A New Stellar Atmosphere Grid and Comparisons with HST/STIS CALSPEC Flux Distributions

The Space Telescope Imaging Spectrograph has measured the spectral energy distributions for several stars of types O, B, A, F, and G. These absolute fluxes from the CALSPEC database are fit with a new spectral grid computed from the ATLAS-APOGEE ATLAS9 model atmosphere database using a chi-square mi...

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Bibliographic Details
Published inThe Astronomical journal Vol. 153; no. 5; pp. 234 - 244
Main Authors Bohlin, Ralph C., Mészáros, Szabolcs, Fleming, Scott W., Gordon, Karl D., Koekemoer, Anton M., Kovács, József
Format Journal Article
LanguageEnglish
Published United States The American Astronomical Society 01.05.2017
Subjects
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
COMPARATIVE EVALUATIONS
ENERGY SPECTRA
INTERFEROMETRY
SPACE
STAR MODELS
STARS
stars: atmospheres
stars: fundamental parameters
STELLAR ATMOSPHERES
techniques: spectroscopic
TELESCOPES
WAVELENGTHS
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Summary:The Space Telescope Imaging Spectrograph has measured the spectral energy distributions for several stars of types O, B, A, F, and G. These absolute fluxes from the CALSPEC database are fit with a new spectral grid computed from the ATLAS-APOGEE ATLAS9 model atmosphere database using a chi-square minimization technique in four parameters. The quality of the fits are compared for complete LTE grids by Castelli & Kurucz (CK04) and our new comprehensive LTE grid (BOSZ). For the cooler stars, the fits with the MARCS LTE grid are also evaluated, while the hottest stars are also fit with the NLTE Lanz & Hubeny OB star grids. Unfortunately, these NLTE models do not transition smoothly in the infrared to agree with our new BOSZ LTE grid at the NLTE lower limit of Teff = 15,000 K. The new BOSZ grid is available via the Space Telescope Institute MAST archive and has a much finer sampled IR wavelength scale than CK04, which will facilitate the modeling of stars observed by the James Webb Space Telescope. Our result for the angular diameter of Sirius agrees with the ground-based interferometric value.
Bibliography:AAS04594
Stars and Stellar Physics
ISSN:0004-6256
1538-3881
1538-3881
DOI:10.3847/1538-3881/aa6ba9