Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2011-10-31
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
11 pages. MNRAS submitted
Scientific paper
It is theoretically expected that a supermassive black hole (SMBH) in the centre of a typical nearby galaxy disrupts a Solar-type star every ~ 10^5 years, resulting in a bright flare lasting for months. Sgr A*, the resident SMBH of the Milky Way, produces (by comparison) tiny flares that last only hours but occur daily. Here we explore the possibility that these flares could be produced by disruption of smaller bodies - asteroids. We show that asteroids passing within an AU of Sgr A* could be split into smaller fragments which then vaporise by bodily friction with the tenuous quiescent gas accretion flow onto Sgr A*. The ensuing shocks and plasma instabilities may create a transient population of very hot electrons invoked in several currently popular models for Sgr A* flares, thus producing the required spectra. We estimate that asteroids larger than ~ 10 km in size are needed to power the observed flares, with the maximum possible luminosity of the order 10^39 erg s^-1. Assuming that the asteroid population per parent star in the central parsec of the Milky Way is not too dissimilar from that around stars in the Solar neighbourhood, we estimate the asteroid disruption rates, and the distribution of the expected luminosities, finding a reasonable agreement with the observations. We also note that planets may be tidally disrupted by Sgr A* as well, also very infrequently. We speculate that one such disruption may explain the putative increase in Sgr A* luminosity ~ 300 yr ago.
Markoff Sera
Nayakshin Sergei
Zubovas Kastytis
No associations
LandOfFree
Sgr A* flares: tidal disruption of asteroids and planets? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Sgr A* flares: tidal disruption of asteroids and planets?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sgr A* flares: tidal disruption of asteroids and planets? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-148212