Formation and evolution of hydrogen-deficient post AGB white dwarfs

ALTHAUS L. G.; PANEI J. A.; CÓRSICO A. H.; GARCÍA-BERRO E.; SCÓCCOLA C. G.

PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC

Astronomical Society of the Pacific

Lugar: San Francisco, EEUU; Año: 2005 vol. 334 p. 61 - 64

0004-6280

We explore the formation and evolution of hydrogen-deficient post-AGB white dwarf (WD) stars. To this end, we compute the complete evolution of an initially $2.7 , M_{sun}$ star from the ZAMS through the thermally pulsing and mass-loss phases, the born-again stage to the WD stage. A time-dependent scheme for the simultaneous treatment of abundance changes caused by nuclear reactions, diffusive overshooting, salt fingers and convection is considered. In addition, microscopic element diffusion is taken into account during the white dwarf evolution. Relevant aspects for PG1159 stars and DB WD evolution are studied in the frame of these new evolutionary models that take into account the history of the white dwarf progenitor. The scope of the calculations is extended to the domain of the helium-rich, carbon-contaminated DQ white dwarfs with the aim of exploring the plausibility of the evolutionary connection PG1159-DB-DQ.