Viscous damping of r-modes: Large amplitude saturation

Alford M. G., Mahmoodifar S., Schwenzer K. O.

PHYSICAL REVIEW D, cilt.85, sa.4, 2012 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 85 Sayı: 4
  • Basım Tarihi: 2012
  • Doi Numarası: 10.1103/physrevd.85.044051
  • Dergi Adı: PHYSICAL REVIEW D
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • İstanbul Üniversitesi Adresli: Hayır

Özet

We analyze the viscous damping of r-mode oscillations of compact stars, taking into account nonlinear viscous effects in the large-amplitude regime. The qualitatively different cases of hadronic stars, strange quark stars, and hybrid stars are studied. We calculate the viscous damping times of r-modes, obtaining numerical results and also general approximate analytic expressions that explicitly exhibit the dependence on the parameters that are relevant for a future spin-down evolution calculation. The strongly enhanced damping of large-amplitude oscillations leads to damping times that are considerably lower than those obtained when the amplitude dependence of the viscosity is neglected. Consequently, large-amplitude viscous damping competes with the gravitational instability at all physical frequencies and could stop the r-mode growth in case this is not done before by nonlinear hydrodynamic mechanisms.