Discovery of a rapidly pulsating subdwarf B star candidate in omega Centauri

作者：Randall S K^*; Calamida A; Bono G

来源：Astronomy & Astrophysics, 2009, 494(3): 1053-1057.

DOI：10.1051/0004-6361:200811266

• stars: horizontal-branch
• stars: subdwarfs
• stars: oscillations
• Galaxy: globular clusters: general

We report the discovery of the first variable extreme horizontal branch star in a globular cluster (omega Cen). The oscillation uncovered has a period of 114 s and an amplitude of 32 mmag. A comparison between horizontal branch models and observed optical colours indicates an effective temperature of 31 500 +/- 6300 K for this star, placing it within the instability strip for rapidly oscillating B subdwarfs. The time scale and amplitude of the pulsation detected are also in line with what is expected for this type of variable, thus strengthening the case for the discovery of a new subdwarf B pulsator.

• 出版日期2009-2