Preferred orbit planes in the gravitational field of a tumbling spheroidal galaxy

Journal Article · Sat Jan 15 04:00:00 EST 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160606· OSTI ID:5910153

Durisen, R H; Tohline, J E; Burns, J A; Dobrovolskis, A R

The orientation and kinematics of gas disks may provide clues concerning the true three-dimensional shapes of elliptical galaxies. This paper describes a simple, analytic method for determining the preferred planes into which gas will settle by dissipative differential precession in a slightly nonspherical, nonstatic potential. In particular, we thoroughly analyze precession of circular orbits in the external potential of a slightly prolate spheroidal mass that is tumbling about a short axis. This provides a crude model for barred spiral galaxies as well as for prolate elliptical galaxies. For small radial distances from the center, the preferred planes correspond to orbits in the equatorial plane of the spheroid; at large radial distances, they correspond to orbits in the principal plane perpendicular to the tumble axis. Inner and outer gas disks can thus be orthogonal to one another, as is occasionally observed in real galaxies. The transition with radius between these preferred orbital orientations is mapped out in detail and is found to be smooth for gas in orbits that are retrograde with respect to the tumble direction. Our results agree with work by others on the existwence, orientation, and stability of periodic orbits in triaxial potentials. Simple physical interpretations of our analytic solutions are provided. Depending on the source and injection geometry of the gas and on the nature of dissipation in the gas, the orbital dynamics could lead to enhanced, or even catastrophic, radial inflow and to steady-state warped structures.

• OSTI ID: 5910153
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 264:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANALYTICAL SOLUTION
CLASSICAL MECHANICS
COSMIC GASES
ENERGY LOSSES
FLUIDS
FUNCTIONS
GALAXIES
GASES
GRAVITATIONAL FIELDS
HAMILTONIAN FUNCTION
LOSSES
MECHANICS
MORPHOLOGY
ORBITS
PRECESSION
SPHEROIDS