The VMC survey - XXXVI. Young stellar variability in the Large Magellanic Cloud
Abstract
Studies of young stellar objects (YSOs) in the Galaxy have found that a significant fraction exhibits photometric variability. However, no systematic investigation has been conducted on the variability of extragalactic YSOs. Here we present the first variability study of massive YSOs in an Ks∼ 18.5 region of the Large Magellanic Cloud (LMC). The aim is to investigate whether the different environmental conditions in the metal-poor LMC (∼ 0.4-0.5 Z⊙) have an impact on the variability characteristics. Multi-epoch near-infrared (NIR) photometry was obtained from the VISTA Survey of the Magellanic Clouds (VMC) and our own monitoring campaign using the VISTA telescope. By applying a reduced χ2-analysis, stellar variability was identified. We found 3062 candidate variable stars from a population of 362 425 stars detected. Based on several Spitzer studies, we compiled a sample of high-reliability massive YSOs: a total of 173 massive YSOs have NIR counterparts (down to Ks∼ 18.5mag) in the VMC catalogue, of which 39 display significant (>3σ) variability. They have been classified as eruptive, fader, dipper, short-term variable, and long-period variable YSOs based mostly on the appearance of their Ks-band light curves. The majority of YSOs are aperiodic; only five YSOs exhibit periodic light curves. The observed amplitudes are comparable or smaller than those for Galactic YSOs (only two Magellanic YSOs exhibit ΔKs > 1 mag), not what would have been expected from the typically larger mass accretion rates observed in the Magellanic Clouds.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 2020
- DOI:
- 10.1093/mnras/staa626
- arXiv:
- arXiv:2002.12291
- Bibcode:
- 2020MNRAS.494..458Z
- Keywords:
-
- techniques: photometric;
- stars: pre-main-sequence;
- stars: variables: general;
- galaxies: individual: LMC;
- infrared: stars;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted for publication in MNRAS, 32 pages, 24 figures