Hannover 2003 – wissenschaftliches Programm

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GR: Gravitation und Relativitätstheorie

GR VII: HV VII

GR VII.1: Hauptvortrag

Donnerstag, 27. März 2003, 14:00–15:00, A310

Gravitational waves from neutron stars with large toroidal B-fields — •Curt Cutler — Max-Planck-Institut für Gravitationsphysik, Am Mühlenberg 1, 14476 Golm

We show that neutron stars (NS’s) with large toroidal B-fields tend naturally to evolve into potent gravitational-wave (gw) emitters. The toroidal field B_t tends to distort the NS into a prolate shape, and this magnetic distortion can easily dominate over the oblateness “frozen into” the NS crust. A NS with frozen-in B-field of this magnitude is secularly unstable: the wobble angle between the NS’s angular momentum and the star’s magnetic axis will grow on a dissipation timescale until they are orthogonal. This final orientation is clearly the optimal one for gw emission. We show that for LMXB’s with B_t of order 10¹³ G, the spindown from gw’s is sufficient to balance the accretion torque–supporting a suggestion by Bildsten. The spindown rates of most millisecond pulsars can also be attributed to gw emission sourced by toroidal B-fields, and both these sources could be observed by LIGO II.