view Abstract Citations (56) References (49) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The equilibrium of a galactic bar Vandervoort, P. O. Abstract It is shown that, for values of the polytropic index not less than 0.5, every uniformly rotating, gaseous polytrope has an exact stellar-dynamical counterpart. Like gaseous polytropes, uniformly rotating polytropic stellar systems have axisymmetric configurations of equilibrium and, provided that the polytropic index is less than 0.808, nonaxisymmetric configurations of equilibrium as well. The axisymmetric and nonaxisymmetric configurations form linear sequences which correspond, respectively, to the Maclaurin and Jacobi sequences of uniformly rotating, homogeneous fluid ellipsoids. The distribution functions in these stellar systems are functions of Jacobi's integral alone; consequently, the systems exhibit no differential motions in their rotating frames of reference, and the distributions of the peculiar velocities of their stars are isotropic. The nonaxisymmetric configurations are counterexamples to the prevailing conjecture that stellar systems can be triaxial only if their distribution functions depend on three isolating integrals of the motion. Publication: The Astrophysical Journal Pub Date: September 1980 DOI: 10.1086/158253 Bibcode: 1980ApJ...240..478V Keywords: Barred Galaxies; Galactic Rotation; Galactic Structure; Polytropic Processes; Star Clusters; Stellar Motions; Stellar Systems; Astronomical Models; Body Kinematics; Elliptical Galaxies; Astrophysics full text sources ADS |