[填空题]
Suppose a star the size of our Sun, but with mass 8ek+0d8(kku4-e 1fk ktspjh *h.0 time3bgakr 28/,fbfw xk :es 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, logbkf:x82e3wk, / afr bsing 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. $\times10^{9 }$ $rev/day$