[填空题]
Suppose a star the size of our Sun, but with mao: y-nqyne; *kss 8.0 bya1no;:qxc0times 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 axc:0ony; ba 1qll times, and that the lost mass carries off no angular momentum. $\times10^{9 }$ $rev/day$