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arXiv · 0812.2684

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

S. K. Randall·A. Calamida·G. Bono
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Abstract

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 mmags. A comparison between horizontal branch models and observed optical colours indicates an effective temperature of 31,500+-6,300 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.

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S. K. Randall, A. Calamida, G. Bono. 2008-12-14. Discovery of a rapidly pulsating subdwarf B star candidate in omega Cen. https://doi.org/10.1051/0004-6361%3A200811266

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