[填空题]
Suppose a star the size of our Sun, but with m ; l8/che:b1br 34hgamn dzmpjd5zn,-ass 8./h; ,gb;k zbwn)/ oydt0 times as great, were rotating a ),/ bbt/;ghy odwn;zkt a speed of 1.0 revolution every 12 days. If it were to undergo gravitational collapse to a neutron star of radius 11 km, losing three-quarters of its mass in the process, what would its rotation speed be? Assume that the star is a uniform sphere at all times, and that the lost mass carries off no angular momentum. $\times10^{9 }$ $rev/day$