The Fastest Unbound Stars in the Universe · HackerPapers discussions

The Fastest Unbound Stars in the Universe — mentioned by mirimir

Fri, 10 Apr 2015 03:50:43 GMT

The discovery of hypervelocity stars (HVS) leaving our galaxy with speeds of nearly $10^{3}$ km s$^{-1}$ has provided strong evidence towards the existence of a massive compact object at the galaxy's center. HVS ejected via the disruption of stellar binaries can occasionally yield a star with $v_{\infty} \lesssim 10^4$ km s$^{-1}$, here we show that this mechanism can be extended to massive black hole (MBH) mergers, where the secondary star is replaced by a MBH with mass $M_2 \gtrsim 10^5 M_{\odot}$. We find that stars that are originally bound to the secondary MBH are frequently ejected with…

Paper and discussion history. A mention is not an endorsement.

The Fastest Unbound Stars in the Universe — mentioned by throwaway_yy2Di

Sat, 29 Nov 2014 04:17:19 GMT

The point isn't the absolute amount of mass, but how deep the gravitational wells go -- how rapidly objects can orbit. It's not only about massive objects; it's about compact ones. If you have only one supermassive black hole, then the 2nd and 3rd objects are a binary star, and the interaction between them is very weak. Stars can't orbit each other faster than ~100's of km/s (~1,000's for white dwarfs): they're limited by their low density -- they can't get very close or they'll collide. If, instead, you have a star orbiting a black hole -- that's a very dense object, it allows much closer…

Paper and discussion history. A mention is not an endorsement.

The Fastest Unbound Stars in the Universe — mentioned by throwaway_yy2Di

Sat, 29 Nov 2014 03:27:55 GMT

"For the special case of the ejection of binary stars, described in Section 6, we employ octuple floating-point precision (~64 digits)." http://arxiv.org/abs/1411.5022

Paper and discussion history. A mention is not an endorsement.