[math-fun] Black Hole Binaries can eject relativistic normal stars
FYI -- Apparently, just like planets & planetoids can be ejected from solar systems, regular stars can be ejected from a system of binary black holes. I presume that "living" in a planetary system of such a star would provide time dilation relative to the rest of the universe. Of course, the event which accelerated the star in the first place might a) strip the star of all/most of its planets; or at least b) kill all life on any such planets that do manage to escape with the star. http://arxiv.org/abs/1411.5030 Observational Cosmology With Semi-Relativistic Stars Abraham Loeb (1), James Guillochon (1) ((1) Harvard ITC) (Submitted on 18 Nov 2014) "Galaxy mergers lead to the formation of massive black hole binaries which can accelerate background stars close to the speed of light. We estimate the comoving density of ejected stars with a peculiar velocity in excess of $0.1c$ or $0.5c$ to be $\sim 10^{10}$ and $10^5$ Gpc$^{-3}$ respectively, in the present-day Universe. Semi-relativistic giant stars will be detectable with forthcoming telescopes out to a distance of a few Mpc, where their proper motion, radial velocity, and age, can be spectroscopically measured. In difference from traditional cosmological messengers, such as photons, neutrinos, or cosmic-rays, these stars shine and so their trajectories need not be directed at the observer for them to be detected. Tracing the stars to their parent galaxies as a function of speed and age will provide a novel test of the equivalence principle and the standard cosmological parameters. Semi-relativistic stars could also flag black hole binaries as gravitational wave sources for the future eLISA observatory." "In the context of astro-biology, SHS could spread life beyond the boundaries of their host galaxies [26, 27]."
Frederic Pohl's book _The World at the End of Time_ includes this as a major plot point. On Mon, Dec 1, 2014 at 11:43 AM, Henry Baker <hbaker1@pipeline.com> wrote:
FYI -- Apparently, just like planets & planetoids can be ejected from solar systems, regular stars can be ejected from a system of binary black holes.
I presume that "living" in a planetary system of such a star would provide time dilation relative to the rest of the universe. Of course, the event which accelerated the star in the first place might a) strip the star of all/most of its planets; or at least b) kill all life on any such planets that do manage to escape with the star.
http://arxiv.org/abs/1411.5030
Observational Cosmology With Semi-Relativistic Stars
Abraham Loeb (1), James Guillochon (1) ((1) Harvard ITC) (Submitted on 18 Nov 2014)
"Galaxy mergers lead to the formation of massive black hole binaries which can accelerate background stars close to the speed of light. We estimate the comoving density of ejected stars with a peculiar velocity in excess of $0.1c$ or $0.5c$ to be $\sim 10^{10}$ and $10^5$ Gpc$^{-3}$ respectively, in the present-day Universe. Semi-relativistic giant stars will be detectable with forthcoming telescopes out to a distance of a few Mpc, where their proper motion, radial velocity, and age, can be spectroscopically measured. In difference from traditional cosmological messengers, such as photons, neutrinos, or cosmic-rays, these stars shine and so their trajectories need not be directed at the observer for them to be detected. Tracing the stars to their parent galaxies as a function of speed and age will provide a novel test of the equivalence principle and the standard cosmological parameters. Semi-relativistic stars could also flag black hole binaries as gravitational wave sources for the future eLISA observatory."
"In the context of astro-biology, SHS could spread life beyond the boundaries of their host galaxies [26, 27]."
_______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
-- Mike Stay - metaweta@gmail.com http://www.cs.auckland.ac.nz/~mike http://reperiendi.wordpress.com
participants (2)
-
Henry Baker -
Mike Stay