The emerging timescale of young star clusters regulated by cluster stellar mass

TL;DR

This study uses Hubble and James Webb observations to measure how quickly young star clusters emerge from their natal gas, revealing that more massive clusters disperse their surrounding material faster, impacting star formation theories.

Contribution

It provides the first empirical measurement of the emergence timescale of star clusters as a function of their stellar mass, informing models of star formation and feedback.

Findings

Massive clusters disperse their natal gas faster than lower-mass clusters.

A strong correlation exists between cluster mass and dispersal timescale.

Results constrain star formation and feedback simulations, emphasizing the role of massive clusters.

Abstract

Quantifying the timescales of star cluster emergence from their natal clouds remains one of the main challenges in understanding the star formation process. These timescales are fundamental measurements of the star formation cycle within galaxies, yet are difficult to constrain due to the complex interplay between stellar feedback and star formation across multiple physical scales. Here we present Hubble Space Telescope and James Webb Space Telescope observations of thousands of young star clusters in four nearby galaxies (M51, M83, NGC 628 and NGC 4449). A substantial fraction of these clusters are still embedded within their natal gas and remain invisible at optical wavelengths. We constrain their emergence process by measuring the timescales required to disperse the surrounding material. We find a strong correlation between dispersal timescale and cluster stellar mass, with massive clusters emerging faster than their lower-mass counterparts. This is a critical constraint on star formation and stellar feedback simulations, which struggle to fully reproduce star clusters formation and emergence. Our results emphasize the central role of massive clusters in driving the escape of ionizing radiation into the galactic medium. Finally, they impose time limitations for planet formation in massive cluster environments where disks get exposed to ultraviolet irradiation and further gas infall is halted.