Anisotropic convection in rotating protoneutron stars
Abstract
We study the conditions for convective instability in rotating, nonmagnetic protoneutron stars. The criteria that determine stability of nascent neutron stars are analogous to the SolbergHøiland conditions but including the presence of lepton gradients. Our results show that, for standard angular velocity profiles, convectively unstable modes with wavevectors parallel to the rotation axis are suppressed by a stable angular momentum profile, while unstable modes with wavevectors perpendicular to the axis remain unaltered. Since the wavevector 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 protoneutron stars with the only requirement that angular velocities be of the order of the convective characteristic frequency.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 June 2004
 DOI:
 10.1051/00046361:20035924
 arXiv:
 arXiv:astroph/0403021
 Bibcode:
 2004A&A...420..245M
 Keywords:

 stars: neutron;
 stars: rotation;
 stars: supernovae: general;
 hydrodynamics;
 Astrophysics
 EPrint:
 5 pages, 4 figures, final version to appear in A&