Contributed Talk - Splinter TimeDomain

Wednesday, 15 September 2021, 17:23   (virtual TimeD)

One thousand heartbeat stars from the OGLE project

Marcin Wrona, Milena Ratajczak, Piotr Kołaczek-Szymański, and The OGLE Team
Astronomical Observatory, University of Warsaw

Heartbeat stars (HBSs) are a subclass of the ellipsoidal variables with an eccentric orbit. Brightness variations of those systems are mainly caused by tidal deformation of at least one component and they are most clearly visible near the periastron passage. The name of this type of variable stars refers to the characteristic shape of the light curve, which is similar to an electrocardiogram signature. Here, we present the catalog and the results of our analysis of 996 HBS candidates cataloged in the OGLE Collection of Variable Stars. The OGLE project (Optical Gravitational Lensing Experiment) is a long-term sky survey that focuses on searching for any kind of photometric variability. It uses the 1.3-meter Warsaw Telescope, located at Las Campanas Observatory, Chile. Our sample of HBSs consists of 515 stars found toward the Galactic bulge, 441 and 40 located in the Large and Small Magellanic Cloud, respectively. The identified systems may be divided into two separate groups of different evolutionary status. The first group of about 90 systems, with a short orbital period (P<50 days), consist of an early-type primary star lying on or near the main sequence. The second group of about 900 systems, with a long orbital period (P>100 days), contain a red giant.