The Ejection of Low Mass Clumps During Star Formation

TL;DR

This paper models how low mass clumps form and can be ejected during star formation, potentially explaining the origin of free-floating low mass stars, brown dwarfs, and planets.

Contribution

It introduces a detailed model of clump ejection during star formation, highlighting a new pathway for forming low mass objects.

Findings

Clumps originate as Larson first cores and grow by accretion.

Gravitational scattering can eject low mass clumps from disks.

Ejected clumps may become free-floating stars or planets.

Abstract

Modeling of the self-consistent formation and evolution of disks as a result of prestellar core collapse reveals an intense early phase of recurrent gravitational instability and clump formation. These clumps generally migrate inward due to gravitational interaction with trailing spiral arms, and can be absorbed into the central object. However, in situations of multiple clump formation, gravitational scattering of clumps can result in the ejection of a low mass clump. These clumps can then give rise to free-floating low mass stars, brown dwarfs, or even giant planets. Detailed modeling of this process in the context of present-day star formation reveals that these clumps start out essentially as Larson first cores and grow subsequently by accretion. In the context of Pop III star formation, preliminary indications are that the disk clumps may also be of low mass. This mechanism of clump formation and possible ejection provides a channel for the formation of low mass objects in the first generation of stars.