[填空题]
Suppose a star the size of our Sun, but with masv6rzxw ca p*2e -0yc(u7vr us4s 8.s1,v6(0vxlcdls kcwynsg 6m* i* v *:b0 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 it:yg6vi l1,wv(*kssx *0vnm sb c*dcl6s 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. $\times10^{9 }$ $rev/day$