Reference : Structural and core parameters of the hot B subdwarf KPD 1943+4058 as inferred from g...
Scientific congresses and symposiums : Unpublished conference
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/109223
Structural and core parameters of the hot B subdwarf KPD 1943+4058 as inferred from g-mode oscillations
English
Van Grootel, Valérie mailto [Laboratoire d'Astrophysique de Toulouse-Tarbes (LATT) > > > >]
Charpinet, Stéphane [ > > ]
Fontaine, Gilles [ > > ]
Brassard, Pierre [ > > ]
Green, Elizabeth M [ > > ]
Randall, Suzanna K [ > > ]
Jun-2010
No
No
International
Third Kepler Workshop
du 14 au 18 juin 2010
Aarhus Universitet
Aarhus
Danemark
[en] We present a seismic analysis of the pulsating hot B subdwarf KPD 1943+4058 (KIC 005807616) on the basis of the long-period, gravity-mode pulsations recently uncovered by Kepler. This is the first time that g-mode seismology can be exploited quantitatively for stars on the extreme horizontal branch, all previous successful seismic analyses having been confined so far to short-period, p-mode pulsators. We demonstrate that current models of hot B subdwarfs can explain quite well the observed g-mode periods, while being consistent with independent constraints provided by spectroscopy. We identify the 18 pulsations retained in our analysis as low-degree (l = 1 and 2), intermediate-order (k = −9 through −58) g-modes. The periods (frequencies) are recovered, on the average, at the 0.22% level, which is comparable to the best results obtained for p-mode pulsators. We infer the following structural and core parameters for KPD 1943+4058 : Teff = 28,050 ± 470 K, log g = 5.520 ± 0.029, M∗ = 0.4964 ± 0.0013 M⊙, log (Menv/M∗) = −2.552 ± 0.070, log (1−Mcore/M∗) = −0.366 ± 0.010, and Xcore(C+O) = 0.2612 ± 0.0080. We additionally derive the age of the star since the Zero-Age EHB 18.4 ± 1.0 Myr, the radius R = 0.2026 ± 0.0070 R⊙, the luminosity L = 22.92 ± 3.13 L⊙, the absolute magnitude MV = 4.21 ± 0.11, the reddening index E(B − V ) = 0.094 ± 0.017, and the distance d = 1183 ± 93 pc.
http://hdl.handle.net/2268/109223

File(s) associated to this reference

Fulltext file(s):

FileCommentaryVersionSizeAccess
Open access
Aarhus_VanGrootel.pdfAuthor postprint5.66 MBView/Open

Bookmark and Share SFX Query

All documents in ORBi are protected by a user license.