juliensimon/gaia-dr3-compact-companions
Gaia DR3 Compact Companion Candidates Credit: NASA/JPL-Caltech Part of a dataset collection on Hugging Face. Dataset description The Gaia DR3 Compact Companion Candidates catalog contains ~6,300 candidates for binary systems where a normal (luminous) star orbits an unseen compact object — a white dwarf, neutron star, or black hole. These candidates were identified by the Gaia DR3 variability processing pipeline through the detection of ellipsoidal… See the full description on the dataset page: https://huggingface.co/datasets/juliensimon/gaia-dr3-compact-companions.
Gaia DR3 Compact Companion Candidates
<div align="center"> <img src="banner.jpg" alt="Artist's concept of a black hole binary system" width="400"> <p><em>Credit: NASA/JPL-Caltech</em></p> </div>
Part of a [dataset collection](https://huggingface.co/collections/juliensimon/astronomy-datasets-69c24caf2f17e36128946743) on Hugging Face.
Dataset description
The Gaia DR3 Compact Companion Candidates catalog contains ~6,300 candidates for binary systems where a normal (luminous) star orbits an unseen compact object — a white dwarf, neutron star, or black hole. These candidates were identified by the Gaia DR3 variability processing pipeline through the detection of ellipsoidal variations in the primary star's light curve.
Ellipsoidal variability arises when the primary star is tidally distorted into a prolate ellipsoid by the gravitational pull of its compact companion. As the system orbits, the projected cross-section of the distorted star changes, producing a characteristic double-humped light curve at half the true orbital period. Because the compact companion emits negligible light compared to the primary, no eclipse is required — the signal is purely photometric, making this technique uniquely sensitive to quiescent (non-accreting) compact objects that are invisible to X-ray telescopes.
The minimum mass ratio columns (modminmassratio, modminmassratioonesigma, modminmassratiothree_sigma) constrain the companion mass assuming a range of orbital inclinations. A 3-sigma minimum mass ratio exceeding ~0.6 means the companion is too massive to be a main-sequence star at any plausible inclination, strongly suggesting a degenerate remnant. The alpha parameter encodes the ellipsoidal amplitude, which depends on the tidal distortion strength and therefore on the companion-to-primary mass ratio and the orbital separation.
This catalog represents one of the largest systematic searches for quiescent black hole and neutron star binaries ever conducted, and directly complements X-ray binary catalogs (HMXBs, LMXBs) which only detect systems currently undergoing active accretion. Identifying the dormant population is essential for constraining the true space density of stellar-mass black holes and the rate of compact object formation from stellar evolution.
This dataset is suitable for tabular classification, tabular regression tasks.
Schema
Quick stats
- 6,306 compact companion candidates
- 319 likely compact objects (3-sigma mass ratio > 0.5)
- Median orbital period: 0.4152 days (range: 0.250 – 2.5 days)
- Median minimum mass ratio: 0.7019
Usage
from datasets import load_dataset
ds = load_dataset("juliensimon/gaia-dr3-compact-companions", split="train")
df = ds.to_pandas()from datasets import load_dataset
ds = load_dataset("juliensimon/gaia-dr3-compact-companions", split="train")
df = ds.to_pandas()
# Likely compact companions (neutron star / black hole candidates)
compact = df[df["likely_compact"] == True]
print(f"Likely compact companions: {len(compact):,}")
# Period vs mass ratio scatter (highlight compact candidates)
import matplotlib.pyplot as plt
fig, ax = plt.subplots(figsize=(10, 6))
mask = df["likely_compact"]
ax.scatter(df.loc[~mask, "period"], df.loc[~mask, "mod_min_mass_ratio_three_sigma"],
s=5, alpha=0.4, label="Other", color="steelblue")
ax.scatter(df.loc[mask, "period"], df.loc[mask, "mod_min_mass_ratio_three_sigma"],
s=10, alpha=0.7, label="Likely compact", color="crimson")
ax.set_xlabel("Period (days)")
ax.set_ylabel("Min mass ratio (3σ)")
ax.set_xscale("log")
ax.legend()
plt.title("Gaia DR3 Compact Companion Candidates")
plt.show()
# Period histogram
df["period"].hist(bins=100, log=True)
plt.xlabel("Period (days)")
plt.ylabel("Count")
plt.title("Orbital Period Distribution")
plt.show()Data source
https://gea.esac.esa.int/archive/
Related datasets
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About the author
Created by Julien Simon — AI Operating Partner at Fortino Capital. Part of the Space Datasets collection.
Citation
@dataset{gaia_dr3_compact_companions,
title = {Gaia DR3 Compact Companion Candidates},
author = {Simon, Julien},
year = {2026},
url = {https://huggingface.co/datasets/juliensimon/gaia-dr3-compact-companions},
publisher = {Hugging Face},
note = {Derived from ESA Gaia Archive, https://gea.esac.esa.int/archive/}
}