Hypervelocity Collisions of Binary Stars at the Galactic Centre

Abstract

Recent surveys have identified seven hypervelocity stars (HVSs) in the halo of the Milky Way. Most of these stars may have originated from the breakup of binary star systems by the nuclear black hole SgrA*. In some instances, the breakup of the binary may lead to a collision between its member stars. We examine the dynamical properties of these collisions by simulating thousands of different binary orbits around SgrA* with a direct N-body integration code. For some orbital parameters, the two stars collide with an impact velocity lower than their escape velocity and may therefore coalesce. It is possible for a coalescing binary to have sufficient velocity to escape the galaxy. Furthermore, some of the massive S-stars near Sgr A* might be the merger remnants of binary systems, however this production method can not account for most of the S-stars.

5 pages, 2 figures, accepted for publication in MNRAS

References in corpus (5)

• Stellar Multiplicity and the IMF: Most Stars Are Single
• Hypervelocity Stars: Predicting the Spectrum of Ejection Velocities
• Hypervelocity Stars. I. The Spectroscopic Survey
• A Successful Targeted Search for Hypervelocity Stars
• Collisions and close encounters involving massive main-sequence stars

Cited by in corpus (4)

• Hypervelocity Stars: From the Galactic Center to the Halo
• Hypervelocity Stars III. The Space Density and Ejection History of Main Sequence Stars from the Galactic Center
• Ejection of hypervelocity binary stars by a black hole of intermediate mass orbiting Sgr A*
• Hypervelocity A & B Stars should be slow rotators