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

TL;DR

This paper reports the discovery of a new $eta$ Cephei variable star, ALS 3728, in the NGC 6200 cluster, characterized by its pulsation frequency, amplitude, and a notable stillstand phase, based on spectroscopic and photometric data.

Contribution

The study presents the first identification of a $eta$ Cephei star in NGC 6200 with detailed frequency and mode analysis, expanding knowledge of variable stars in this cluster.

Findings

ALS 3728 has a pulsation frequency of about 4.95 d$^{-1}$.

The star exhibits a stillstand phase before light maxima.

Mode identification was successfully applied to the dominant frequency.

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.