Discovery of pulsation in a helium-rich subdwarf B star

Abstract

Helium-rich subdwarf B (He-sdB) stars form a very small inhomogeneous group of subluminous stars showing varying degrees of helium enrichment. They have been found in the field of our galaxy as well as in globular clusters. Here we report the first discovery of pulsation in a He-sdB star – LS IV-14°116. Two pulsation periods can be clearly identified (1950 and 2900 s) and are more likely to be due to high-order non-radial g-mode oscillations than to radial or non-radial p-modes.