The Optical Gravitational Lensing Experiment. The OGLE-III Catalog of Variable Stars. X. Enigmatic Class of Double Periodic Variables in the Large Magellanic Cloud

TL;DR

This paper presents a catalog of 125 Double Periodic Variables in the Large Magellanic Cloud, highlighting their unique variability patterns and exploring potential causes for their long cycle phenomena.

Contribution

It provides the first comprehensive catalog of LMC DPVs and analyzes their properties, focusing on peculiar objects that could elucidate the long cycle mechanism.

Findings

Secondary eclipses disappear during some cycles

Primary eclipses deepen during long cycle minimum

Properties suggest circumbinary matter involvement

Abstract

The tenth part of the OGLE-III Catalog of Variable Stars contains 125 Double Periodic Variables (DPVs) from the Large Magellanic Cloud. DPVs are semi-detached binaries which show additional variability with a period around 33 times longer than the orbital period. The cause of this long cycle is not known and previous studies suggest it involves circumbinary matter. We discuss the properties of the whole sample of the LMC DPVs and put more attention to particularly interesting objects which may be crucial for verifying hypothesis explaining long cycle variability. Secondary eclipses of one of the objects disappear during some orbital cycles and primary eclipses are deeper during long cycle minimum.