r-mode oscillations in rotating magnetic neutron stars

Luciano Rezzolla, Frederick K. Lamb, Stuart L. Shapiro

Research output: Contribution to journalArticlepeer-review

Abstract

We show that r-mode oscillations distort the magnetic fields of neutron stars and that their occurrence is likely to be limited by this interaction. If the field is ≥ 1016(Ω/ΩΒ) G, where Ω and ΩΒ are the angular velocities of the star and at which mass shedding occurs, r-mode oscillations cannot occur. Much weaker fields will prevent gravitational radiation from exciting r-mode oscillations or will damp them on a relatively short timescale by extracting energy from the modes faster than gravitational-wave emission can pump energy into them. For example, a 1010 G poloidal magnetic field that threads the star's superconducting core is likely to prevent the l = 2 mode from being excited unless Ω exceeds 0.35ΩΒ. If Ω is larger than 0.35ΩΒ initially, the l = 2 mode may be excited but is likely to decay rapidly once Ω falls below 0.35ΩΒ, which happens in ≤15 days if the saturation amplitude is ≥0.1. The r-mode oscillations may play an important role in determining the structure of neutron star magnetic fields.

Original languageEnglish (US)
Pages (from-to)L139-L142
JournalAstrophysical Journal
Volume531
Issue number2 PART 2
DOIs
StatePublished - Mar 10 2000

Keywords

  • Instabilities
  • Magnetic fields
  • Stars: Neutron
  • Stars: Oscillations
  • Stars: Rotation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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