Exotic bulk viscosity and its influence on neutron star r-modes

Abstract

We investigate the effect of exotic matter in particular, hyperon matter on neutron star properties such as equation of state (EoS), mass-radius relationship and bulk viscosity. Here we construct equations of state within the framework of a relativistic field theoretical model. As hyperons are produced abundantly in dense matter, hyperon-hyperon interaction becomes important and is included in this model. Hyperon-hyperon interaction gives rise to a softer EoS which results in a smaller maximum mass neutron star compared with the case without the interaction. Next we compute the coefficient of bulk viscosity and the corresponding damping time scale due to the non-leptonic weak process including $\Lambda$ hyperons. Further, we investigate the role of the bulk viscosity on gravitational radiation driven r-mode instability in a neutron star of given mass and temperature and find that the instability is effectively suppressed.

5 pages, 3 figure, presented in the Conference on Isolated Neutron Stars: From the Interior to The Surface, London, UK, 24-28 April, 2006; revised and final version to appear in Astrophys. Space Sci

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Cited by in corpus (6)

• Strangeness-changing Rates and Hyperonic Bulk Viscosity in Neutron Star Mergers
• Bulk viscosity of superfluid hyperon stars
• Hyperon bulk viscosity in strong magnetic fields
• Hyperon bulk viscosity in the presence of antikaon condensate
• Signatures of strangeness in neutron star merger remnants
• Bulk viscosity and r-modes of neutron stars