New theories of convection in the context of a recent analysis of the DBV white dwarf GD 358

Abstract

We present updated evolutionary calculations for carbon-oxygen DB white dwarfs using the self-consistent model for turbulent convection recently developed by Canuto, Goldman & Mazzitelli (CGM). To this end, we employ a detailed stellar evolutionary code in which we include a new equation of state for helium plasmas computed by Saumon, Chabrier & Van Horn as well as new OPAL radiative opacities. The present study is aimed at assessing the compatibility of the CGM model with the recent effective temperature redetermination of the pulsating DB white dwarf star GD 358. This star defines the blue edge of the DB white dwarf instability strip. Using thermal time-scale arguments, we find that the DB blue edges given by the CGM fit to the effective temperature of GD 358 are much better than those given by the previous Canuto & Mazzitelli model.