EDP Sciences
Free access
Volume 410, Number 3, November II 2003
Page(s) 975 - 981
Section Stellar atmospheres
DOI http://dx.doi.org/10.1051/0004-6361:20031320

A&A 410, 975-981 (2003)
DOI: 10.1051/0004-6361:20031320

Hydromagnetic stability of differentially rotating neutron stars

V. Urpin

A. F. Ioffe Institute for Physics and Technology, SU 194021, St. Petersburg, Russia

Isaak Newton Institute of Chili, Branch in St. Petersburg, Russia
(Received 31 March 2003 / Accepted 21 August 2003)

The stability properties of differentially rotating magnetic neutron stars are considered, and the instability criteria are obtained. The influence of the magnetic field is twofold: it may stabilize a fluid against some instabilities, on the one hand, and it can lead to new branches of instabilities, on the other hand. It turns out that some of the instability criteria of magnetic neutron stars can be satisfied at smaller departures from the uniform rotation than the criteria of non-magnetic stars. Interaction of hydrodynamic motions caused by instabilities in the core with the neutron star crust can result in small irregularities in the measured spin period of pulsars.

Key words: magnetohydrodynamics (MHD) -- stars: neutron -- stars: rotation -- stars: pulsars: general

© ESO 2003