Astronomy and Astrophysics – Astrophysics
Scientific paper
Dec 2009
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009aas...21360110h&link_type=abstract
American Astronomical Society, AAS Meeting #213, #601.10
Astronomy and Astrophysics
Astrophysics
Scientific paper
We investigate nonaxisymmetric instabilities of self-gravitating polytropic tori. The large number of observed extra-solar planetary and protostellar systems has sparked extensive interest in modeling astrophysical disks. An important parameter of these systems is the star to disk mass ratio. We investigate the limiting case where the star mass equals zero - all the mass of the system is contained in the disk. These are obviously systems where self-gravity plays an important evolutionary role, spawning I and J modes. We consider models with power law angular velocity distributions with rotation indices of q = [1,2] and polytropic index 1.5, and consider modes with azimuthal dependence exp(ima) where m is the azimuthal mode number and a is the azimuthal angle. We find that threshold stability for I modes lies at about T/|W| = 0.16 where T is rotational kinetic energy and W is gravitational potential energy. Growth rates increase to about (0.3 - 0.4) tm-1, then decrease to stable models at about T/|W| = 0.25, regardless of q. Here, tm is the rotation period of the equilibrium toroid at the density maximum. For higher T/|W|, the J mode growth rates overtake the I modes and increase monotonically. Oscillation frequencies decrease to a minimum around T/|W| = 0.2 and then increase monotonically. We compare linear models with fully nonlinear models for a few cases, and show that J modes with m > 2 dominate for higher T/|W|.
Hadley Kathy
Imamura James N.
No associations
LandOfFree
Nonaxisymmetric Instabilities of Self-gravitating Toroids does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Nonaxisymmetric Instabilities of Self-gravitating Toroids, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nonaxisymmetric Instabilities of Self-gravitating Toroids will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1765481