Is collapse of a deformed star always effectual for gravitational radiation?

Abstract

We have computed the energy of gravitational radiation from an axially symmetric, non-rotating dust shell of mass m falling into a Schwarzschild black hole of mass M ⪢ m. Both prolate and oblate dust shells are examined. A strongly deformed dust shell radiates less gravitational waves than a moderately deformed one. The radiation energy from a dust shell is less than that from a test particle, which is contrary to the newtonian result of Thuan and Ostriker which did not take phase cancellation effects into account.