ANDICAM I and J band monitoring of bright inner Galactic late-type stars

TL;DR

This study presents time-series I and J band photometry of 57 probable Galactic red supergiant stars, revealing significant correlated variability and short periods, and confirms their classification distinct from AGB stars.

Contribution

First detailed I and J band variability analysis of a large sample of Galactic RSG candidates, establishing their photometric behavior and period-luminosity relation.

Findings

38% of stars show significant variability

Correlated I and J band variations with a ratio of 2.2

Detected short periods ranging from 167 to 433 days

Abstract

Time-series photometry in I and J band of 57 inner Galactic late-type stars, highly-probable red supergiant (RSG) stars, is here presented. 38% of the sample presents significant photometric variations. The variations in I and J band appear to be correlated, with DeltaI = DeltaJ x 2.2, DeltaI variations ranging from 0.04-1.08 mag, DeltaJ variations from 0.03-0.52 mag. New short periods (< 1000 d) could be estimated for 8 stars and range from 167-433 d. This work confirms that the sample is not contaminated by large-amplitude Asymptotic Giant Branch (AGB) stars. Furthermore, despite the large errors in distance, the period-luminosity diagram suggests that the sample is populating the same sequence as the known Galactic RSGs.