TIDAL DISRUPTION OF STARS BY THE BLACK HOLE SGR A*

J. Rocha & M.Avillez

Tidal Disruption Events (TDES) of a solar type star by the super massive black hole (SMBH) Sgr A*, with 4.6 million solar masses, and located near the Galactic Center. When a star is gravitationally captured by the black hole it enters in a fatal orbit onto the compact object. Such orbits are characterized by the penetration parameter (b) which determines how deep the star penetrates into the tidal radius (Rt; the limit for a star to be tidally disrupted) of the SMBH and its eccentricity (ecc). Stars can approach the black hole in two different orbits: parabolic and elliptic, which can be differentiated by the eccentricity of the trajectory of the star, respectively, in a parabolic orbit the star describes a trajectory with ecc=1 and in an elliptic orbit 0<ecc<1. With increasing b the star attains shorter distances at the pericenter Rp, the closest distance of its orbit to the black hole, and suffers the effects of the gravitational tidal forces induced by the compact object. When the stars experiences tidal deformations it develops two tidal tails and is continuously stretched, where the envelope mass is depletted from its surface during the “pancake phase”. In the Figure the upper panel shows a TDE of star on a parabolic orbit and in the bottom panel it shows the TDE of a star on an elliptic orbit, in both cases the star crosses Rt with b=5.