Query : 2017A&A...598A.109G

2017A&A...598A.109G - Astronomy and Astrophysics, volume 598A, 109-109 (2017/2-1)

The potential of asteroseismology for probing the core chemical stratification in white dwarf stars.


Abstract (from CDS):

Context. The details of the C/O core structure in white dwarf stars has mostly remained inaccessible to the technique of asteroseismology, despite several attempts carried out in the past.
Aims. We aim to re-assess the potential of asteroseismology for probing the chemical stratification in white dwarf cores, in light of new highly efficient tools recently developed for that purpose.
Methods. Using the forward modeling approach and a new parameterization for the core chemical stratification in ZZ Ceti stars, we tested several situations typical of the usually limited constraints available, such as small numbers of observed independent modes, to carry out asteroseismology of these stars.
Results. We find that, even with a limited number of modes, the core chemical stratification (in particular, the location of the steep chemical transitions expected in the oxygen profile) can be determined quite precisely due to the significant sensitivity of some confined modes to partial reflexion (trapping) effects. These effects are similar to the well known trapping induced by the shallower chemical transitions at the edge of the core and at the bottom of the H-rich envelope. We also find that success to unravel the core structure depends on the information content of the available seismic data. In some cases, it may not be possible to isolate a unique, well-defined seismic solution and the problem remains degenerate.
Conclusions. Our results establish that constraining the core chemical stratification in white dwarf stars based solely on asteroseismology is possible, an opportunity that we have begun to exploit.

Abstract Copyright: © ESO, 2017

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

Simbad objects: 3

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Number of rows : 3
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 V* ZZ Cet WD* 01 36 13.6153974672 -11 20 32.632874601   14.328 14.16 14.4   DA4.0 281 0
2 GD 165 WD* 14 24 39.1495824408 +09 17 14.160753960   14.46 14.32 14.6 14.91 DA4.1 160 0
3 GD 358 WD* 16 47 18.3925183824 +32 28 32.862804384 12.511 13.530 13.653 13.752 13.852 DB2 343 0

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