Evryscope-South Survey of Upper- and Pre-main Sequence Solar Neighborhood Stars

TL;DR

This study utilizes Evryscope-South data to identify and analyze variable young stars on the upper- and pre-main sequence, discovering new eclipsing binaries and providing insights into stellar evolution.

Contribution

First large-scale survey of young UMS and PMS stars using Evryscope-South, discovering 237 new variables including 84 young eclipsing binaries.

Findings

Identified 615 variable stars, 237 new discoveries.

Discovered a highly eccentric binary system.

Estimated ages for PMS variables range from 1 to 23 Myr.

Abstract

Using photometric data collected by Evryscope-South, we search for nearby young variable systems on the upper-main sequence (UMS) and pre-main sequence (PMS). The Evryscopes are all-sky high-cadence telescope arrays operating in the Northern and Southern hemispheres. We base our search on a Gaia-selected catalog of young neighborhood upper- and pre-main sequence stars which were chosen through both astrometric and photometric criteria. We analyze 44,971 Evryscope-South light curves in search of variability. We recover 615 variables, with 378 previously known, and 237 new discoveries including 84 young eclipsing binary (EB) candidates. We discover a new highly eccentric binary system and recover a further four previously known systems, with periods ranging from 299 to 674 hr. We find 158 long-period (>50 hr) candidate EB systems, 9 from the PMS and 149 from the UMS, which will allow constraints on the mass-radius-age relation. These long-period EBs include a 179.3 hr PMS system and a 867.8 hr system from the UMS. For PMS variable candidates we estimate system ages, which range from 1 to 23 Myr for non-EBs and from 2 to 17 Myr for EBs. Other non-EB discoveries that show intrinsic variability will allow relationships between stellar rotation rates, ages, activity, and mass to be characterized.