New grids of ATLAS9 atmospheres I: Influence of convection treatments on model structure and on observable quantities

Ulrike Heiter, Friedrich Kupka, C van 'T Veer-Menneret, Caroline Barban, Werner Wolfgang Weiss, Marie J. Goupil, W. Schmidt, David Katz, Rafael Garrido (Korresp. Autor*in)

Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed


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 log g. 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, log g) 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(a = 0.5), CM and CGM are equivalent. We also find that changing the convection treatment can lead to a change in the effective temperature estimated from Strošmgren color indices from 200 to 400 K.
Seiten (von - bis)619-636
FachzeitschriftAstronomy & Astrophysics
PublikationsstatusVeröffentlicht - 2005

ÖFOS 2012

  • 103003 Astronomie