Be Stars in the Open Cluster NGC 6830

TL;DR

This study discovers and confirms multiple Be stars in the open cluster NGC 6830 using photometric and spectroscopic methods, highlighting the efficiency of the SED-Machine for future surveys.

Contribution

It reports the discovery of new Be stars and demonstrates the effectiveness of the SED-Machine spectrograph for rapid Be star identification.

Findings

Three Be stars confirmed with H-alpha emission > -10 Å

Two additional objects observed with SED-Machine show strong H-alpha emission

High efficiency of SED-Machine for future Be star surveys

Abstract

We report the discovery of 2 new Be stars, and re-identify one known Be star in the open cluster NGC 6830. Eleven H-alpha emitters were discovered using the H-alpha imaging photometry of the Palomar Transient Factory Survey. Stellar membership of the candidates was verified with photometric and kinematic information using 2MASS data and proper motions. The spectroscopic confirmation was carried out by using the Shane 3-m telescope at Lick observatory. Based on their spectral types, three H-alpha emitters were confirmed as Be stars with H-alpha equivalent widths > -10 Angstrom. Two objects were also observed by the new spectrograph SED-Machine on the Palomar 60 inch Telescope. The SED-Machine results show strong H-alpha emission lines, which are consistent with the results of the Lick observations. The high efficiency of the SED-Machine can provide rapid observations for Be stars in a comprehensive survey in the future.