Symbiotic stars in Galactic open clusters

TL;DR

This study investigates the potential membership of symbiotic stars in Galactic open clusters to better understand their ages, finding one confirmed case and raising doubts about others, thereby aiding in modeling these binary systems.

Contribution

It presents the first systematic search for symbiotic stars within Galactic open clusters, providing new insights into their ages and properties.

Findings

CQ Dra is confirmed as a member of an old open cluster.

Most other candidates have uncertain cluster membership.

The study enhances understanding of symbiotic star ages and environments.

Abstract

The age determination of symbiotic stars is essential to put further constraints on models explaining these binary systems. In the Galactic field, this is especially problematic because of several limitations due to reddening estimations, for example. We searched for symbiotic stars as members of Galactic open clusters for which the age and overall metallicity can be determined in a statistical sense. The most recent lists of well-established and candidate symbiotic stars and open clusters were matched, and we found seven good candidates from which the well-established symbiotic star CQ Dra seems to be a true member of the old open cluster HSC 1224. The colour-magnitude diagrams for the other candidates raise some doubts about membership.