TESS photometry of extreme helium stars PV Tel and V821 Cen

Abstract

ABSTRACT PV Tel variables are extreme helium (EHe) stars known to be intrinsic light and velocity variable on characteristic time-scales of 0.1–25 d. With two exceptions, they are best described as irregular. Light curves have invariably been obtained from single-site terrestrial observatories. We present Transiting Exoplanet Survey Satellite observations of two bright EHe stars, Popper’s star (V821 Cen) and Thackeray’s star (PV Tel). PV Tel is variable on time-scales previously reported. V821 Cen is proven to be variable for the first time. Neither light curve shows any evidence of underlying regularity. Implications are considered.