juliensimon/carbon-stars

---
license: cc-by-4.0
pretty_name: "Galactic Carbon Stars (GCCS)"
language:
- en
description: "Catalog of 6,891 Galactic carbon stars from the General Catalogue of Galactic Cool Carbon Stars (GCCS, 3rd Edition, Alksnis et al. 2001). Includes positions, magnitudes, spectral types, and identifications for carbon-rich AGB stars. Sourced via VizieR CDS Strasbourg."
task_categories:
- tabular-classification
tags:
- space
- stars
- carbon-stars
- agb
- evolved-stars
- spectroscopy
- astronomy
- open-data
- tabular-data
- parquet
size_categories:
- 1K<n<10K
configs:
- config_name: default
data_files:
- split: train
path: data/carbon_stars.parquet
default: true
---

# Galactic Carbon Stars (GCCS)

*Part of the [Astronomy Datasets](https://huggingface.co/collections/juliensimon/astronomy-datasets-69c24caf2f17e36128946743) collection on Hugging Face.*

Catalog of **6,891** Galactic carbon stars from the General Catalogue of Galactic Cool
Carbon Stars (GCCS, 3rd Edition). Carbon stars are evolved red giant branch / asymptotic giant
branch (AGB) stars whose atmospheres are enriched in carbon from internal nucleosynthesis
(dredge-up episodes). Their distinctive molecular bands (C2, CN, CH) make them important
tracers of stellar evolution and galactic structure.

## Dataset description

The Stephenson GCCS (3rd Edition, Alksnis et al. 2001) is the definitive reference catalog of
Galactic cool carbon stars, containing 6,891 entries with equatorial positions, visual and
infrared magnitudes, spectral types, and cross-identifications. Carbon stars are classified
into several subtypes based on their spectra:

- **C-N** — classical (cool) carbon stars on the AGB, the most common type
- **C-R** — warm carbon giants, possibly formed through binary mergers
- **C-J** — carbon stars with strong 13C isotope features
- **C-H** — high-velocity (halo) carbon stars, often CH stars
- **C-Hd** — hydrogen-deficient carbon stars (R CrB type)

## Schema

| Column | Type | Description |
|--------|------|-------------|
| `gccs_number` | int | GCCS catalog sequence number |
| `name` | string | Star identification / name |
| `ra_deg` | float64 | Right ascension (degrees) |
| `dec_deg` | float64 | Declination (degrees) |
| `spectral_type` | string | MK spectral type |
| `carbon_type` | string | Carbon star type classification |
| `carbon_class` | string | Broad carbon class (C-N, C-R, C-J, C-H, C-Hd) |
| `v_mag` | float64 | Visual (V-band) magnitude |
| `i_mag` | float64 | I-band magnitude |
| `j_mag` | float64 | J-band magnitude (2MASS) |
| `h_mag` | float64 | H-band magnitude (2MASS) |
| `k_mag` | float64 | K-band magnitude (2MASS) |
| `pm_ra_mas_yr` | float64 | Proper motion in RA (mas/yr) |
| `pm_dec_mas_yr` | float64 | Proper motion in Dec (mas/yr) |
| `has_ir_photometry` | bool | True if J or K magnitude available |

## Quick stats

- **6,891** Galactic carbon stars
- Type breakdown: classification not available
- **0** with infrared photometry (J or K band)
- V magnitude range: 4.5–23.0
- K magnitude range: N/A

## Usage

```python
from datasets import load_dataset

ds = load_dataset("juliensimon/carbon-stars", split="train")
df = ds.to_pandas()

# Carbon type distribution
print(df["carbon_class"].value_counts())

# Stars with IR photometry
ir = df[df["has_ir_photometry"]]
print(f"{len(ir):,} stars with IR photometry")

# Sky distribution
import matplotlib.pyplot as plt
plt.scatter(df["ra_deg"], df["dec_deg"], s=0.5, alpha=0.3)
plt.xlabel("RA (deg)")
plt.ylabel("Dec (deg)")
plt.title("Galactic Carbon Stars — Sky Distribution")
plt.gca().invert_xaxis()
```

## Data source

Alksnis, A., Balklavs, A., Dzervitis, U., Eglitis, I., Paupers, O. & Pundure, I. (2001),
"A catalogue of Galactic carbon stars", *Baltic Astronomy*, 10, 1.
Accessed via [VizieR](https://vizier.cds.unistra.fr/) (III/227), CDS Strasbourg.

## Related datasets

- [wolf-rayet-stars](https://huggingface.co/datasets/juliensimon/wolf-rayet-stars) — Galactic Wolf-Rayet Stars
- [brown-dwarf-catalog](https://huggingface.co/datasets/juliensimon/brown-dwarf-catalog) — Brown Dwarf Catalog
- [gcvs-variable-stars](https://huggingface.co/datasets/juliensimon/gcvs-variable-stars) — General Catalogue of Variable Stars

## Pipeline

Source code: [juliensimon/space-datasets](https://github.com/juliensimon/space-datasets)

## Support

If you find this dataset useful, please give it a ❤️ on the [dataset page](https://huggingface.co/datasets/juliensimon/carbon-stars) and share feedback in the Community tab! Also consider giving a ⭐️ to the [space-datasets](https://github.com/juliensimon/space-datasets) repo.

## Citation

```bibtex
@dataset{carbon_stars,
author = {Simon, Julien},
title = {Galactic Carbon Stars (GCCS)},
year = {2026},
publisher = {Hugging Face},
url = {https://huggingface.co/datasets/juliensimon/carbon-stars},
note = {Based on Alksnis et al. (2001), Baltic Astronomy 10, 1 — VizieR III/227}
}
```

## License

[CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/)