EDP Sciences
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Volume 420, Number 1, June II 2004
Page(s) 245 - 249
Section Stellar structure and evolution
DOI http://dx.doi.org/10.1051/0004-6361:20035924

A&A 420, 245-249 (2004)
DOI: 10.1051/0004-6361:20035924

Anisotropic convection in rotating proto-neutron stars

J. A. Miralles1, J. A. Pons1 and V.  Urpin1, 2

1  Departament de Física Aplicada, Universitat d'Alacant, Ap. Correus 99, 03080 Alacant, Spain
2  A. F. Ioffe Institute of Physics and Technology and Isaak Newton Institute of Chili, Branch in St. Petersburg, 194021 St. Petersburg, Russia

(Received 11 December 2003 / Accepted 17 February 2004)

We study the conditions for convective instability in rotating, non-magnetic proto-neutron stars. The criteria that determine stability of nascent neutron stars are analogous to the Solberg-Høiland conditions but including the presence of lepton gradients. Our results show that, for standard angular velocity profiles, convectively unstable modes with wave-vectors parallel to the rotation axis are suppressed by a stable angular momentum profile, while unstable modes with wave-vectors perpendicular to the axis remain unaltered. Since the wave-vector is perpendicular to the velocity perturbation, the directional selection of the unstable modes may result in fluid motions along the direction of the rotation axis. This occurs in rigidly rotating stars as well as in the inner core of differentially rotating stars. Our results provide a natural source of asymmetry for proto-neutron stars with the only requirement that angular velocities be of the order of the convective characteristic frequency.

Key words: stars: neutron -- stars: rotation -- stars: supernovae: general -- hydrodynamics

Offprint request: J. A. Pons, Jose.A.Pons@uv.es

© ESO 2004