[填空题]
Suppose a star the sayxu vcq7 88;h,o,q jlize4vx.rp- nge-v of our Sun, but with mass 8.0 times as great, were rotating at a speede n-pr4-v .vxg 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. $\times10^{9 }$ $rev/day$