Probing the Structure of Kepler ZZ Ceti Stars with Full Evolutionary Models-based Asteroseismology

A. D. ROMERO; A. H. CÓRSICO

ASTROPHYSICAL JOURNAL

IOP PUBLISHING LTD

Lugar: Londres; Año: 2017 vol. 851

0004-637X

We present an asteroseismological analysis of four ZZ Ceti starsobserved with the Kepler spacecraft: GD 1212, SDSS J113655.17+040952.6,KIC 11911480, and KIC 4552982, based on a grid of full evolutionarymodels of DA white dwarf (WD) stars. We employ a grid ofcarbon?oxygen core models, characterized by a detailed andconsistent chemical inner profile for the core and the envelope. Inaddition to the observed periods, we take into account other informationfrom the observational data, such as amplitudes, rotational splittings,and period spacing, as well as photometry and spectroscopy. For eachstar, we present an asteroseismological model that closely reproducestheir observed properties. The asteroseismological stellar mass andeffective temperature of the target stars are (0.632+/- 0.027{M}ȯ , 10737 ± 73 K) for GD 1212, (0.745+/- 0.007{M}ȯ , 11110 ± 69 K) for KIC 4552982, (0.5480+/-0.01 {M}ȯ , 12,721 ± 228 K) for KIC11911480, and(0.570+/- 0.01 {M}ȯ , 12,060 ± 300 K) for SDSSJ113655.17+040952.6. In general, the asteroseismological values are ingood agreement with the spectroscopy. For KIC 11911480 and SDSSJ113655.17+040952.6 we derive a similar seismological mass, but thehydrogen envelope is an order of magnitude thinner for SDSSJ113655.17+040952.6, which is part of a binary system and went through acommon envelope phase.