Gaia EDR3 distances of the young stellar clusters in the extended Carina Nebula complex

TL;DR

This study uses Gaia EDR3 data to accurately measure distances to young stellar clusters in the Carina Nebula, revealing they form a coherent star-forming complex at approximately 2.35 kpc, with a foreground cluster at 441 pc.

Contribution

It provides the first consistent distance measurements for multiple clusters in the Carina Nebula using Gaia EDR3 parallaxes, clarifying their physical connection.

Findings

Clusters in the Carina Nebula are at similar distances within 2%.

The mean distance to the clusters is approximately 2.35 kpc.

The foreground cluster vdBH 99 is at 441 pc and ~60 Myr old.

Abstract

Context: The Carina Nebula complex (CNC) is one of the most massive and active star-forming regions in our Galaxy and it contains several large young star clusters. The distances of the individual clusters and their physical connection were poorly known up to now, with strongly discrepant results reported in the literature. Aims: We want to determine reliable distances of the young stellar clusters in the central Carina Nebula region (in particular, Tr 14, 15, and 16) and the prominent clusters NGC 3324 and NGC 3293 in the northwestern periphery of the CNC. Methods: We analyzed the parallaxes in Gaia EDR3 for a comprehensive sample of 237 spectroscopically identified OB stars, as well as for 9562 X-ray-selected young stars throughout the complex. We also performed an astrometric analysis to identify members of the young cluster vdBH 99, which is located in the foreground of the northwestern part of the Carina Nebula. Results: We find that the distances of the investigated clusters in the CNC are equal within <= 2%, and yield very consistent most likely mean distance values of 2.36(+0.05 -0.05) kpc for the OB star sample and 2.34(+0.05 -0.06) kpc for the sample of X-ray-selected young stars. Conclusions: Our results show that the clusters in the CNC constitute a coherent star-forming region, in particular with regard to NGC 3324 and NGC 3293 at the northwestern periphery, which are (within <= 2%) at the same distance as the central Carina Nebula. For the foreground cluster vdBH 99, we find a mean distance of 441(+2 -2) pc and an age of ~ 60 Myr. We quantified the contamination of X-ray-selected samples of Carina Nebula stars based on members of this foreground cluster.