On the binary origin of FS CMa stars: young massive clusters as test beds

TL;DR

This study investigates the binary origin of FS CMa stars by examining their presence in young massive clusters, using photometric surveys to identify candidates and testing hypotheses about their formation in dense stellar environments.

Contribution

It provides the first systematic search for FS CMa stars in young massive clusters using Paschen-$eta$ photometry, discovering new candidates and discussing formation scenarios.

Findings

Two confirmed FS CMa stars in YMCs

Three new candidates identified in the Galactic Center

A new candidate found in the Quintuplet cluster

Abstract

FS CMa stars are low-luminosity objects showing the B[e] phenomenon whose evolutionary origin is yet to be unraveled. Various binary-related hypotheses have been recently proposed, two of them involving the spiral-in evolution of the binary orbit. The latter occurs more often in dense stellar environments like young massive clusters (YMCs). Hence, a systematic study of FS CMa stars in YMCs would be crucial to find out how these objects are created. In YMCs, two FS CMa stars have been confirmed and three candidates have been found through a search method based on narrow-band photometry at Paschen-$\alpha$ and the neighboring continuum. We apply this method to archival data from the Paschen-$\alpha$ survey of the Galactic Center region, yielding a new candidate in the Quintuplet cluster. Limitations of this method and other alternatives are briefly discussed.