Hydrodynamic Model Calculations for Supermassive Stars I. The Collapse of a Nonrotating 0.75 X 106 M0 Star

Th order to test Fowler's models for QSOs and exploding galaxies we calculated the pre-main-sequence contraction and the relativistic dynamical collapse of a nonrotating 0.75 x 100 Me supermassive star by solving numerically the (relativistic) hydiodynamic equations. In contrast to earlier estimates we found that in such a star the rapid burning of hydrogen cannot halt the collapse before the Schwarzschild radius is reached. Thus, a nourotating 0.75 x 108 Me star will not undergo relaxation oscillations but will end up as a supermassive black hole after a rather short life time of some 102 years. Key words: supermassive stars - QSOs - gravitational collapse