Atmospheric parameters of the variable DB white dwarf GD 358.
Koester, D.; Weidemann, V.; Vauclair, G.; Oke, J. B.; Greenstein, J. L.; Dolez, N.
Germany, France, United States
Abstract
This paper presents new observations of GD 358, the prototype of the class of variable white dwarfs with helium-dominated atmospheres (DB). These data, together with previous observations, are analyzed using new model atmosphere calculations. The results are Teff = 24000±1000K, log g = 8.0±0.3. This temperature is within the range predicted for instability strips. It seems to demand more effective convection than provided by the standard mixing length approximation. The implications of this result for the understanding of convection and white dwarf pulsations are discussed.