  Was PS1-10jh (Gezari et al. 2012), an optical/UV transient discovered by the
Pan-STARRS Medium Deep Survey, the tidal disruption of a star by a massive
black hole? We address two aspects of the problem: the composition of the
putative disrupted object (using the spectroscopic data), and the energetics of
the observed gas and radiation (using the photometric data). We perform
photoionization calculations and compare with the observed lower limit of the
line ratio L(He II 4686)/L(Halpha) > 5 to argue that this event was not the
disruption of a solar-type star, and instead was likely the disruption of a
helium core (as first proposed by Gezari et al. 2012). Disruption of such a
dense object requires a relatively small central BH, M_BH <~ 2 x 10^5 M_sun. We
use the photometric data to infer that PS1-10jh comprised an outflow of ~ 0.01
M_sun of gas, escaping from the BH at ~1000 km/s, and we propose that this
outflow was driven primarily by radiation pressure trapped by Thomson and
resonance line scattering. The large ratio of radiated energy to kinetic
energy, E_rad/E_K ~ 10^4, together with the large value of E_rad ~ 2 x 10^(51)
erg, suggests that the outflow was shocked at large radius (perhaps similar to
super-luminous supernovae or the internal shock model for gamma-ray bursts). We
describe puzzles in the physics of PS1-10jh, and discuss how this event may
help us understand future tidal disruptions and super-Eddington accretion
events as well.
