Optical/IR studies of Be stars in NGC 6834 with emphasis on two specific stars

Abstract

We present optical and infrared photometric and spectroscopic studies of two Be stars in the 70-80-Myr-old open cluster NGC 6834. NGC 6834(1) has been reported as a binary from speckle interferometric studies whereas NGC 6834(2) may possibly be a γ Cas-like variable. Infrared photometry and spectroscopy from the United Kingdom Infrared Telescope (UKIRT), and optical data from various facilities are combined with archival data to understand the nature of these candidates. High signal-to-noise near-IR spectra obtained from UKIRT have enabled us to study the optical depth effects in the hydrogen emission lines of these stars. We have explored the spectral classification scheme based on the intensity of emission lines in the H and K bands and contrasted it with the conventional classification based on the intensity of hydrogen and helium absorption lines. This work also presents hitherto unavailable UBV CCD photometry of NGC 6834, from which the evolutionary state of the Be stars is identified.

Massive Stars in Molecular Clouds Rich in High-energy Sources: The Bridge of G332.809-0.132 and CS 78 in NGC 6334

“…All but NGC 6834 are random superpositions. NGC 6834 is located at a likely distance of 3.1 kpc (Mathew et al 2014), but an estimate of the distance to SNR G065.7+01.2 is not available (Acero et al 2016). 2 and 4.…”