The VLT-FLAMES Tarantula Survey. VI. Evidence for rotation of the young massive cluster R136

Hénault-Brunet, V.; Gieles, M.; Evans, C. J.; Sana, H.; Bastian, N.; Maíz Apellániz, J.; Taylor, W. D.; Markova, N.; Bressert, E.; de Koter, A.; van Loon, J. Th.
Astronomy & Astrophysics, Volume 545, id.L1, 5 pp. (2012).


Although it has important ramifications for both the formation of star clusters and their subsequent dynamical evolution, rotation remains a largely unexplored characteristic of young star clusters (few Myr). Using multi-epoch spectroscopic data of the inner regions of 30 Doradus in the Large Magellanic Cloud obtained as part of the VLT-FLAMES Tarantula Survey, we search for rotation of the young massive cluster R136. From the radial velocities of 36 apparently single O-type stars within a projected radius of 10 pc from the centre of the cluster, we find evidence, at the 95% confidence level, for rotation of the cluster as a whole. We use a maximum likelihood method to fit simple rotation curves to our data and find a typical rotational velocity of ~3 km s-1. When compared to the low velocity dispersion of R136, our result suggests that star clusters may form with at least ~20% of the kinetic energy in rotation.

Based on observations collected at the European Southern Observatory under program ID 182.D-0222.