Mode Identification in a Pulsating Subdwarf B Star EPIC 212707862 Observed with K2

• Autorzy: Bachulski S. , Baran A. S. , Jeffery C. S. , Østensen R. H. , Reed M. D. , Telting J. H. , Kuutma T.
• Języki publikacji: EN

Abstrakty

EN

We present an analysis of K2 observations of EPIC 212707862, a pulsating subdwarf B star. We detected 13 significant frequencies from an 81 day run during Campaign 6. Our goal was to find features that could help us to identify pulsation modes. We could not identify any multiplets, which would also have enabled us to precisely derive a rotation period. Based on amplitude modulation we estimated that period to be around 80 days. We found two period-spacing sequences, and successfully identified modal degrees for 11 out of 13 detected frequencies. We assigned six of them to l=1, and another five to l=2. These results will facilitate future theoretical modeling. This star brings to 19 the number of pulsating subdwarf B stars observed with K2. Radial velocities obtained to date and the spectral energy distribution are consistent with EPIC 212707862 being a single hot subdwarf. Analysis of the spectrum gives atmospheric parameters: T_eff=28 298±162 K, log g[cm/s²]=5.479±0.025 and log (n(He)/n(H))=-2.752±0.069.

Słowa kluczowe

EN

subdwarfs; stars: oscillations; asteroseismology

• Wydawca: Copernicus Foundation for Polish Astronomy
• Czasopismo: Acta Astronomica
• Rocznik: 2016
• Tom: Vol. 66, No. 4
• Strony: 455--467
• Opis fizyczny: Bibliogr. 29 poz., rys., tab., wykr.

Twórcy

autor

Bachulski S.

• Pedagogical University of Cracow, Mt. Suhora Observatory, ul. Podchorążych 2, 30-084 Cracow, Poland

autor

Baran A. S.

• Pedagogical University of Cracow, Mt. Suhora Observatory, ul. Podchorążych 2, 30-084 Cracow, Poland

autor

Jeffery C. S.

• Armagh Observatory and Planetarium, College Hill, Armagh BT61 9DG, United Kingdom,

autor

Østensen R. H.

• Missuori State University, Department of Physics, Astronomy, and Materials Science, 901 S. National Av., Springfield, MO 65897, USA

autor

Reed M. D.

• Missuori State University, Department of Physics, Astronomy, and Materials Science, 901 S. National Av., Springfield, MO 65897, USA

autor

Telting J. H.

• Nordic Optical Telescope, Rambla Josè Ana Fernàndez Pèrez 7, 38711 Breña Baja, Spain

autor

Kuutma T.

• Nordic Optical Telescope, Rambla Josè Ana Fernàndez Pèrez 7, 38711 Breña Baja, Spain
• Tartu Observatory: Observatooriumi 1, 61602 Tøravere, Estonia

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