The Montreal Open Clusters and Associations (MOCA) Database: A Census of Nearby Associations, Open Clusters, and Young Substellar Objects within 500 pc of the Sun
7 affiliations
- 1Planétarium de Montréal
- 2Université de Montréal
- 3American Museum of Natural History
- 4Columbia University
- 5The Open University
- 6The University of Western Ontario
- 7California Institute of Technology
Abstract
We present the Montreal Open Clusters and Associations database (MOCAdb), a public MySQL database with a Python interface. MOCAdb provides a census of memberships for 10,259 associations and open clusters, with a comprehensive compilation of literature measurements such as spectral types, kinematics, rotation periods, activity indices, spectral indices, and photometry. All known substellar objects are cataloged in MOCAdb, along with 2943 public spectra, to enable the characterization of substellar association members. MOCAdb also features periodically updated calculations such as Galactic UVW space velocities. We use this compilation to construct mappings between independent association definitions and to update the BANYAN Σ membership classification tool, which now includes 8125 associations. The BANYAN Σ model construction is improved to account for heterogeneous and correlated errors and to capture complex association shapes using Gaussian mixture models. Combined with Gaia DR3, this enabled us to identify 11,535 yet unrecognized candidate members of young associations within 500 pc, mostly M dwarfs. Our results corroborate a recent observation that systematics up to ≈4 km s ⁻¹ remain in Gaia DR3 radial velocities for A-type stars. We present an updated census of age-calibrated exoplanets and substellar objects: 134 age-calibrated exoplanet systems (plus 121 TESS exoplanet candidates), 99 of which did not appear to have known memberships so far, and 455 substellar (L0 or later) candidate members of young associations, 196 of which appear newly recognized. We bring the total of candidate isolated planetary-mass objects to 101, of which 53 are newly recognized candidate members.
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BibTeX
@article{gagne2026montreal,
title = {{The Montreal Open Clusters and Associations (MOCA) Database: A Census of Nearby Associations, Open Clusters, and Young Substellar Objects within 500 pc of the Sun}},
author = {Jonathan Gagné and Leslie Moranta and Jacqueline K. Faherty and Jason Lee Curtis and Thomas P. Bickle and Dominic Couture and Amélie Chiasson David and Katie Christie and Samantha Lambier and Elise Leclerc and Livia Poliquin and Danika Belzile and Eric E. Mamajek},
journal = {The Astrophysical Journal Supplement Series},
year = {2026},
month = oct,
doi = {10.3847/1538-4365/ae9b09},
url = {https://iopscience.iop.org/article/10.3847/1538-4365/ae9b09},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - The Montreal Open Clusters and Associations (MOCA) Database: A Census of Nearby Associations, Open Clusters, and Young Substellar Objects within 500 pc of the Sun
AU - Jonathan Gagné
AU - Leslie Moranta
AU - Jacqueline K. Faherty
AU - Jason Lee Curtis
AU - Thomas P. Bickle
AU - Dominic Couture
AU - Amélie Chiasson David
AU - Katie Christie
AU - Samantha Lambier
AU - Elise Leclerc
AU - Livia Poliquin
AU - Danika Belzile
AU - Eric E. Mamajek
PY - 2026
DA - 2026/10/13
JO - The Astrophysical Journal Supplement Series
DO - 10.3847/1538-4365/ae9b09
UR - https://iopscience.iop.org/article/10.3847/1538-4365/ae9b09
AB - We present the Montreal Open Clusters and Associations database (MOCAdb), a public MySQL database with a Python interface. MOCAdb provides a census of memberships for 10,259 associations and open clusters, with a comprehensive compilation of literature measurements such as spectral types, kinematics, rotation periods, activity indices, spectral indices, and photometry. All known substellar objects are cataloged in MOCAdb, along with 2943 public spectra, to enable the characterization of substellar association members. MOCAdb also features periodically updated calculations such as Galactic UVW space velocities. We use this compilation to construct mappings between independent association definitions and to update the BANYAN Σ membership classification tool, which now includes 8125 associations. The BANYAN Σ model construction is improved to account for heterogeneous and correlated errors and to capture complex association shapes using Gaussian mixture models. Combined with Gaia DR3, this enabled us to identify 11,535 yet unrecognized candidate members of young associations within 500 pc, mostly M dwarfs. Our results corroborate a recent observation that systematics up to ≈4 km s ⁻¹ remain in Gaia DR3 radial velocities for A-type stars. We present an updated census of age-calibrated exoplanets and substellar objects: 134 age-calibrated exoplanet systems (plus 121 TESS exoplanet candidates), 99 of which did not appear to have known memberships so far, and 455 substellar (L0 or later) candidate members of young associations, 196 of which appear newly recognized. We bring the total of candidate isolated planetary-mass objects to 101, of which 53 are newly recognized candidate members.
SN - 0067-0049
SN - 1538-4365
ER -