AAS 207th Meeting, 8-12 January 2006
Session 205 White Dwarfs
Oral, Thursday, 2:00-3:30pm, January 12, 2006, Salon 1

## [205.04] Constraining Convection in White Dwarfs Using Non-sinusoidal Pulse Shapes

M. H. Montgomery, D. E. Winget (University of Texas)

The physics of convection represents one of the largest sources of uncertainty in modeling stars. In main sequence objects, convection is believed to occur in the cores of stars more massive than the Sun and in the envelopes of stars having masses less than about 2.0 M\odot, while Red Giants and other stars cooler than the Sun should have fully convective envelopes.

We have recently shown that the non-sinusoidal light curves of two pulsating white dwarfs can be explained by accounting for the change in depth of the convection zone in response to the pulsations. This allows us to place constraints on the physics of convection in these objects and, for instance, to test whether the commonly used mixing-length theories can provide a reasonable description of this physics. Finally, we describe a program for observing pulsating white dwarfs across their instability strips which will allow us to map out directly the depth of their convection zones as a function of T\rm eff and \log g. The results of this work will provide powerful boundary conditions'' on both analytical and hydrodynamical models of convection to be tried and used on objects throughout the H-R diagram.

This work is supported in part by National Science Foundation grant AST-0507639.