We determine the structure of the pulsating DB white dwarf GD 358 through the technique of asteroseismology -- where we compare our theoretical period distributions with the observational data. The observed periods are based on over 150 hours of nearly continuous high-speed photometric data obtained with the Whole Earth Telescope. We find that GD 358 has a mass of 0.61 + or - 0.03 stellar mass with a helium layer mass of log MHe/M* = -5.70 + 0.18 or -0.30. Our results also constrain the structure of the helium/carbon transition zone and may have important consequences for our theoretical understanding of mixing and diffusion in white-dwarf stars. Our best-fit models have a luminosity of log L/Stellar Luminosity = -1.30 (+0.09 or -0.12); we use this to derive a distance of 42 + or - 3 pc, consistent with the parallax value. This distance determination is completely independent of the parallax determination, and our errors are dominated by the uncertainty in effective temperature. In the future, accurate distances to white dwarfs derived from asteroseismology will offer us the opportunity to probe properties of the interstellar medium as a function of distance and allow us to use white dwarfs as tracers of the dynamics of the local Galactic disk
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Bradley et al. (1994) studied this question.