Multi-Epoch BVRI Photometry of Luminous Stars in M31 and M33

TL;DR

This study provides four years of BVRI photometric data for 199 luminous stars in M31 and M33, revealing significant variability in 33 stars, including classic LBVs during outbursts, enhancing understanding of massive star behavior.

Contribution

First multi-epoch BVRI photometry survey of luminous stars in M31 and M33, identifying variable stars and capturing LBV outbursts over four years.

Findings

33 stars show significant variability

At least two LBVs caught in S Doradus outbursts

Photometry achieved high precision down to magnitude 19.0-19.5

Abstract

We present the first four years of BVRI photometry from an on-going survey to annually monitor the photometric behavior of evolved luminous stars in M31 and M33. Photometry was measured for 199 stars at multiple epochs, including 9 classic Luminous Blue Variables (LBVs), 22 LBV candidates, 10 post-RGB A/F type hypergiants, and 18 B[e] supergiants. At all epochs the brightness is measured in V and at least one other band to a precision of 0.04 -- 0.10 magnitudes down to a limiting magnitude of 19.0 -- 19.5. Thirty three (33) stars in our survey exhibit significant variability, including at least two classic LBVs caught in S Doradus type outbursts. A hyper-linked version of the photometry catalog is at: http://go.uis.edu/m31m33photcat/.