A double cluster at the core of 30 Doradus

TL;DR

This study identifies two distinct stellar populations in the core of 30 Doradus, revealing an ongoing merger of sub-clusters that supports hierarchical models of star formation.

Contribution

It provides the first observational evidence of a double cluster in 30 Doradus, highlighting a merger process consistent with hierarchical cloud fragmentation models.

Findings

Two stellar populations with different ages and locations

Support for hierarchical merging in star cluster formation

Evidence of ongoing cluster merger in 30 Doradus

Abstract

Based on an analysis of data obtained with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) we report the identification of two distinct stellar populations in the core of the giant HII region 30Doradus in the Large Magellanic Cloud. The most compact and richest component coincides with the center of R136 and is ~1 Myr younger than a second more diffuse clump, located ~5.4 pc toward the northeast. We note that published spectral types of massive stars in these two clumps lend support to the proposed age difference. The morphology and age difference between the two sub-clusters suggests that an ongoing merger may occurring within the core of 30Doradus. This finding is consistent with the predictions of models of hierarchical fragmentation of turbulent giant molecular clouds, according to which star clusters would be the final products of merging smaller sub-structures.