AT LAST-A V777 HER PULSATOR IN THE KEPLER FIELD

作者：Ostensen R H^*; Bloemen S; Vuckovic M; Aerts C; Oreiro R; Kinemuchi K; Still M; Koester D

来源：Astrophysical Journal Letters, 2011, 736(2): L39.

DOI：10.1088/2041-8205/736/2/L39

• stars: individual (GALEX J192904.6+444708)
• stars: oscillations
• stars: variables: general
• white dwarfs

We present the discovery of the first-and so far the only-pulsating white dwarf star located in the field of view of the Kepler spacecraft. During our ongoing effort to search for compact pulsator candidates that can benefit from the near-continuous coverage of Kepler, we recently identified a faint DB star from spectroscopy obtained with the William Herschel Telescope. After establishing its physical parameters to be T-eff = 24,950 K and log g = 7.91 dex, placing it right in the middle of the V777 Her instability strip, we immediately submitted the target for follow-up space observations. The Kepler light curve reveals a pulsation spectrum consisting of five modes that follow a sequence roughly equally spaced in period with a mean spacing of 37 s. The three strongest modes show a triplet structure with a mean splitting of 3.3 mu Hz. We conclude that this object is a V777 Her pulsator with a mass of similar to 0.56 M-circle dot, and very similar to the class prototype.

• 出版日期2011-8-1