Discovery of a rapidly pulsating subdwarf B star candidate in $mathsf{omega}$ Centauri

摘要

We report the discovery of the first variable extreme horizontal branch star in a globular cluster(Cen). The oscillation uncovered has a period of 114 s and an amplitude of 32mmag. A comparison between horizontal branch models and observed optical colours indicates an effective temperature of 315006300K for this star, placing it within the instability strip for rapidly oscillating Bsubdwarfs. 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 Bpulsator. Key words: stars: horizontal-branch - stars: subdwarfs - stars: oscillations - Galaxy: globular clusters: general