SIMBAD references

1997A&A...328..349S - Astronomy and Astrophysics, volume 328, 349-360 (1997/12-1)

The role of convection on the uvby colours of A, F, and G stars.


Abstract (from CDS):

We discuss the effects of convection on the theoretical uvby colours of A, F, and G stars. The standard mixing-length theory atlas9 models of Kurucz (1993, CD-ROM 13: ATLAS9, SAO, Cambridge, USA), with and without approximate overshooting, are compared to models using the turbulent convection theory proposed by Canuto & Mazzitelli (1991ApJ...370..295C, 1992ApJ...389..724C) and implemented by Kupka (1996, ASPConf. Proc. 108, 73). Comparison with fundamental Teff and logg stars reveals that the Canuto & Mazzitelli models give results that are generally superior to standard mixing-length theory (MLT) without convective overshooting. MLT models with overshooting are found to be clearly discrepant. This is supported by comparisons of non-fundamental stars, with Teff obtained from the Infrared Flux Method and logg from stellar evolutionary models for open cluster stars. The Canuto & Mazzitelli theory gives values of (b-y)0 and c0 that are in best overall agreement with observations. Investigations of the m0 index reveal that all of the treatments of convection presented here give values that are significantly discrepant for models with Teff<6000K. It is unclear as to whether this is due to problems with the treatment of convection, missing opacity, or some other reason. None of the models give totally satisfactory m0 indices for hotter stars, but the Canuto & Mazzitelli models are in closest overall agreement above 7000K. Grids of uvby colours, based on the CM treatment of convection, are presented. These grids represent an improvement over the colours obtained from models using the mixing-length theory. The agreement with fundamental stars enables the colours to be used directly without the need for semi-empirical adjustments that were necessary with the earlier colour grids.

Abstract Copyright:

Journal keyword(s): convection - stars: atmospheres - stars: general - stars: fundamental parameters

VizieR on-line data: <Available at CDS (J/A+A/328/349): cm_m05.dat cm_m10.dat cm_p00.dat cm_p05.dat cm_p10.dat table5>

Simbad objects: 130

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