TiO and H2O Absorption Lines in Cool Stellar Atmospheres

By F. Allard, Peter Hauschildt, D. Schwenke. 2000

158 citations recorded by the source corpus.

We compare the structures of model atmospheres and synthetic spectra calculated using different line lists for TiO and water vapor. We discuss the effects of different line list combinations on the model structures and spectra for both dwarf and giant stars. It is shown that recent improvements result in significantly improved spectra, in particular, in the optical where TiO bands are important. The water vapor-dominated near-infrared region remains problematic as the current water line lists do not yet completely reproduce the shapes of the observed spectra. We find that the AMES TiO list provides more opacity in most bands and that the new, smaller oscillator strengths lead to systematically cooler temperatures for early-type M dwarfs than previous models. These effects combine and will help to significantly improve the fits of models to observations in the optical as well as result in improved synthetic photometry of M stars. We show that the Davis, Littleton, & Phillips fel-values for the δ and φ bands of TiO best reproduce the observed V-I color indices.

Subfields: Astronomy and Astrophysics, Atmospheric Science, Spectroscopy

View Paper: https://www.semanticscholar.org/paper/56ef75f037fec5531db2f050c5a5415a2bf84c15

How researchers see this paper

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In Astronomy and Astrophysics

1. C. Knigge
2. F. Allard
3. Peter Hauschildt
4. K. Luhman
5. A. Schweitzer
6. P. Roche
7. P. Lucas
8. M. Marley

In Atmospheric Science

1. C. Knigge
2. F. Allard
3. Peter Hauschildt
4. A. Schweitzer
5. P. Lucas
6. P. Roche
7. J. D. Kirkpatrick
8. K. Luhman

In Spectroscopy

1. C. Knigge
2. F. Allard
3. Peter Hauschildt
4. P. Roche
5. P. Lucas
6. A. Schweitzer
7. M. Marley
8. J. D. Kirkpatrick

Citations in the corpus

• Infrared Spectroscopy of Substellar Objects in Orion (2001, methodology): “The AMES-Dusty-1999 spectra appear to represent a significant improvement over previous models (such as NextGen) of cool dwarfs at infrared wavelengths, as discussed by Allard, Hauschildt & Schwenke (2000b, hereafter AHS).”
• The Limiting Effects of Dust in Brown Dwarf Model Atmospheres (2001, methodology): “This offset of the current models to the blue of the earlier NextGen models is due to some inaccuracies of the NASA-Ames H2O opacity database in describing these relatively hot atmospheres (see Allard, Hauschildt and Schwenke 2000 for details).”
• The Donor Stars of Cataclysmic Variables (2006, background): “The second, which we call AMES-MT, is an updated version of the BCAH98 models and has been suggested to provide a somewhat better match to observed optical colours (Allard, Hauschildt & Schwenke 2000).”