juliensimon/carbon-stars

Galactic Carbon Stars (GCCS)

Credit: NASA/ESA/Hubble

Part of a dataset collection on Hugging Face.

Dataset description

Catalog of 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.

The Stephenson GCCS (3rd Edition, Alksnis et al. 2001) is the definitive reference catalog of Galactic cool carbon stars, with equatorial positions, visual and infrared magnitudes, spectral types, and cross-identifications. Carbon stars are classified into several subtypes: C-N (classical cool AGB giants), C-R (warm carbon giants, possibly formed through binary mergers), C-J (strong 13C isotope features), C-H (high-velocity halo carbon stars), and C-Hd (hydrogen-deficient, R CrB type).

Carbon stars occupy a pivotal role in stellar evolution and galactic chemical enrichment. The defining characteristic — a C/O ratio greater than unity — arises primarily through the third dredge-up process on the AGB, where convective mixing carries freshly synthesized carbon-12 from the helium-burning shell to the surface. As luminous infrared sources (M_bol typically -3 to -6), carbon stars are detectable at large distances and serve as excellent tracers of intermediate-age stellar populations (1-4 Gyr).

Schema

Column	Type	Description	Sample	Null %
j_name	object	J2000 positional designation derived from RA/Dec (e.g. 'J191104.6+040429'); useful for cross-matching with other surveys	0005+6354	0.0%
cgcs_number	Int64	Sequential catalog number in the CGCS (Catalogue of Galactic Carbon Stars, Stephenson 1989, updated Alksnis et al. 2001); primary sort key and identifier	1	0.0%
ra_deg	float64	Right ascension, ICRS J2000.0, in decimal degrees (0-360)	1.3687499999999997	0.0%
dec_deg	float64	Declination, ICRS J2000.0, in decimal degrees (-90 to +90)	63.91472222222221	0.0%
b_mag	float64	Johnson B-band apparent magnitude; carbon stars are extremely red so B magnitudes are much fainter than V; null for many entries	14.0	81.5%
v_mag	float64	Johnson V-band apparent magnitude; carbon stars are very red, typical V = 6-14 mag; null for highly obscured AGB stars	15.1	45.8%
ir_mag	float64	Infrared magnitude from various surveys (band indicated by ir_mag_band); carbon stars are luminous IR sources due to circumstellar dust; null where no IR photometry available	12.6	35.6%
ir_mag_band	object	Photometric band identifier for ir_mag: indicates which IR survey/band the magnitude comes from (e.g. K, L, or IRAS band)	J	88.3%
spectral_type	object	Spectral classification string encoding carbon subclass (e.g. 'C-N5', 'C6,2', 'R0'); C-N = cool AGB giants, C-R = warm giants, C-J = enhanced 13C, C-H = halo; null for ~30% of entries	N(Ste),C6-,4(De)	71.1%
names	object	Cross-identification names from other catalogs (variable star designations, HD numbers, IRC numbers); multiple names separated by commas; null if no cross-IDs	VB 8023-29, MaeSoy 45	0.0%
notes	object	Catalog notes and remarks about the star (variability, binarity, spectral peculiarities); null for most entries	+	80.6%
priority	Int64	Priority code from the original Stephenson catalog indicating confidence of carbon star classification; integer scale	1	0.0%
has_ir_photometry	bool	True if ir_mag is non-null; useful filter for studies requiring infrared data	False	0.0%

Quick stats

• 6,891 Galactic carbon stars
• 1,991 with spectral classification
• 4,441 with infrared photometry
• V magnitude range: 4.5-23.0
• B magnitude range: 6.9-21.3

Usage

from datasets import load_dataset

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

# Stars with spectral classification
classified = df.dropna(subset=["spectral_type"])
print(f"{len(classified):,} stars with spectral type")

# V-band magnitude distribution
import matplotlib.pyplot as plt
fig, (ax1, ax2) = plt.subplots(1, 2, figsize=(14, 5))
df["v_mag"].dropna().hist(bins=40, ax=ax1, edgecolor="k", alpha=0.7)
ax1.set_xlabel("V magnitude")
ax1.set_ylabel("Count")
ax1.set_title("V-band Distribution")

# Sky distribution in Galactic coordinates
ax2.scatter(df["ra_deg"], df["dec_deg"], s=0.5, alpha=0.3, c="orangered")
ax2.set_xlabel("RA (deg)")
ax2.set_ylabel("Dec (deg)")
ax2.set_title("Galactic Carbon Stars — Sky Distribution")
ax2.invert_xaxis()
plt.tight_layout()
plt.show()

Data source

https://vizier.cds.unistra.fr/viz-bin/VizieR-3?-source=III/227

Related datasets

• juliensimon/wolf-rayet-stars

• juliensimon/brown-dwarf-catalog

• juliensimon/gcvs-variable-stars

Citation

@dataset{carbon_stars,
  title = {Galactic Carbon Stars (GCCS)},
  author = {juliensimon},
  year = {2026},
  url = {https://huggingface.co/datasets/juliensimon/carbon-stars},
  publisher = {Hugging Face}
}

License

VizieR Scientific-Use Terms