Incompressible fluid ellipsoids in halos. I. The second-harmonic oscillations of the Maclaurin spheroids
Journal Article
·
· Astrophys. J.; (United States)
The structure and stability of Maclaurin spheroids embedded in rigid, uniform-density, oblate spheroidal halso are determined by the tensor virial equation method. These spheroid-halos are assumed to have the same center, the same axis of symmetry, and the same equatorial radius as the Maclaurin spheroids. Only halos with lower eccentricity than the Maclaurin spheroids are considered.The dynamic instability of the toroidal (barlike) modes is suppressed when m, the ratio of the halo mass to Maclaurin spheroid mass, is greater than 3..pi../8 for spherical halos and when m>1/2 for halos congruent to the Maclaurin spheroids. Intermediate halo flattenings yield intermediate critical m-values. On the other hand, a neutral point of the toroidal modes in the rotating and inertial frames occurs for all m and for all allowed halo flattenings. Growth rates second-harmonic modes are given for select cases. Attmepts to find simple, general parameters to characterize the secular and dynamic instability points prove unsuccessful. The Ostriker-Peebles conjecture concerning the stability of disk galaxies against barlike perturbations appears to be incorrect.
- Research Organization:
- Theoretical and Planetary Studies Branch, Space Science Division, NASA Ames Research Center, Moffett Field, CA
- OSTI ID:
- 6617873
- Journal Information:
- Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 224:3; ISSN ASJOA
- Country of Publication:
- United States
- Language:
- English
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