TYC 1031 01262 1: The First Known Galactic Eclipsing Binary with a Type II Cepheid Component

TL;DR

This paper reports the discovery of the first known Galactic eclipsing binary system containing a Type II Cepheid, with detailed observations revealing its pulsation and orbital periods, and suggesting non-spherical stellar components.

Contribution

It introduces the first Galactic eclipsing binary with a Type II Cepheid, providing new insights into such rare stellar systems.

Findings

Shortest orbital period among known Cepheid binaries

Pulsations dominate brightness variations

Components likely non-spherical

Abstract

We present the discovery and CCD observations of the first eclipsing binary with a Type II Cepheid component in our Galaxy. The pulsation and orbital periods are found to be 4.1523 and 51.38 days, respectively, i.e. this variable is a system with the shortest orbital period among known Cepheid binaries. Pulsations dominate the brightness variations. The eclipses are assumed to be partial. The EB-subtype eclipsing light curve permits to believe that the binary's components are non-spherical.