Stellar Variability in a Forming Massive Star Cluster
Journal article, 2020

We present a near-infrared (NIR) variability analysis for a 6′ 6′ region, which encompasses the massive protocluster G286.21+0.17. The total sample comprises more than 5000 objects, of which 562 show signs of a circumstellar disk based on their infrared colors. The data includes Hubble Space Telescope observations taken in two epochs separated by 3 yr in the F110W and F160W bands. 363 objects (7% of the sample) exhibit NIR variability at a significant level (Stetson index >1.7), and a higher variability fraction (14%) is found for the young stellar objects with disk excesses. We identified four high amplitude (>0.6 mag) variables seen in both NIR bands. Follow-up and archival observations of the most variable object in this survey (G286.2032+0.1740) reveal a rising light curve over 8 yr from 2011 to 2019, with a K band brightening of 3.5 mag. Overall the temporal behavior of G286.2032+0.1740 resembles that of typical FU Ori objects; however, its pre-burst luminosity indicates it has a very low mass (<0.12 M o˙), making it an extreme case of an outburst event that is still ongoing.


Yu Cheng

University of Virginia

Morten Andersen

Gemini Observatory South

Jonathan Tan

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

University of Virginia

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 897 1 51

Subject Categories

Astronomy, Astrophysics and Cosmology

Environmental Sciences

Computer Vision and Robotics (Autonomous Systems)



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