Eclipsing Binaries with Classical Cepheid Component in the Magellanic System

TL;DR

This paper catalogs eclipsing binary systems with classical Cepheid components in the Magellanic System, discovering new candidates and demonstrating the use of light-time effect analysis to confirm binarity.

Contribution

It extends the list of known eclipsing Cepheids in the Magellanic System and applies light-time effect analysis to identify binarity in these systems.

Findings

Discovered four new eclipsing Cepheid candidates in OGLE-IV data.

Detected light-time effect in OGLE-LMC-CEP-1812 confirming binarity.

Identified a single-eclipse event with evidence of binarity in OGLE-SMC-CEP-3235.

Abstract

We present a census of eclipsing binary systems with classical Cepheid as a component. All such systems known were found in the OGLE collection of classical Cepheids in the Magellanic System. We extend the list of potential candidates adding four new objects found in the OGLE-IV photometric data. One of the new Cepheids in the eclipsing system, OGLE-SMC-CEP-3235, revealed only one eclipse during 15 years of the OGLE photometric monitoring. However, it additionally shows very well pronounced light-time effect indicating that the binarity is real. We also search for the light-time effect in other known eclipsing Cepheids and we clearly detect it in OGLE-LMC-CEP-1812. We discuss application of this tool for the search for Cepheids in non-eclipsing binary systems.