Datasets:

juliensimon
/

globular-star-clusters

+---
+license: cc-by-4.0
+pretty_name: "Milky Way Globular Star Clusters"
+language:
+  - en
+description: "Comprehensive catalog of 170 Milky Way globular clusters merging the Harris (2010) and Baumgardt databases. Includes positions, distances, metallicities, masses, velocity dispersions, structural parameters, and photometry."
+task_categories:
+  - tabular-classification
+  - tabular-regression
+tags:
+  - space
+  - globular-clusters
+  - stars
+  - milky-way
+  - astronomy
+  - open-data
+  - tabular-data
+size_categories:
+  - n<1K
+configs:
+  - config_name: default
+    data_files:
+      - split: train
+        path: data/globular_star_clusters.parquet
+    default: true
+---
+# Milky Way Globular Star Clusters
+*Part of the [Astronomy Datasets](https://huggingface.co/collections/juliensimon/astronomy-datasets-67ac2ada12aceb39f8feca3b) collection on Hugging Face.*
+A comprehensive catalog of **170** Milky Way globular clusters, merging two authoritative sources:
+the [Harris (2010 edition)](https://physics.mcmaster.ca/~harris/mwgc.dat) catalog for metallicities and
+photometry, and the [Baumgardt globular cluster database](https://people.smp.uq.edu.au/HolgerBaumgardt/globular/)
+for dynamical masses, velocity dispersions, and structural parameters from N-body model fits to
+Gaia DR3 proper motions and HST data.
+## Dataset description
+Globular clusters are ancient, gravitationally bound collections of stars orbiting the Milky Way.
+They are among the oldest objects in the Galaxy (10--13 Gyr), with typical masses of
+10⁴--10⁶ M☉ and half-light radii of a few parsecs. Their metallicities, dynamics,
+and spatial distribution encode the formation and assembly history of the Milky Way.
+This dataset combines Harris (2010) photometric and chemical data with Baumgardt's dynamical
+parameters derived from N-body fits to modern astrometric and spectroscopic data, providing
+the most complete per-cluster view available.
+## Schema
+| Column | Type | Description |
+|--------|------|-------------|
+| `name` | string | Cluster name (e.g. "NGC 104", "Pal 5") |
+| `ra_deg` / `dec_deg` | float64 | Position in decimal degrees (J2000) |
+| `distance_kpc` | float64 | Distance from the Sun (kpc) |
+| `distance_err_kpc` | float64 | Distance uncertainty (kpc) |
+| `distance_gc_kpc` | float64 | Galactocentric distance (kpc) |
+| `metallicity_fe_h` | float64 | Metallicity [Fe/H] (dex) |
+| `reddening_e_bv` | float64 | Foreground reddening E(B−V) |
+| `apparent_mag_v` | float64 | Apparent integrated V magnitude |
+| `absolute_mag_v` | float64 | Absolute integrated V magnitude |
+| `color_u_b` / `color_b_v` / `color_v_r` / `color_v_i` | float64 | Integrated color indices |
+| `spectral_type` | string | Integrated spectral type |
+| `ellipticity` | float64 | Projected ellipticity e = 1−b/a |
+| `mass_msun` | float64 | Total cluster mass (M☉) |
+| `mass_err_msun` | float64 | Mass uncertainty |
+| `mass_to_light_v` | float64 | V-band mass-to-light ratio (M☉/L☉) |
+| `log_initial_mass_msun` | float64 | Log₁₀ initial mass (M☉) |
+| `dissolution_time_gyr` | float64 | Predicted dissolution time (Gyr) |
+| `core_radius_pc` | float64 | Core radius (pc) |
+| `half_light_radius_pc` | float64 | Projected half-light radius (pc) |
+| `half_mass_radius_pc` | float64 | 3D half-mass radius (pc) |
+| `tidal_radius_pc` | float64 | Tidal radius (pc) |
+| `log_central_density_msun_pc3` | float64 | Log₁₀ central density (M☉/pc³) |
+| `log_half_mass_density_msun_pc3` | float64 | Log₁₀ half-mass density (M☉/pc³) |
+| `log_half_mass_relaxation_time_yr` | float64 | Log₁₀ half-mass relaxation time (yr) |
+| `velocity_dispersion_km_s` | float64 | Central velocity dispersion (km/s) |
+| `escape_velocity_km_s` | float64 | Central escape velocity (km/s) |
+| `radial_velocity_km_s` | float64 | Heliocentric radial velocity (km/s) |
+| `anisotropy_central` / `anisotropy_half_mass` | float64 | Velocity anisotropy (η) |
+| `rotation_amplitude_km_s` | float64 | Rotation amplitude (km/s) |
+| `rotation_probability_pct` | float64 | Probability of significant rotation (%) |
+| `mass_function_slope` | float64 | Present-day mass function slope (α) |
+| `n_radial_velocity_stars` | int | Stars with radial velocity measurements |
+| `n_proper_motion_stars` | int | Stars with proper motion measurements |
+| `core_collapsed` | bool | Core-collapsed cluster (Harris) |
+| `concentration_harris` | float64 | King-model concentration c = log(r_t/r_c) |
+## Quick stats
+- **170** Milky Way globular clusters
+- **167** with dynamical mass estimates (7.46e+02–3.94e+06 M☉)
+- **152** with metallicity measurements (-2.37 to 0.00 dex)
+- **167** with central velocity dispersions
+- **29** identified as core-collapsed
+## Usage
+```python
+from datasets import load_dataset
+ds = load_dataset("juliensimon/globular-star-clusters", split="train")
+df = ds.to_pandas()
+# Most massive clusters
+massive = df.nlargest(10, "mass_msun")[["name", "mass_msun", "metallicity_fe_h"]]
+# Metal-poor vs metal-rich populations
+metal_poor = df[df["metallicity_fe_h"] < -1.5]
+metal_rich = df[df["metallicity_fe_h"] >= -1.5]
+# Core-collapsed clusters
+cc = df[df["core_collapsed"]]
+# Mass-metallicity relation
+import matplotlib.pyplot as plt
+plt.scatter(df["metallicity_fe_h"], df["mass_msun"].apply(lambda x: x if x else None))
+plt.xlabel("[Fe/H]"); plt.ylabel("Mass (M☉)"); plt.yscale("log")
+```
+## Data sources
+1. **Harris (2010 edition)**: [McMaster Globular Cluster Catalog](https://physics.mcmaster.ca/~harris/mwgc.dat).
+   Please cite [Harris (1996), AJ 112, 1487](https://ui.adsabs.harvard.edu/abs/1996AJ....112.1487H) — 2010 edition.
+2. **Baumgardt Globular Cluster Database**: [https://people.smp.uq.edu.au/HolgerBaumgardt/globular/](https://people.smp.uq.edu.au/HolgerBaumgardt/globular/).
+   Please cite [Baumgardt & Hilker (2018), MNRAS 478, 1520](https://ui.adsabs.harvard.edu/abs/2018MNRAS.478.1520B).
+## Related datasets
+- [open-star-clusters](https://huggingface.co/datasets/juliensimon/open-star-clusters) — Milky Way open clusters
+- [stellar-streams](https://huggingface.co/datasets/juliensimon/stellar-streams) — Tidal stellar streams
+- [pulsars](https://huggingface.co/datasets/juliensimon/pulsars) — ATNF Pulsar Catalogue
+## Pipeline
+Source code: [juliensimon/space-datasets](https://github.com/juliensimon/space-datasets)
+## Citation
+```bibtex
+@dataset{globular_star_clusters,
+  author = {Simon, Julien},
+  title = {Milky Way Globular Star Clusters},
+  year = {2026},
+  publisher = {Hugging Face},
+  url = {https://huggingface.co/datasets/juliensimon/globular-star-clusters},
+  note = {Merged from Harris (1996, 2010 edition) and Baumgardt et al. globular cluster databases}
+}
+```
+## License
+[CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/)

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