New {\beta} Cephei variable in the Southern open cluster NGC 6200: ALS 3728

Abstract

We report the evidence of a new $\beta$ Cephei type variable located in the Southern open cluster \astrobj{NGC 6200}: \astrobj{ALS 3728}. Spectroscopic and photometric observations of NGC\,6200 stars were carried out at the South African Astronomical Observatory (SAAO) in 2011. It was found that \astrobj{ALS 3728} has a frequency of about 4.95 d$^{-1}$ with highest amplitude. The star also shows a remarkable stillstand phase just before its light maxima which is a typical characteristic occurring among these type of stars. Furthermore, a mode identification is applied for the dominant frequency that is calculated from the Fourier analysis.