Query : 2012A&A...541A..42C

2012A&A...541A..42C - Astronomy and Astrophysics, volume 541A, 42-42 (2012/5-1)

Asteroseismology of the Kepler V777 Herculis variable white dwarf with fully evolutionary models.


Abstract (from CDS):

DBV stars are pulsating white dwarfs with atmospheres rich in He. Asteroseismology of DBV stars can provide valuable clues about the origin, structure and evolution of hydrogen-deficient white dwarfs, and may allow to study neutrino and axion physics. Recently, a new DBV star, KIC 8626021, has been discovered in the field of the Kepler spacecraft. It is expected that further monitoring of this star in the next years will enable astronomers to determine its detailed asteroseismic profile. We perform an asteroseismological analysis of KIC 8626021 on the basis of fully evolutionary DB white-dwarf models. We employ a complete set of evolutionary DB white-dwarf structures covering a wide range of effective temperatures and stellar masses. They have been obtained on the basis of a complete treatment of the evolutionary history of progenitors stars. We compute g-mode adiabatic pulsation periods for this set of models and compare them with the pulsation properties exhibited by KIC 8626021.On the basis of the mean period spacing of the star, we found that the stellar mass should be substantially larger than spectroscopy indicates. From period-to-period fits we found an asteroseismological model characterized by an effective temperature much higher than the spectroscopic estimate.In agreement with a recent asteroseismological analysis of this star by other authors, we conclude that KIC 8626021 is located near the blue edge of the DBV instability strip, contrarily to spectroscopic predictions. We also conclude that the mass of KIC 8626021 should be substantially larger than thought.

Abstract Copyright:

Journal keyword(s): stars: interiors - stars: oscillations - asteroseismology - white dwarfs - stars: evolution

Simbad objects: 5

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Number of rows : 5
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
1 V* GW Vir WD* 12 01 45.9731868264 -03 45 40.628670300   14.87 15.04     DOQZ1 475 0
2 V* EM UMa WD* 13 53 09.9687043752 +48 40 21.171407268   16.5   17.0   DB2 95 0
3 GD 358 WD* 16 47 18.3925183824 +32 28 32.862804384 12.511 13.530 13.653 13.752 13.852 DB2 334 0
4 GALEX J192904.6+444708 WD* 19 29 04.6788742824 +44 47 09.028359420   18.3   18.5   DB 32 0
5 V* QU Tel WD* 20 09 40.1871967824 -52 25 15.864452508 14.51 15.25 15.03     DB2 51 0

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