archive / atlas record
Cygnus X-1
A historic X-ray source in a binary system.
- classification
- Stellar-mass black hole candidate
- system
- Binary star system
Cygnus X-1 is a compact object drawing material from a massive companion. Multiple measurements support its identification as a stellar-mass black hole.
- Class
- Stellar-mass black hole candidate
- Location / system
- Binary star system
- Distance
- About 7,000 light-years from Earth
Only values with an established scientific consensus are listed. Where a quantity is uncertain or model-dependent, it is discussed in the sections below rather than stated as data.
Overview (starter entry, expanded review pending)
Cygnus X-1 is a compact object drawing material from a massive companion. Multiple measurements support its identification as a stellar-mass black hole.
Gravity and high-energy observation
Cygnus X-1 is inferred from the motion and radiation of surrounding matter. Mass estimates are model-dependent rather than direct pictures of an interior.
- What remains least constrained about Cygnus X-1?Composition, internal structure, formation history or local environment can require different observations and may remain model-dependent.
Items above are unresolved. Hypotheses are labelled as such and are not presented as confirmed findings.
NASA/IPAC // verified 28 September 2026
CDS Strasbourg // verified 28 September 2026