Bulk viscosity in a hyperonic star and r-mode instability

T. K. Jha, H. Mishra, and V. Sreekanth
Phys. Rev. C 82, 025803 – Published 11 August 2010

Abstract

We consider a rotating neutron star with the presence of hyperons in its core. We use an equation of state in an effective chiral model within the relativistic mean-field approximation. We calculate the hyperonic bulk viscosity coefficient caused by nonleptonic weak interactions. By estimating the damping time scales of the dissipative processes, we investigate its role in the suppression of gravitationally driven instabilities in the r mode. We observe that r-mode instability remains very significant for hyperon core temperatures of around 108K, which results in a comparatively larger instability window. We find that such instability can reduce the angular velocity of the rapidly rotating star considerably up to ~0.04ΩK, with ΩK as the Keplerian angular velocity.

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  • Received 26 February 2010

DOI:https://doi.org/10.1103/PhysRevC.82.025803

©2010 American Physical Society

Authors & Affiliations

T. K. Jha1,2,*, H. Mishra1,†, and V. Sreekanth1,‡

  • 1Theoretical Physics Division, Physical Research Laboratory, Navrangpura, Ahmedabad-380 009, India
  • 2Physics Group, Birla Institute of Technology and Science Pilani, Goa Campus, Goa-403 726, India

  • *tkjha@bits-goa.ac.in
  • hm@prl.res.in
  • skv@prl.res.in

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Vol. 82, Iss. 2 — August 2010

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