Variable stars in young open star cluster NGC 7380

TL;DR

This study presents detailed time series photometry of 57 variable stars in the young open cluster NGC 7380, identifying their types, ages, and rotational properties to enhance understanding of stellar variability in young clusters.

Contribution

It provides the first comprehensive analysis of variable stars in NGC 7380, classifying their types and exploring their physical properties, including potential new classes of variables.

Findings

17 main-sequence variables, mainly B-type stars, include slowly pulsating B, β Cep, and δ Scuti stars.

14 pre-main-sequence stars are mostly younger than 5 Myr and range from 0.60 to 2.30 solar masses.

About half of the weak line T-Tauri stars are fast rotators with periods less than 2 days.

Abstract

We present time series photometry of 57 variable stars in the cluster region NGC 7380. The association of these variable stars to the cluster NGC 7380 has been established on the basis of two colour diagrams and colour-magnitude diagrams. Seventeen stars are found to be main-sequence variables, which are mainly B type stars and are classified as slowly pulsating B stars, $\beta$ Cep or $\delta$ Scuti stars. Some of them may belong to new class variables as discussed by Mowlavi et al. (2013) and Lata et al. (2014). Present sample also contains 14 pre-main-sequence stars, whose ages and masses are found to be mostly $\lesssim$ 5 Myr and range 0.60 $\lesssim M/M_{\odot} \lesssim$ 2.30 and hence should be T-Tauri stars. About half of the weak line T-Tauri stars are found to be fast rotators with a period of $\lesssim$ 2 days as compared to the classical T-Tauri stars. Some of the variables belong to the field star population.