Motion of Stars in Layered Inhomogeneous Elliptical Galaxies

TL;DR

This paper models the motion of stars within layered inhomogeneous elliptical galaxies considering both baryonic and dark matter influences, providing exact potential calculations and stability analysis of star trajectories.

Contribution

It introduces a precise method for analyzing star motion in elliptical galaxies with layered density profiles, including exact potential expressions and stability of libration points.

Findings

Stable Lyapunov libration points identified.

Exact gravitational potentials used without series expansion.

Applied model to specific elliptical galaxies.

Abstract

The problem of the spatial motion of a passively gravitating body (PGB) in the gravitational field of a layered inhomogeneous elliptical galaxy (LIEG) is considered on the basis of the previously developed model. It is assumed that a LIEG consists of baryonic mass (BM) and dark matter (DM), which have different laws of density distribution. A star or the center of mass of a globular cluster is taken as the PGB, the motion of which considers the BM and DM attraction. To obtain accurate results, the BM and DM attraction potentials are not expanded in a series, but their exact expressions are taken. An analogue of the Jacobi integral is found, the region of the possible motion of the PGB is determined, and the zero-velocity surfaces are constructed. The stationary solutions (libration points) are found to be stable in the sense of Lyapunov. The results are applied to the elliptical galaxies NGC 4472 (M 49), NGC 4697, and NGC 4374 (M 84).