ON THE FORMATION OF HOT DQ WHITE DWARFS
Open Access
- 11 February 2009
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 693 (1), L23-L26
- https://doi.org/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 for 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 PG 1159 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 PG 1159 star H1504+65, is plausible.Keywords
This publication has 21 references indexed in Scilit:
- The Pulsating White Dwarf StarsPublications of the Astronomical Society of the Pacific, 2008
- Hot DQ White Dwarfs: Something DifferentThe Astrophysical Journal, 2008
- The temporal changes of the pulsational periods of the pre-white dwarf PG 1159-035Astronomy & Astrophysics, 2008
- SDSS J142625.71+575218.3: The First Pulsating White Dwarf with a Large Detectable Magnetic FieldThe Astrophysical Journal, 2008
- Evidence of Thin Helium Envelopes in PG 1159 StarsThe Astrophysical Journal, 2008
- Asteroseismological measurements on PG 1159-035, the prototype of the GW Virginis variable starsAstronomy & Astrophysics, 2007
- White dwarf stars with carbon atmospheresNature, 2007
- Updated Electron‐Conduction Opacities: The Impact on Low‐Mass Stellar ModelsThe Astrophysical Journal, 2007
- The formation and evolution of hydrogen-deficient post-AGB white dwarfs: The emerging chemical profile and the expectations for the PG 1159-DB-DQ evolutionary connectionAstronomy & Astrophysics, 2005
- Standard and nonstandard plasma neutrino emission revisitedThe Astrophysical Journal, 1994