[填空题]
Suppose a star the siicf*h7 7sfdzp7e m*)g ze of o ggu10rf 5*r bsqh+m4eur Sun, but with mass 8.0 times as great, were rotating at a speed of 1.0 revolution every 12 days. If it were to undergo gravita+rbs0 e*ug14m5r ghq ftional 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. $\times10^{9 }$ $rev/day$