juliensimon/open-star-clusters

Open Star Clusters (Hunt & Reffert 2024)

The most comprehensive Gaia-era catalog of open star clusters, containing 7,167 clusters with positions, distances, ages, and membership counts derived from Gaia DR3.

Dataset description

Open clusters are gravitationally bound groups of stars that formed together from the same molecular cloud. They are key tracers of Galactic structure, stellar evolution, and the chemical enrichment history of the Milky Way disk. This catalog from Hunt & Reffert (2024) represents the most complete census of open clusters in the Gaia era, combining automated detection with careful validation.

Each entry includes sky coordinates, distance, parallax, age, extinction, number of members, and radial velocity where available.

Schema

Column	Type	Description
ra_deg	float64	Right ascension J2000 (degrees)
dec_deg	float64	Declination J2000 (degrees)
distance_pc	float64	Distance (parsecs)
parallax_mas	float64	Parallax (milliarcseconds)
log_age	float64	Logarithmic age (log10 years)
extinction_av	float64	Visual extinction A_V (mag)
n_members	float64	Number of identified members
radial_velocity_kms	float64	Radial velocity (km/s)

Quick stats

• 7,167 open clusters
• 0 with age estimates
• 5,749 with radial velocities

Usage

from datasets import load_dataset

ds = load_dataset("juliensimon/open-star-clusters", split="train")
df = ds.to_pandas()

# Nearby clusters (< 500 pc)
nearby = df[df["distance_pc"] < 500].sort_values("distance_pc")
print(f"{len(nearby):,} clusters within 500 pc")

# Young clusters (< 10 Myr)
young = df[df["log_age"] < 7.0]
print(f"{len(young):,} clusters younger than 10 Myr")

Data source

Hunt, E.L. & Reffert, S. (2024), "Improving the open cluster census. III. Using Gaia DR3", A&A, 686, A42. Accessed via VizieR, CDS Strasbourg.

Related datasets

• gcvs-variable-stars -- General Catalogue of Variable Stars
• pulsar-catalog -- ATNF Pulsar Catalogue

Pipeline

Source code: juliensimon/space-datasets

Citation

@dataset{open_star_clusters,
  author = {Simon, Julien},
  title = {Open Star Clusters (Hunt & Reffert 2024)},
  year = {2026},
  publisher = {Hugging Face},
  url = {https://huggingface.co/datasets/juliensimon/open-star-clusters},
  note = {Based on Hunt & Reffert (2024), A&A, 686, A42 via VizieR CDS Strasbourg}
}

License

CC-BY-4.0