Propiedades evolutivas y pulsacionales de estrellas de enanas blancas de baja masa con núcleos de oxígeno resultantes de sistemas binarios interactuantes.

ALTHAUS L. G.; CÓRSICO A. H.; GAUSTCHY A.; HAN Z.; SERENELLI A. M.; PANEI J. A.

La Plata, Bs. As., Argentina

Congreso; XLVI Reunión Anual de la Asociación Argentina de Astronomía; 2003

Asociación Argentina de Astronomía

The presente work is designed to explore the evolutionary and pulsational properties of low-mass white dwwarfs with carbon/oxygen cores. In particular, we follow the evolution of a 0.33 solar masses white dwarf remnant in a self-consistent way with the prediction of nuclear burning, element diffusion and history of the white dwarf pregenitor. The evolutionary stages prior to white dwarf formation are also fully accounted for by computing the conservative binary evolution of an initially 2.5 solar masses Pop. Istar with a 1.25 solar masses companion, and orbital period of 3 days. Evolution is followed down to the domain of the ZZ Ceti stars on the white dwarf colling branch. We find that the chemical diffusion induces rhe occurence of an additional hydrogen thermonuclear flash which leads to stellar models with thin hydrogen envelopes. As a result, a fast cooling is encountered to advanced stages of evolution. In addition, we explore the adiabatic pulsational properties of the resulting white dwarf models. As compared with their helium-corecounterparts, low mass oxygen-core white dwarfs are characterized by a pulsational spectrum much more featured, an aspect which could eventually be used for distinguishing both types of stars if low-mass white dwarfs were in fact found to pulsate as ZZ ceti - type variables. Finally, we perform a non-adiabatic pulsational analysis on the resulting carbon/oxygen low-mass white dwarf models.