how to become a self star

Why spin angular velocity of a star is greatly enhanced when it collapses under gravitational pull and becomes a neutron star ?

The two stars in a certain binary star system move in circular orbits The first star alpha moves in an orbit of radius 1.00 xx 10^(9)km The other star beta moves in an orbit of radius 5.00 xx 10^(8)km What is the ratio of masses of star beta to the star alpha ? .