SIMBAD references

Using numerical models, we investigate the possibilities of observable effects in the frequency distribution of the normal modes of the pulsating DB-type white dwarfs caused by different evolutionary paths. We find the average period spacing of consecutive radial overtones to be much shorter and the periods of the low k modes to be much longer for DB models resulting from the binary evolution than for those arising from evolution of a single star. Then we compare our models to the GD 358 data and conclude that this star either went through extremely long accretion phase, if it has developed from a binary system, or it is the result of evolution of a single star.