NWO postdoc @ Amsterdam University
A MAD view of Trumpler 14
H. Sana, Y. Momany, M. Gieles, G. Carraro, Y. Beletsky, V.D. Ivanov, G. De Silva, G. James
We present adaptive optics (AO) near-infrared observations of the Tr 14 cluster in the Carina region obtained using the ESO multi-conjugate AO demonstrator, MAD. Our campaign yields AO-corrected observations with an image quality of about 0.2" across the 2' field of view, which is the widest AO campaign towards a young open cluster. We detected about 2000 sources spanning a dynamic range of 10 mag. The pre-main sequence (PMS) locus in the colour-magnitude diagram is well reproduced by Palla & Stahler isochrones with an age of 3 to 5x105 yr, confirming the very young age of the cluster. We derive a very high (deprojected) central density n0~4x104 pc-3 and we estimate the mass in the cluster core to be about 4x103 Msun, although contamination of the field of view might significantly contribute to the mass. We show that the pairing process is largely dominated by chance alignment so that physical pairs are difficult to disentangle from spurious ones based on our single epoch observation. Yet, we identify 150 likely bound pairs, 30% of these with a separation smaller than 0.5". We further show that, at the 2 sigma level, massive stars have more solar-mass companions than solar-mass PMS stars and that those companions are brighter on average, thus more massive. Finally, we find some hints of mass segregation for stars heavier than about 10 Msun. If confirmed, the observed degree of mass segregation could be explained by dynamical evolution, despite the young age of the cluster.
Color-magnitude diagram (CMD)
Companion distribution functions
ESO Press release ; Dowload full paper @ arXiv:1003.2208