English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We aim at understanding the  massive  star formation (MSF) limit  in the mass–size space of molecular structures recently proposed by Kauffmann &amp; Pillai. As a first step, we build on the property that power‐law density profiles for molecular clumps combined with a volume density threshold for the  overall  star formation naturally leads to mass–radius relations for molecular clumps containing given masses of star‐forming gas. Specifically, we show that the mass   m  clump   and radius   r  clump   of molecular clumps whose density profile slope is − p  and which contain a mass   m  th   of gas denser than a density threshold  ρ th   obeys the following: . In a second step, we use the relation between the mass of embedded clusters and the mass of their most massive star to estimate the minimum mass of the star‐forming gas needed to form a 10‐M ⊙  star. Assuming a star formation efficiency (SFE) of  SFE ≃ 0.30 , this gives . In a third step, we demonstrate that, for sensible choices of the clump density index ( p  ≃ 1.7) and of the cluster formation density threshold (  n  th ≃ 10 4   cm −3  ), the line of constant  in the mass–radius space of molecular structures equates to the MSF limit for spatial scales larger than 0.3 pc. Hence, the observationally inferred MSF limit of Kauffmann &amp; Pillai is consistent with a threshold in star‐forming gas mass beyond which the star‐forming gas reservoir is large enough to allow the formation of massive stars. For radii smaller than 0.3 pc, the MSF limit is shown to be consistent with the formation of a 10‐M ⊙  star ( m  th, crit ≃ 30 M ⊙  with  SFE ≃ 0.3 ) out of its individual pre‐stellar core of density threshold . The inferred density thresholds for the formation of star clusters and individual stars within star clusters match those previously suggested in the literature.

Volume density thresholds for overall star formation imply mass–size thresholds for massive star formation