Re-visiting the Canis Major star-forming region with Gaia data release 3 data

TL;DR

This study uses Gaia DR3 data to identify and characterize new stellar members, subgroups, and their properties in the Canis Major star-forming region, revealing insights into its structure, kinematics, and age.

Contribution

The paper provides the first comprehensive stellar census of Canis Major using Gaia DR3, identifying new members and subgroups, and analyzing their kinematics and evolutionary stages.

Findings

Identified 1130 new candidate members of Canis Major.

Located two subgroups at approximately 1150-1183 pc distance.

Estimated the subgroups' ages to be about 2-3 million years.

Abstract

Context: The Canis Major (CMa) star-forming region, a remote molecular cloud complex within the recently discovered Radcliffe Wave, remains under-explored in the literature. Aims: We revisit the stellar census in the CMa region, characterizing its stellar population, kinematics, and age using recent astrometric and photometric data from the third data release of the Gaia space mission (Gaia DR3). Methods: We conducted a membership analysis of Gaia DR3 sources across a 16 deg$^2$ field encompassing the youngest subgroups in CMa. This new stellar census, combined with spectroscopic observations, allowed us to investigate the structure, kinematics, and age of this region. Results: We identified 1531 objects as members of the CMa region, confirming 401 previously known members and introducing 1130 new candidate members. These objects have magnitudes ranging from 10 to 18 mag in the G band from Gaia DR3. We identified two subgroups of CMa stars in our sample labelled as Cluster A and Cluster B. They are located at roughly the same distance ($d_{A} = 1150^{+79}_{-88}$ pc and $d_{B} = 1183^{+103}_{-108}$ pc) and exhibit similar space motions that can be derived thanks to the precise radial velocities obtained in this study. The subgroups have a mean isochronal age of about 2-3 Myr. However, based on infrared photometry we show that Cluster A has a higher fraction of disc-bearing stars suggesting that it could be somewhat younger than Cluster B. Conclusions: Our analysis provides new insights into the stellar population of the Canis Major region, by identifying new members, characterizing their kinematics, and assessing their evolutionary stages. Future studies incorporating additional data from upcoming Gaia data releases, multi-wavelength and high-resolution spectroscopic observations will be essential to further advance our understanding of the history of star formation in this region.