[填空题]
Suppose a star the size of our Sun, b-wy2wr r-sa4p0ec z2ko e2 8x7;r3nz.glglllut with mass 8.0 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 its mass in the process, what would its rotation speed be? Assume that the star is a unifl ezoc rekggx202ll .l378;znorm sphere at all times, and that the lost mass carries off no angular momentum. $\times10^{9 }$ $rev/day$