Issue |
A&A
Volume 392, Number 2, September III 2002
|
|
---|---|---|
Page(s) | 619 - 636 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20020788 | |
Published online | 30 August 2002 |
New grids of ATLAS9 atmospheres I: Influence of convection treatments on model structure and on observable quantities
1
Institut für Astronomie, Universität Wien, Türkenschanzstrasse 17, 1180 Vienna, Austria e-mail: heiter@astro.univie.ac.at; kupka@astro.univie.ac.at; weiss@astro.univie.ac.at; schmidt@astro.univie.ac.at
2
Department of Astronomy, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-7215, USA e-mail: ulrike@fafnir.astr.cwru.edu
3
Observatoire de Paris-Meudon, 5 place Jules Janssen, 92195 Meudon Cedex, France e-mail: Claude.VantVeer@obspm.fr; Caroline.Barban@obspm.fr; MarieJo.Goupil@obspm.fr; David.Katz@obspm.fr
4
National Solar Observatory, 950 N. Cherry Ave., Tucson, AZ 85719, USA e-mail: barban@noao.edu
5
Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching, Germany e-mail: wschmidt@mpa-garching.mpg.de
6
Instituto de Astrofisica de Andalucia, C.S.I.C., Apdo. 3004, 18080 Granada, Spain e-mail: garrido@iaa.es
Corresponding author: U. Heiter, heiter@astro.univie.ac.at
Received:
5
February
2002
Accepted:
13
May
2002
We present several new sets of grids of model stellar atmospheres
computed with modified versions of the ATLAS9 code. Each individual set
consists of several grids of models with different metallicities ranging
from [M/H] 2.0 to +1.0 dex. The grids range from 4000
to 10 000 K in Teff and from 2.0 to 5.0 dex in
.
The individual sets differ from each other and from previous ones
essentially in the physics used for the treatment of the
convective energy transport, in the higher vertical resolution
of the atmospheres and in a finer grid in the (Teff,
) plane.
These improvements enable the
computation of derivatives of color indices accurate enough for
pulsation mode identification. In addition, we show that the chosen vertical
resolution is necessary and sufficient for the purpose of stellar
interior modelling. To explain the physical differences
between the model grids we provide a description of the currently
available modifications of ATLAS9 according to their treatment
of convection. Our critical analysis of the dependence
of the atmospheric structure and observable quantities on convection treatment,
vertical resolution and metallicity reveals that spectroscopic and photometric
observations are best represented when using an inefficient
convection treatment. This conclusion holds whatever convection
formulation investigated here is used, i.e. MLT(
), CM and CGM are
equivalent. We also find that changing the convection
treatment can lead to a change in the effective temperature estimated from
Strömgren color indices from 200 to 400 K.
Key words: stars: atmospheres / stars: fundamental parameters / stars: variables δ Scuti stars / convection
© ESO, 2002
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