J/A+A/707/A85 Canis Major region with Gaia-DR3 (Nogueira-Silva+, 2026)
Re-visiting the Canis Major star-forming region with Gaia data release 3 data.
Nogueira-Silva S., Galli P.A.B., Olivares J., Bouy H., Popowicz B.P.,
Merino P.M., Santos-Silva T., Gregorio-Hetem J., Miret-Roig N., Alves J.
<Astron. Astrophys. 707, A85 (2026)>
=2026A&A...707A..85N 2026A&A...707A..85N (SIMBAD/NED BibCode)
ADC_Keywords: Associations, stellar ; Clusters, open ; Stars, distances ;
Radial velocities ; Space velocities ; Optical
Keywords: radial velocities - astrometry - parallaxes - star formation -
stars: kinematics and dynamics
Abstract:
The Canis Major (CMa) star-forming region, a remote molecular cloud
complex within the recently discovered Radcliffe Wave, remains
underexplored in literature.
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).
We conducted a membership analysis of Gaia-DR3 sources across a
16deg2 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
18mag in G band from Gaia DR3. We identified two subgroups of CMa
stars in our sample labeled as Cluster A and Cluster B. They are
located at roughly the same distance (dA=1150+79-88pc and
dB=1183+103-108pc) 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 2-3Myr.
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.
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 for further advancing our understanding of the history of
star formation in this region.
Description:
Kinematic properties of the Canis Major stars selected in our
membership analysis using Gaia-DR3 data. We provide for each star its
identifier, position, proper motion, parallax, radial velocity
measured in this study, distance, spatial velocity, and membership
probability. We also provide the membership probabilities for all
sources in the field surveyed by our study.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 108 1531 Properties of the 1531 cluster members in CMa
tablea2.dat 72 162331 Membership probability for all sources in
the field
tablea3.dat 160 90 Properties of the 90 members with radial velocity
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See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 -- --- [Gaia DR3]
10- 28 I19 --- GaiaDR3 Gaia-DR3 designation
30- 39 F10.6 deg RAdeg Right ascension (ICRS) at Ep=2016.0
(Gaia-DR3)
41- 49 F9.5 deg DEdeg Declination (ICRS) at Ep=2016.0 (Gaia-DR3)
51- 56 F6.3 mas/yr pmRA Proper motion in right ascension
58- 62 F5.3 mas/yr e_pmRA Proper motion error in right ascension
64- 68 F5.3 mas/yr pmDE Proper motion in declination
70- 74 F5.3 mas/yr e_pmDE Proper motion error in declination
76- 80 F5.3 mas plx Parallax
82- 86 F5.3 mas e_plx Parallax error
88- 93 F6.3 mag Gmag Magnitude in G band from Gaia-DR3
95- 99 F5.3 mag G-RP Colour (G-RP) from Gaia-DR3
101-106 F6.4 --- Pmemb Membership probability (from 0 to 1)
108 A1 --- Cluster CMa subgroup from clustering analysis
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 -- --- [Gaia DR3]
10- 28 I19 --- GaiaDR3 Gaia-DR3 designation
30- 39 E10.4 --- pin0p6 Membership probability with pin=0.6
41- 50 E10.4 --- pin0p7 Membership probability with pin=0.7
52- 61 E10.4 --- pin0p8 Membership probability with pin=0.8
63- 72 E10.4 --- pin0p9 Membership probability with pin=0.9
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- --- [Gaia DR3]
10- 28 I19 --- GaiaDR3 Gaia-DR3 designation
30- 39 F10.6 deg RAdeg Right ascension (ICRS) at Ep=2016.0
(Gaia-DR3)
41- 49 F9.5 deg DEdeg Declination (ICRS) at Ep=2016.0 (Gaia-DR3)
51- 56 F6.3 mas/yr pmRA Proper motion in right ascension
58- 62 F5.3 mas/yr e_pmRA Proper motion error in right ascension
64- 68 F5.3 mas/yr pmDE Proper motion in declination
70- 74 F5.3 mas/yr e_pmDE Proper motion error in declination
76- 80 F5.3 mas plx Parallax
82- 86 F5.3 mas e_plx Parallax error
88- 91 F4.1 km/s RV Radial velocity
93- 95 F3.1 km/s e_RV Radial velocity error
97-102 F6.1 pc Dist Distance
104-106 F3.1 pc E_Dist Distance error (plus)
108-111 F4.1 pc e_Dist Distance error (minus)
113-117 F5.1 km/s Uvel U-velocity
119-121 F3.1 km/s E_Uvel U-velocity error (plus)
123-126 F4.1 km/s e_Uvel U-velocity error (minus)
128-132 F5.1 km/s Vvel V-velocity
134-136 F3.1 km/s E_Vvel V-velocity error (plus)
138-141 F4.1 km/s e_Vvel V-velocity error (minus)
143-147 F5.1 km/s Wvel W-velocity
149-151 F3.1 km/s E_Wvel W-velocity error (plus)
153-156 F4.1 km/s e_Wvel W-velocity error (minus)
158 A1 --- Cluster CMa subgroup from clustering analysis
160 I1 --- Flag Flag for outlier rejection
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Acknowledgements:
Phillip Galli, phillip.galli(at)iag.usp.br
(End) Patricia Vannier [CDS] 28-Jan-2026