[填空题]
Suppose a star the size:a zy2 oexue*4 of our Sun, but wites hlsm1*3q;ch mass 8.0 times as great, were rotating at 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 thqcm*;l3s e s1he lost mass carries off no angular momentum. $\times10^{9 }$ $rev/day$