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“Young Stars in the Galactic Center” Dr. Alessia Gualandris Max-Planck Institute for Astrophysics |
| Near-infrared imaging and spectroscopy of the Galactic center indicate the presence of over 100 young massive stars in the inner parsec of the Milky Way. These belong to two distinct populations: (1) Outside the central arcsecond, a group of roughly 40 stars, mostly O and Wolf-Rayet stars with an estimated age of 6Myr, move on approximately circular orbits in a thin and coherent stellar disk. (2) Inside the central arcsecond, a group of 20 B-type stars (the S-stars) move on eccentric and randomly oriented orbits around the supermassive black hole (SMBH). The existence of young massive stars so close to the SMBH is puzzling since tidal stresses from the SMBH are likely to suppress star formation in this region. If the S-stars formed at larger distances from SgrA* and were then transported inward, the migration would need to occur on a timescale of only a few Myr, given the apparent age of the stars. This constitutes the so-called paradox of youth. I will discuss different models for the origin of the young stars in the Galactic center and present recent results obtained by means of state-of-art numerical simulations. I will also discuss the short and long term effects of an intermediate-mass black hole on the orbits of the stars bound to the SMBH. |