Extreme adaptive optics astrometry of R136. Searching for high proper motion stars
arXiv:2104.12819 · doi:10.1051/0004-6361/202140668
Abstract
We compared high-contrast near-infrared images of the core of R136 taken by VLT/SPHERE, in two epochs separated by 3.06 years. For the first time we monitored the dynamics of the detected sources in the core of R136 from a ground-based telescope with adaptive optics. The aim of these observations was to search for High prOper Motion cAndidates (HOMAs) in the central region of R136 (r<6") where it has been challenging for other instruments. Two bright sources (K<15mag and V<16mag) are located near R136a1 and R136c (massive WR stars) and have been identified as potential HOMAs. These sources have significantly shifted in the images with respect to the mean shift of all reliable detected sources and their neighbours, and six times their own astrometric errors. We calculate their proper motions to be 1.36\pm0.22 mas/yr (321\pm52 km/s) and 1.15\pm0.11 mas/yr (273\pm26 km/s). We discuss different possible scenarios to explain the magnitude of such extreme proper motions, and argue for the necessity to conduct future observations to conclude on the nature of HOMAs in the core of R136.
Accepted to be published in A&A/Letter. catalogue of the reliable-consistent sources are available online via CDS
References in corpus (5)
- An eclipsing binary distance to the Large Magellanic Cloud accurate to 2 per cent
- The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 Msun stellar mass limit
- The R136 star cluster dissected with Hubble Space Telescope/STIS. II. Physical properties of the most massive stars in R136
- An X-ray Survey of Wolf-Rayet Stars in the Magellanic Clouds. I. The Chandra ACIS Dataset
- High contrast and resolution near infrared photometry of the core of R136