Self-gravitating fragmentation of eccentric accretion disks

TL;DR

This study investigates how eccentricity influences the fragmentation of gravitationally unstable accretion disks, revealing that eccentricity affects accretion processes and the resulting stellar mass distribution, with implications for star formation near galactic centers.

Contribution

It demonstrates that eccentricity alters accretion dynamics and the stellar mass function in disk fragmentation, providing new insights into star formation mechanisms in eccentric disks.

Findings

Eccentricity does not change overall disk stability against fragmentation.

Eccentricity slows gas accretion and suppresses weakly-bound clump formation.

Fragmentation in eccentric disks results in a higher characteristic stellar mass.

Abstract

We consider the effects of eccentricity on the fragmentation of gravitationally unstable accretion disks, using numerical hydrodynamics. We find that eccentricity does not affect the overall stability of the disk against fragmentation, but significantly alters the manner in which such fragments accrete gas. Variable tidal forces around an eccentric orbit slow the accretion process, and suppress the formation of weakly-bound clumps. The "stellar" mass function resulting from the fragmentation of an eccentric disk is found to have a significantly higher characteristic mass than that from a corresponding circular disk. We discuss our results in terms of the disk(s) of massive stars at ~0.1pc from the Galactic Center, and find that the fragmentation of an eccentric accretion disk, due to gravitational instability, is a viable mechanism for the formation of these systems.