Asteroseismology of ZZ Ceti stars with fully evolutionary white dwarf models. I. The impact of the uncertainties from prior evolution on the period spectrum

F. DE GERÓNIMO; ALTHAUS, L. G.; A. H. CÓRSICO; A. D. ROMERO; KEPLER, S. O.

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2017 vol. 599

0004-6361

Context. ZZ Ceti stars are pulsating white dwarfs with a carbon-oxygencore build up during the core helium burning and thermally pulsingAsymptotic Giant Branch phases. Through the interpretation of theirpulsation periods by means of asteroseismology, details about theirorigin and evolution can be inferred. The whole pulsation spectrumexhibited by ZZ Ceti stars strongly depends on the inner chemicalstructure. At present, there are several processes affecting thechemical profiles that are still not accurately determined. Aims:We present a study of the impact of the current uncertainties of thewhite dwarf formation and evolution on the expected pulsation propertiesof ZZ Ceti stars. Methods: Our analysis is based on a set ofcarbon-oxygen core white dwarf models with masses 0.548 and 0.837M⊙ that are derived from full evolutionary computationsfrom the ZAMS to the ZZ Ceti domain. We considered models in which wevaried the number of thermal pulses, the amount of overshooting, and the12C(α,γ)16O reaction rate within theiruncertainties. Results: We explore the impact of these majoruncertainties in prior evolution on the chemical structure and expectedpulsation spectrum. We find that these uncertainties yield significantchanges in the g-mode pulsation periods. Conclusions: We concludethat the uncertainties in the white dwarf progenitor evolution should betaken into account in detailed asteroseismological analyses of thesepulsating stars.