Reference : Probing the cores of Extreme Horizontal Branch stars by gravity-mode seismology
Scientific congresses and symposiums : Unpublished conference
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
Probing the cores of Extreme Horizontal Branch stars by gravity-mode seismology
Van Grootel, Valérie mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie >]
Charpinet, Stéphane [ > > ]
Fontaine, Gilles [ > > ]
Brassard, Pierre [ > > ]
Green, Elizabeth M [ > > ]
Second CoRoT Symposium
du 14 au 17 juin 2011
Laboratoire d'Astrophysique de Marseille
[en] We present a seismic analysis of the pulsating subdwarf B star KPD 0629-0016 on the basis of the long-period, gravity-mode pulsations uncovered by CoRoT. Thanks to space- based facilities, g-mode seismology can now be exploited quantitatively for stars on the ex- treme horizontal branch, an objective undermined so far by the limitations of ground-based observations. The optimal seismic model offers an excellent fit, with a relative dispersion of 0.23%, to the 18 observed periods identified with theoretical modes of degrees l =1 and 2. The inferred structural parameters for KPD 0629–0016 include the total stellar mass, the thickness of the H-rich envelope, and, thanks to the sensitivity of g-modes, the size and the composition of the convective core. Our results suggest that extra mixing processes shape the helium-burning cores, that are representative of all horizontal branch stars in general, an intermediate and underrated stage of stellar evolution.

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