Nonradial oscillations of neutron stars: A new branch of strongly damped normal modes

We study small, nonradial oscillations of neutron stars in a general relativistic perturbation treatment, considering different values for the central density of the star. We adapt two techniques used previously for the determination of quasinormal modes of black holes, allowing us for the first time to determine without approximation solutions which satisfy purely outgoing boundary conditions at spatial infinity. We confirm the existence of strongly damped complex normal modes found by Kokkotas and Schutz ($w$ modes). In addition, we identify a new branch of strongly damped modes (${w}_{\mathrm{II}}$ modes). Our new modes are much more similar to quasinormal modes of black holes than the $w$ modes known before.

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