Dynamics and origins of the young stars in the Galactic center

Abstract

The environment near the massive black hole (MBH) in the Galactic center is very hostile for star formation. Nevertheless, many young stars (both O and B stars) are observed close the MBH. The B-stars seems to have an isotropic, continuous distribution between 0.01 pc and up to a pc. The O (and Wolf-Rayet;WR) stars, in contrast, seem to be distributed in a coherent disk like configuration, extending only between ~0.04 pc to ~0.5 pc. Our current understanding favors an in-situ formation origin for the more massive (O and WR) stars, in gaseous disk and/or streams from an in-falling gas clump. The B-stars seem to have a different origin, more likely through a dynamical capture, following a binary disruption by the MBH. This scenario could also be able to explain the origin of hypervelocity stars in the Galactic halo. These and other possible origins of the young stars in the Galactic center are briefly reviewed and their possible observational signatures and constraints are detailed.