* Astronomy

Title: A new rare type of supernovae: hypervelocity stellar collisions at galactic centers
Authors: Shmuel Balberg (1), Re'em Sari (1), Abraham Loeb (2) ((1) Hebrew University,(2) Harvard ITC)

When a binary star system is tidally disrupted by a supermassive black hole at a galactic nucleus, one star is ejected at a high speed while the other remains in a tightly bound orbit around the black hole. The population of tightly bound stars that builds over time, leads to collisions of stars with one another at a rate which is comparable to capture rate of new stars into this population. A large fraction of these collisions generates an explosive disruption of the two stars involved. The typical explosive flare brightens for several days, with a peak luminosity that is comparable to the lower-luminosity end of known supernovae. The explosion lightcurve is followed by a longer flare due to the accretion of ejected matter onto the black hole. Dedicated searches in the near universe could observe several such "collisional-supernovae" per year.

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