On the formation of hot DQ white dwarfs
arXiv:0901.1836 · doi:10.1088/0004-637X/693/1/L23
Abstract
We present the first full evolutionary calculations aimed at exploring the origin of hot DQ white dwarfs. These calculations consistently cover the whole evolution from the born-again stage to the white dwarf cooling track. Our calculations provide strong support to the diffusive/convective-mixing picture for the formation of hot DQs. We find that the hot DQ stage is a short-lived stage and that the range of effective temperatures where hot DQ stars are found can be accounted for by different masses of residual helium and/or different initial stellar masses. In the frame of this scenario, a correlation between the effective temperature and the surface carbon abundance in DQs should be expected, with the largest carbon abundances expected in the hottest DQs. From our calculations, we suggest that most of the hot DQs could be the cooler descendants of some PG1159 stars characterized by He-rich envelopes markedly smaller than those predicted by the standard theory of stellar evolution. At least for one hot DQ, the high-gravity white dwarf SDSS J142625.70+575218.4, an evolutionary link between this star and the massive PG1159 star H1504+65 is plausible.
arXiv comment4 pages, 2 figures. To be published in The Astrophysical Journal Letters
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- On the Spectral Evolution of Hot White Dwarf Stars. III. The PG 1159DODBDQ Evolutionary Channel Revisited
- Asteroseismology of the Kepler V777 Her variable white dwarf with fully evolutionary models
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- Photometric variability in a warm, strongly magnetic DQ white dwarf, SDSS J103655.39+652252.2
- A New Small-Amplitude Variable Hot DQ White Dwarf
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- Hot C-rich white dwarfs: testing the DB-DQ transition through pulsations
- A hot white dwarf merger remnant revealed by an ultraviolet detection of carbon