Astro-seminar , Wednesday , 09Nov2011 at 14:00 in Holcblat.

Speaker: Yanir Hainick, TAU
Title: Love Triangles in Space - Hypervelocity Stars on Eccentric Orbits

Abstract:
Hypervelocity stars are stars with velocities exceeding the escape velocity of the Galaxy, 16 of which are known today observationally. One of the most popular models for their creation involves a 3-body interaction between a binary star and the Supermassive black hole in the center of the Galaxy, which causes tidal break-up of the binary star. These kind of interactions are often accompanied with an energy exchange, where one of the binary members gains energy (and therefore - velocity) and gets ejected from the system, while the other member losses energy and becomes bound to the Black Hole. We will review the problem of a binary star approaching the Black Hole in an eccentric orbit, estimate roughly the minimum eccentricity for ejections to occur, and examine typical ejection energies.