Census of Variable Stars toward Serpens Main

TL;DR

This study conducted a comprehensive variability survey of over 11,000 stars in Serpens Main, discovering 119 new variable stars, classifying their types, and analyzing their physical and variability properties using multi-band photometry and Gaia data.

Contribution

First large-scale variability survey of Serpens Main using Pan-STARRS1 data, identifying new variables and analyzing their properties and cluster membership.

Findings

119 new variable stars discovered

Most variables are long-period giants or short-period pre-main-sequence stars

Eight eclipsing binaries identified and characterized

Abstract

We have monitored a 3 deg2 area toward Serpens Main in the Pan-STARRS1 r, i, and z bands from 2016 April to September. Light curves of more than 11,000 stars in each band were obtained, and 143 variables have been identified. Among those, 119 variables are new discoveries, while 24 variables were previously known. We present variability classes and periods of 99 stars. Of these, 81 are located in the upper giant branch, displaying long periods, while the remaining 18 variables are pre-main-sequence objects with short periods. We also identify eight eclipsing binary systems, including the known binary V0623 Ser, and derive their physical parameters. According to a clustering analysis of Gaia DR2 stars in the observed field, there are 10 variable members in Serpens Main, where six members have been classified as young stellar objects in previous studies. Here we provide color-magnitude and color-color diagrams for these variables. The color variability of most variables in the color-magnitude diagrams produce the expected displacements, while the movements of cluster members point in different directions; this behavior may be associated with accretion spots or circumstellar disks.