http://arxiv.org/abs/1707.03421
Approximately once every $10^4$ years, a star passes close enough to the supermassive black hole Sgr A* at the center of the Milky Way to be pulled apart by the black hole’s tidal forces. The star is then “spaghettified” into a long stream of matter, with approximately one half being bound to Sgr A* and the other half unbound. Within this stream, the local self-gravity dominates the tidal field of Sgr A*, which at minimum restricts the stream to a small finite width. As the stream cools from adiabatic expansion and begins to recombine, the residual self-gravity allows for planetary-mass fragments to form along the length of the stream; these fragments are then shot out into the galaxy at range of velocities, with the fastest moving at ~10% c. We determine the phase space distributions of these fragments for a realistic ensemble of stellar disruptions, along with the local density of fragments in the solar neighborhood. We find that ~$10^7$ fragments produced by Sgr A* accumulate within the Milky Way over its lifetime, that there are ~$10^7$ fragments that lie within 1 Mpc of the Milky Way originating from other galaxies, and that the nearest fragment to our Sun is on average 500 pc distant.
E. Girma and J. Guillochon
Thu, 13 Jul 17
47/60
Comments: 6 pages, 5 figures. Submitted to ApJL
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