[填空题]
Suppose a star the size of our-b8 dze,4hma(pfpv w/ Sun, but with m5*e c0rcw)+ cfa 5suxdass 8.0 times as great, were rotating at a spa0w5c+rd 5x f)ce* suceed 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. $\times10^{9 }$ $rev/day$