2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/213893We discuss bulk viscosity due to non-leptonic processes involving hyperons and Bose-Einstein condensate of negatively charged kaons in neutron stars. It is noted that the hyperon bulk viscosity coefficient is a few order of magnitude larger than that of the case with the condensate. Further it is found that the hyperon bulk viscosity is suppressed in a superconducting phase. The hyperon bulk viscosity efficiently damps the r-mode instability in neutron stars irrespective of whether a superconducting phase is present or not in neutron star interior.5 pages, 4 figues; to be published in the proceedings of the 10th International Symposium on Nuclei in the Cosmos, 27 July - 1 August, 2008, Mackinac Island, Michigan, USAAstrophysicstext