Star cluster formation from turbulent clumps. IV. Protoplanetary disc evolution

TL;DR

This study models how star cluster environments, including dynamical interactions and radiation, influence the evolution and diversity of protoplanetary discs during star formation.

Contribution

It introduces a combined simulation approach to assess the effects of cluster formation parameters on protoplanetary disc evolution, emphasizing external photoevaporation over dynamical interactions.

Findings

External photoevaporation dominates disc dispersal.

Cluster formation efficiency and density significantly affect disc properties.

Primordial binarity influences disc mass and size.

Abstract

Most stars are born in the crowded environments of gradually forming star clusters. Dynamical interactions between close-passing stars and the evolving UV radiation fields from proximate massive stars are expected to sculpt the protoplanetary discs in these clusters, potentially contributing to the diversity of planetary systems that we observe. Here, we investigate the impact of cluster environment on disc demographics by implementing simple protoplanetary disc evolution models within $N$-body simulations of gradual star cluster formation. We consider a range of star formation efficiency per free-fall time, $\epsilon_{\rm ff}$, and mass surface density of the natal cloud environment, $\Sigma_{\rm cl}$, both of which affect the overall duration of cluster formation. We track the interaction history of all stars to estimate the dynamical truncation of the discs around stars involved in close encounters. We also track external photoevaporation of the discs due to the ionizing radiation field of the nearby high- and intermediate-mass ($> 5 M_\odot$) stars. We find that $\epsilon_{\rm ff}$, $\Sigma_{\rm cl}$, and the degree of primordial binarity have major influences on the masses and radii of the disc population. In particular, external photo-evaporation has a greater impact than dynamical interactions in determining the fate of discs in our clusters.