r-mode oscillations in rotating magnetic neutron stars

Citation
L. Rezzolla et al., r-mode oscillations in rotating magnetic neutron stars, ASTROPHYS J, 531(2), 2000, pp. L139-L142
Citations number
27
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004-637X → ACNP
Volume
531
Issue
2
Year of publication
2000
Part
2
Pages
L139 - L142
Database
ISI
SICI code
0004-637X(20000310)531:2<L139:ROIRMN>2.0.ZU;2-8
Abstract
We show that r-mode oscillations distort the magnetic fields of neutron sta rs and that their occurrence is likely to be limited by this interaction. I f the field is greater than or equal to 10(16)(Omega/Omega(B)) G, where Ome ga and Omega(B) are the angular velocities of the star and at which mass sh edding occurs, r-mode oscillations cannot occur. Much weaker fields will pr event gravitational radiation from exciting r-mode oscillations or will dam p them on a relatively short timescale by extracting energy from the modes faster than gravitational-wave emission can pump energy into them. For exam ple, a 10(10) G poloidal magnetic field that threads the star's superconduc ting core is likely to prevent the l = 2 mode from being excited unless Ome ga exceeds 0.35 Omega(B). If Omega is larger than 0.35 Omega(B) initially, the l = 2 mode may be excited but is likely to decay rapidly once Omega fal ls below 0.35 Omega(B), which happens in less than or similar to 15 days if the saturation amplitude is greater than or similar to 0.1. The r-mode osc illations may play an important role in determining the structure of neutro n star magnetic fields.