Stirred, not shaken: star cluster survival in the slingshot scenario

Abstract

We investigate the effects of an oscillating gas filament on the dynamics of its embedded stellar clusters. Motivated by recent observational constraints, we model the host gas filament as a cylindrically symmetrical potential, and the star cluster as a Plummer sphere. In the model, the motion of the filament will produce star ejections from the cluster, leaving star cluster remnants that can be classified into four categories: a) Filament Associated clusters, which retain most of their particles (stars) inside the cluster and inside the filament; b) destroyed clusters, where almost no stars are left inside the filament, and there is no surviving bound cluster; c) ejected clusters, that leave almost no particles in the filament, since the cluster leaves the gas filament; and d) transition clusters, corresponding to those clusters that remain in the filament, but that lose a significant fraction of particles due to ejections induced by filament oscillation. Our numerical investigation predicts that the Orion Nebula Cluster is in the process of being ejected, after which it will most likely disperse into the field. This scenario is consistent with observations which indicate that the Orion Nebula Cluster is expanding, and somewhat displaced from the Integral Shaped Filament ridgeline.

The 3D Kinematics of the Orion Nebula Cluster. II. Mass-dependent Kinematics of the Inner Cluster

“…The observed expansion of the ONC (Kounkel et al 2022) and the supervirial velocity dispersion can be explained by the slingshot mechanism as well according to Matus Carrillo et al (2023). After being ejected from the ISF, the decrease in gas within the ONC reduces the gravitational potential, resulting in the expansion and supervirial velocity dispersion.…”

“…We speculate that this can be attributed to the influence from the ISF, a gas filament associated with the ONC (Bally et al 1987). The ISF is believed to experience periodic oscillations in radial and on-sky directions (e.g., Stutz & Gould 2016;Stutz 2018;Matus Carrillo et al 2023). Protostars are ejected from the gas filaments during the oscillations, shutting off their accretion.…”

“…Possible explanations are the interaction with the ISF, such as the slingshot mechansim, which states that the ONC is ejected from the ISF due to the oscillation of the gas filament (Stutz & Gould 2016;Stutz 2018;Matus Carrillo et al 2023). 10.…”

“…Kounkel et al (2022) uses the data from Gaia DR3 and identifies a stellar age gradient as a function of their distance from us, implying that the star formation front is propagating into the star cluster possibly triggered by the shockwave from a supernova in the past. Evidence suggests that the ONC could form in the oscillating integral-shaped filament (ISF), a filamentary gas structure associated with the ONC (Bally et al 1987), and recently ejected from the ISF (Stutz & Gould 2016;Stutz 2018;Matus Carrillo et al 2023). Such a mechanism of producing protostars is referred to as slingshot scenario.…”