Tidal disruption of a solar-type star by a supermassive black hole

We study the long-term evolution of a solar-type star that is being disrupted by a supermassive (10(6) M.) black hole. The evolution is followed from the disruption event, which turns the star into a long, thin stream of gas, to the point at which some of this gas returns to pericenter and begins its second orbit around the black hole. Following the evolution for this long allows us to determine the amount of mass that is accreted by the black hole. We find that approximately 75% of the returning mass is not accreted but instead becomes unbound, following the large compression characterizing the return to pericenter. The impact of a tidal disruption on the surrounding gas may therefore be like that of two consecutive supernova-type events.