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 examine the mass-dependence of the velocity dispersion of stars in theyoung cluster NGC 6530 to better understand how it formed. Using a large sampleof members we find that the proper motion velocity dispersion increases withstellar mass. While this trend is the opposite to that predicted if the clusterwere developing energy equipartition, it is in agreement with recent N-bodysimulations that find such a trend develops because of the Spitzer instability.In these simulations the massive stars sink to the centre of the cluster andform a self-gravitating system with a higher velocity dispersion. If thecluster has formed by the cool collapse of an initially substructureddistribution then this occurs within 1-2 Myr, in agreement with ourobservations of NGC 6530. We therefore conclude that NGC 6530 formed from muchmore extended initial conditions and has since collapsed to form the cluster wesee now. This cluster formation model is inconsistent with the idea that allstars form in dense, compact clusters and provides the first dynamical evidencethat star clusters can form by hierarchical mergers between subclusters.

Kinematic signatures of cluster formation from cool collapse in the Lagoon Nebula cluster NGC 6530