theoretical stellar chromospheres of late type
stars. II. Temperature minima.
Authors: Ulmschneider, P.; Schmitz, F.; Renzini, A.; Cacciari, C.;
Kalkofen, W.; Kurucz, R.
1977A&A....61..515U Altcode:
The theory of heating by short period acoustic waves is applied to
predict the height of shock formation and the acoustic flux at the
base of the chromosphere for stars with effective temperatures of
4000 to 6500 K and log g of 2 to 4. These predictions are compared
with heights of temperature minima and with chromospheric radiation
losses computed from semiempirical models.

---------------------------------------------------------
Title: The rotational velocity and barium abundance of Sirius.
Authors: Kurucz, R. L.; Traub, W. A.; Carleton, N. P.; Lester, J. B.
1977ApJ...217..771K Altcode:
We have measured the Ba ii 649.69 nm line profile in Sirius using a
PEPSIOS interferometer. We find a projected rotational velocity V sin
i of 16 + 1 km 1; a heliocentric radial velocity of -8.6 + 0.4km 1;
and a log Ba abundance of -8.18 + 0.15 relative to all atoms by number
(3.87 if log H = 12), which is greater than the solar abundance by
1.76 + 0.18. Subject headings: stars: abundances stars: individual -
stars: rotation

---------------------------------------------------------
Title: The ultraviolet spectra of Alpha Aquilae and Alpha Canis
Minoris.
Authors: Morton, D. C.; Spinrad, H.; Bruzual A., G.; Kurucz, R. L.
1977ApJ...212..438M Altcode:
Scans of Alpha Aql (A7 IV, V) and Alpha CMi (F5 IV-V) obtained with
the Copernicus satellite spectrometer over the wavelength range from
2100 to 3200 A are presented along with a spectrum of the integrated
solar disk over the same range procured during a calibrated rocket
flight. About 1500 fairly strong absorption lines in the Alpha CMi
spectrum between 2400 and 2961 A are identified by comparison with
a solar atlas and by using a theoretical spectrum synthesized from
a blanketed LTE model with an effective temperature of 6500 K and a
surface gravity of 10,000 cm/sec per sec. The Mg II resonance doublet
at 2795.528 and 2802.704 A is found to be present in all three stars
together with a discontinuity at 2635 A due to Fe II, Fe I, Cr I, and
Mn II. It is concluded that the Mg II resonance lines and the 2635-A
continuum break would be the best spectral features for estimating the
redshift of a galaxy observed at low resolution provided the redshift
is not less than about 0.75.

---------------------------------------------------------
Title: The Fourth Positive System of Carbon Monoxide
Authors: Kurucz, Robert L.
1976SAOSR.374.....K Altcode:
For the Fourth Positive system of CO we present tables of energy levels,
Frank-Condon factors, r-centroids, transition moments, line wavelengths,
and gf values.

---------------------------------------------------------
Title: Stellar model chromospheres. V. Alpha Centauri A (G2 V)
and Alpha Centauri B (K1 V).
Authors: Ayres, T. R.; Linsky, J. L.; Rodgers, A. W.; Kurucz, R. L.
1976ApJ...210..199A Altcode:
Models for the upper photospheres and lower chromospheres of Alpha
Centauri A and B are derived from high-dispersion spectrograms of the
Ca II K-line emission cores and damping wings. Effective temperatures,
surface gravities, and ages consistent with the measured broadband
colors, metallicities, and absolute magnitudes are estimated for the
two stars. The spectrograms are calibrated by fitting the far-wing K
profiles with synthetic fluxes based on radiative-equilibrium models,
and the model atmospheres are obtained through a partial-redistribution
analysis of the line cores and damping wings. These models are compared
with those previously proposed for Procyon, Arcturus, and the sun. Many
features in all the models are found to be quite similar, and some
evidence suggests that Alpha Cen A may be significantly older and
more evolved than the sun, even though both stars exhibit similar
chromospheric properties.

---------------------------------------------------------
Title: Solar Ultraviolet Spectrum Synthesis.
Authors: Kurucz, R. L.
1976BAAS....8..502K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Possible Role of Radiative Acceleration in Supporting
Extended Atmospheres in be Stars
Authors: Kurucz, R. L.; Schild, R. E.
1976IAUS...70..377K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Line Blanketing in VEGA and Sirus
Authors: Kurucz, R. L.
1976sao..rept.....K Altcode:
A theoretical model and spectrum calculation for Vega is discussed. The
abundance of carbon is approximately -3.8, which is 0.3 lower than
the old solar value and supports Mount and Linsky's newer value. The
oxygen abundance is approximately -3.5. Assuming that Vega has
solar abundances, the solar oxygen abundance appears to have been
overestimated by 0.3 in the log. Other abundances appear to be
solar. For Sirius the calculations do not agree with the observed
spectrum. Line opacity is considerably underestimated, notably in
third-spectrum iron group lines. Carbon is underabundant relative
to Vega by 0.2 in the log. Nitrogen is unchanged. Oxygen is enhanced
by 0.3. Heavier elements are enhanced by 1.0 in the log. Calibration
yields 1.3E-10 ergs/sq cm/s/nm for each U1 Copernicus count at 130 nm.

---------------------------------------------------------
Title: a Progress Report on Theoretical Four-Dimensional Photometry
of F a, and B Stars
Authors: Kurucz, Robert L.
1975mpth.conf..271K Altcode: 1975mpth.proc..271K
No abstract at ADS

---------------------------------------------------------
Title: A table of semiempirical gf values. Pt 1: Wavelengths: 5.2682
NM to 272.3380 nm; Pt 2: Wavelengths: 272.3395 NM to 599.3892 nm;
Pt 3: Wavelengths: 599.4004 NM to 9997.2746 NM
Authors: Kurucz, R. L.; Peytremann, E.
1975SAOSR.362.....K Altcode: 1975tsgv.book.....K; 1975SAOSR.362....3K; 1975SAOSR.362....0K
We tabulate gf values for 265,587 atomic lines selected from the
line data used by Kurucz, Peytremann, and Avrett (1974) to calculate
line-blanketed model atmospheres. These data are especially useful
for line identification and spectral synthesis in solar and stellar
spectra. Except for 10,000 lines taken from the literature, the
gf values have been calculated semiempirically by using scaled
Thomas-Fermi-Dirac radial wavefunctions and eigenvectors found
through least-squares fits to observed energy levels. Included in
the calculation were the first five or six stages of ionization for
sequences up through nickel. Published gf values have been included
for elements heavier than nickel. The tabulation is restricted to
lines with wavelengths less than 10 μm.

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Title: Semiempirical Calculation of gf Values, Iii: Interstellar
Lines of the Iron Group
Authors: Kurucz, R. L.
1974SAOSR.360.....K Altcode:
Iron-group gf values are tabulated for lines that might appear in the
interstellar medium.

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Title: Semiempirical Calculation of gf values, II: Fe
I(3d+4s)8 - (3d+4s)7 4p
Authors: Kurucz, Robert L.
1974SAOSR.359.....K Altcode:
No abstract at ADS

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Title: Semiempirical calculation of gf values, II: Fe I
(3d+4s)8-(3d+4s)74p.
Authors: Kurucz, R. L.
1974SAOSR.359....9K Altcode:
No abstract at ADS

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Title: Stellar Spectral Synthesis in the Ultraviolet
Authors: Kurucz, Robert L.
1974ApJ...188L..21K Altcode:
A computer program for spectral synthesis has been developed, based
on a list of data for atomic lines described by Kurucz, Peytremann,
and Avrett. To demonstrate the usefulness of this program, we present
a sample calculation of the region around the C w resonance doublet
at 155 nm, which is a feature in rocket and satellite spectra of B
stars. The calculation indicates that the observed feature is a blend
of many lines in addition to C iv, so that detailed calculations
are necessary for the correct interpretation of the observational
data. Subject headings: atmospheres, stellar-line profiles-ultraviolet

---------------------------------------------------------
Title: Report on the Celescope ultraviolet observations from the OAO
2 satellite and associated research at the Smithsonian Astrophysical
Observatory.
Authors: Avrett, E.; Davis, R.; Deutschman, W.; Haramundanis, K.;
Kurucz, R.; Payne-Gaposchkin, C.; Peytremann, E.; Schild, R.
1974spre.conf..515A Altcode:
No abstract at ADS

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Title: Blanketed model atmospheres for early-type stars
Authors: Kurucz, Robert L.; Peytremann, Eric; Avrett, Eugene H.
1974bmae.book.....K Altcode: 1974QB843.E2K37....
No abstract at ADS

---------------------------------------------------------
Title: Report on the Celescope ultraviolet observations from the OAO-2
satellite and associated research at the Smithsonian Astrophysical
Observatory.
Authors: Avrett, E.; Davis, R.; Deutschman, W.; Haramundanis, K.;
Kurucz, R.; Payne-Gaposchkin, C.; Peytremann, E.; Schild, R.
1974rnuo.confC...2A Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A Preliminary Theoretical Line-Blanketed Model Solar
Photosphere
Authors: Kurucz, Robert L.
1974SoPh...34...17K Altcode:
A preliminary theoretical solar model is presented that produces closer
agreement with observation than has been heretofore possible. The
qualitative advantages and shortcomings of this model are discussed
and projected improvements are outlined.

---------------------------------------------------------
Title: Semiempirical Calculation of gf Values: sc II
(3d+4s)2 - (3d+4s) 4p, a Detialed Example
Authors: Kurucz, R. L.
1973SAOSR.351.....K Altcode:
A semiempirical procedure for calculating gf values is developed
in detail. A program written by R. D. Cowan is used to produce LS
transition arrays and electrostatic and spin-orbit matrices. Transition
integrals are evaluated with scaled Thomas- Fermi-Dirac wavefuntions
following Warner. Eigenvectors are found through a least-squares
procedure that fits computed eigenvalues to observed energy levels,
and then the eigenvectors are used to transform the LS transition
array to the observed coupling scheme. Throughout the discussion,
examples are given for Sc II (3d+4s)2 - (3d+4s) 4p. The
final computed gf values are compared to laboratory measurements.

---------------------------------------------------------
Title: Line-Blanketed Model Atmospheres.
Authors: Kurucz, Robert Louis
1973PhDT.........4K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Atlas: a Computer Program for Calculating Model Stellar
Atmospheres
Authors: Kurucz, R. L.
1970SAOSR.309.....K Altcode:
The computer program ATLAS calculates model stellar atmospheres
in radiative and convective equilibrium for the complete range of
stellar temperatures. The apporximations used limit the program to
plane-parallel, horizontally homogeneous, stedy-state, nonmoving
atmospheres with energy and abundances constant with depth. The
program has been written to allow detailed statistical equillibrium
calculations, but only hydrogen continua and H- are
coded at present. Most of the published continuous opacities and
hydrogen lines have been included, and provision is made for adding
others easily. There is also provision for treating line opacity as
line absorption distribution functions. In Sections 2 through 7, we
discuss all aspects of model atmosphere calculations in considerable
detail. These include the radiation field, statistical equilibrium,
thermodynamic properties, opacity, convection, and the temperature
correction. In Sections 8 and 9, we discuss the computer program
itself, by going first through a sample calculation and second through
a technical discussion of the program coding and operation. The program
was written in FORTRAN IV and is essentially machine independent. A
listing is available on magnetic tape.

---------------------------------------------------------
Title: Atlas: A computer program for calculating model stellar
atmospheres
Authors: Kurucz, R. L.
1970acpc.book.....K Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A Matrix Method for Calculating the Source Function, Mean
Intensity, and Flux in a Model Atmosphere
Authors: Kurucz, Robert L.
1969ApJ...156..235K Altcode:
The integrals for the mean intensity and flux are expressed as the
multiplication of the source-function vector by matrix representations
of the integral operators. This method leads to a rapid solution of
the integral equation for the source function and to an efficient
calculation of the mean intensity and flux

---------------------------------------------------------
Title: The Grid of Model Stellar Atmospheres from 50,000° to 11,000°
Authors: Kurucz, R.
1969tons.conf..375K Altcode:
No abstract at ADS

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Title: The Rocket Ultraviolet Spectra of a Stars
Authors: Maran, Stephen P.; Kurucz, Robert L.; Strom, K. M.; Strom,
Stephen E.
1968ApJ...153..147M Altcode:
A synthetic spectrum covering the wavelength range 2000-3000 A has
been computed for a tempera- ture and surface gravity appropriate to
a main-sequence early A star. The strongest lines and also those of
potential value in discussing nucleosynthesis problems are tabulated

---------------------------------------------------------
Title: Effects of Line Blanketing on the Solar Windows
Authors: Carbon, Duane; Gingerich, Owen; Kurucz, Robert
1968SoPh....3...55C Altcode:
The increasingly high flux predicted to the violet of 4500 Å
by many model solar atmospheres stands in contradiction to the
observations. Since one possible cause of the disagreement is that
the solar `windows' by which the observed continuum is established
might be obscured by line wings, we have made detailed calculations
of these narrow spectral regions. With the exception of a few windows
affected by the wings of Balmer lines, those redward of the Balmer
discontinuity appear free of line blanketing. Even the assumption that
the ultraviolet continuum is depressed 5% by unseen lines not included
in our calculations leaves substantial disagreements between the models
and observations. The discrepancies could perhaps be explained by a
veil of weak lines across the ultraviolet spectrum.

---------------------------------------------------------
Title: Statistical Procedure for Computing Line-Blanketed Model
Stellar Atmospheres.
Authors: Strom, S. E.; Kurucz, R.
1966AJ.....71S.181S Altcode:
In order to treat the problem of line blanketing in computing
model stellar atmospheres we have developed a modified picket-fence
approach. We divide the frequency range between the Lyman limit and 44
000 A into 16 separate regions and for each of these regions we compute
at 34 optical depths a function N (H). This function descril~es the
number distribution of the ratio of line to continuum opacity H. It is
computed using a compilation of transition probabilities and excitation
potentials for 28 500' spectral lines. The function N(H) is used to
choose five values of H for each frequency region. Corresponding to
each H is the fraction W of the particular frequency region occupied by
opacity ratios equal to or less than H. The values of H and W for each
frequency region and the continuum opacities are then used as input
to a modified version of the stellar atmosphere program discussed by
Strom and Avrett (Astrophys. J. Siippl. 12,1, 1965). We have tested
the numerical accuracy of our program by comparing with the results
obtained by Avrett for a grey atmosphere and a simple picket- fence
absorption coefficient. Finally, we discuss the use of this program
for the analysis of Procyon.