The cores of compact stars reach the highest densities in nature and therefore could consist of novel phases of matter. They can be probed seismologically via mechanical oscillation modes. One example is unstable r-modes which, if not efficiently damped, emit gravitational waves that would quickly spin down a millisecond pulsar. The damping is determined by microscopic properties of the dense interior. We demonstrate via a detailed analysis of the pulsar evolution how precise pulsar timing data can constrain the star’s composition. We find that interacting quark matter is consistent with both the observed radio and x-ray data, whereas for ordinary nuclear matter some additional enhanced damping mechanism will be required.
Date added: Tue, 15 Oct 13