# Unveiling a cluster of protostellar disks around the massive protostar GGD27 MM1

## TL;DR

This study used ALMA to observe a young star-forming region, revealing a cluster of protostellar disks with properties indicating early evolutionary stages and limited external influence, demonstrating the capability to analyze disks in distant, embedded clusters.

## Contribution

First high-resolution ALMA observations of GGD27 uncover a cluster of 25 protostellar disks, providing insights into their sizes, masses, and the cluster's youthfulness, advancing understanding of disk evolution in massive star-forming regions.

## Key findings

- Detected 25 protostellar disks with masses 0.003-0.05 Msun.
- Disks have median radius of 34 au, smaller than Taurus.
- Lack of disk mass segregation suggests early evolutionary stage.

## Abstract

We used ALMA to observe the star-forming region GGD27 at 1.14 mm with an unprecedented angular resolution, 40 mas (56 au) and sensitivity (0.002 Msun). We detected a cluster of 25 continuum sources, most of which are likely tracing disks around Class 0/I protostars. Excluding the two most massive objects, disks masses are in the range 0.003-0.05 Msun. The analysis of the cluster properties indicates that GGD27 displays moderate subclustering. This result combined with the dynamical timescale of the radio jet (10000 years) suggests the youthfulness of the cluster. The lack of disk mass segregation signatures may support this too. We found a clear paucity of disks with Rdisk >100 au. The median value of the radius is 34 au, smaller than the median of 92 au for Taurus but comparable to the value found in Ophiuchus and in the Orion Nebula Cluster. In GGD27 there is no evidence of a distance-dependent disk mass distribution (i. e., disk mass depletion due to external photoevaporation), most likely due to the cluster youth. There is a clear deficit of disks for distances <0.02 pc. Only for distances >0.04 pc stars can form larger and more massive disks, suggesting that dynamical interactions far from the cluster center are weaker, although the small disks found could be the result of disk truncation. This work demonstrates the potential to characterize disks from low-mass YSOs in distant and massive (still deeply embedded) clustered environments.