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Stars form in dense cores within molecular clouds, and newly formed stars influence their natal environments. How stellar feedback impacts core properties and evolution has been the subject of extensive investigation. We performed a hierarchical clustering (dendrogram) analysis of a STARFORGE (STAR FORmation in Gaseous Environments) simulation, modelling a giant molecular cloud to identify gas overdensities (cores) and study changes in their radius, mass, velocity dispersion, and virial parameter with respect to stellar feedback. We binned these cores on the basis of the fraction of gas affected by protostellar outflows, stellar winds, and supernovae and analysed the property distributions for each feedback bin. We find that cores that experience more feedback influence are smaller. Feedback notably enhances the velocity dispersion and virial parameter of the cores, more so than it reduces their radius. This is also evident in the linewidth–size relation, according to which cores in higher-feedback bins exhibit higher velocities than their similarly sized pristine counterparts. We conclude that stellar feedback mechanisms, which impart momentum to the molecular cloud, simultaneously compress and disperse the dense molecular gas.
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This content will become publicly available on March 25, 2026
The Life and Times of Star-forming Cores: An Analysis of Dense Gas in the STARFORGE Simulations
Dense gas in molecular clouds is an important signature of ongoing and future star formation. We identify and track dense cores in the Starforge simulations, following the core evolution from birth through dispersal by stellar feedback for typical Milky Way cloud conditions. Only ∼8% of cores host protostars, and most disperse before forming stars. The median starless and protostellar core lifetimes are ∼0.5–0.6 Myr and ∼0.8–1.1 Myr, respectively, where the protostellar phase lasts 0.1 Myr. While core evolution is stochastic, we find that virial ratios and line widths decline in prestellar cores, coincident with turbulent decay. Collapse occurs over ∼0.1 Myr, once the central density exceeds ≳106cm−3. Starless cores, only, follow line-width–size and mass–size relations,σ∝R0.3andM∝R1. The core median mass, radius, and velocity dispersion scale weakly with the cloud magnetic field strength. We cluster the core properties and find that protostellar cores have >80% likelihood of belonging to three particular groups that are characterized by high central densities, compact radii, and lower virial parameters. Overall, core evolution appears to be universally set by the interplay of gravity and magnetized turbulence, while stellar feedback dictates protostellar core properties and sets the protostellar phase lifetime.
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- PAR ID:
- 10625498
- Publisher / Repository:
- ApJ
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 982
- Issue:
- 2
- ISSN:
- 0004-637X
- Page Range / eLocation ID:
- 138
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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