Study of Classical Be stars in open clusters older than 100 Myr

TL;DR

This study surveys open clusters older than 100 Myr to identify Classical Be stars, discovering 13 such stars, including a new detection, and analyzing their spectral types and disc properties.

Contribution

It provides the first systematic identification of Classical Be stars in clusters older than 100 Myr, including a new detection and analysis of their spectral and disc characteristics.

Findings

13 CBe stars identified in 11 clusters, including one new detection.

CBe stars exhibit Hα emission and IR excess, confirming gaseous discs.

Spectral types range from B0.5 to B8, peaking near late B-types.

Abstract

We performed the slitless spectroscopic survey to identify Classical (CBe) stars in open clusters older than 100 Myr. Observing a sample of 71 open clusters, we identified 13 CBe stars in 11 open clusters, one of, which (TYC 2679-432-1) is a new detection. The 13 CBe stars show both H$\alpha$ in emission and IR excess, which confirm that they possess gaseous circumstellar discs. Two more CBe stars are found to exhibit H$\alpha$ in absorption for the first time, indicating that might be passing through disc-less episode presently. The spectral type estimation is done for all these 15 stars and it is noticed that they belong to B0.5 -- B8 type. Moreover, we found that the distribution of our sample is peaking near late B-types as expected.