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Abstract

A new family of outgoing-wave normal modes of pulsating relativistic stars which have no Newtonian analogues is demonstrated. These modes, named w-modes, are primarily oscillations of the space-time metric in which the fluid hardly vibrates at all. They are characterized by complex frequencies with unusually large imaginary parts, comparable to their real parts. A sequence of l = 2 modes is calculated for a number of spherical polytropic stellar models. The lowest order mode of each sequence has a frequency similar to that of a spherical black hole. For higher modes, the spectrum diverges from the black-hole spectrum, but shows remarkable similarity to that of the strongly damped modes of the toy problem. These modes are considered to be important and observable in the burst of gravitational radiation that follows the formation of a neutron star.