| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Circinus |
| Right ascension | 15h 20m 40.85s[1] |
| Declination | −57° 10′ 00.1″[1] |
| Apparent magnitude (V) | 21.40[2] |
| Characteristics | |
| Spectral type | B5–A0 I[3] |
| Variable type | HMXB[4] |
| Astrometry | |
| Distance | 31000+2600 −3300 ly (9400+800 −1000[5] pc) |
| Orbit[3] | |
| Period (P) | 16.68 ± 0.15 d |
| Eccentricity (e) | 0.45 ± 0.07 |
| Periastron epoch (T) | JD 2453473.8 ± 0.4 |
| Argument of periastron (ω) (secondary) | 2 ± 12° |
| Semi-amplitude (K1) (primary) | 25 ± 2 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Circinus X-1 is an X-ray binary star system that includes a neutron star. Observation of Circinus X-1 in July 2007 revealed the presence of X-ray jets normally found in black hole systems; it is the first of the sort to be discovered that displays this similarity to black holes. Circinus X-1 may be among the youngest X-ray binaries observed.
- ^ a b Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C. S2CID 115529446.
- ^ Liu, Q. Z; Van Paradijs, J; Van Den Heuvel, E. P. J (2007). "A catalogue of low-mass X-ray binaries in the Galaxy, LMC, and SMC (Fourth edition)". Astronomy & Astrophysics. 469 (2): 807. arXiv:0707.0544. Bibcode:2007A&A...469..807L. doi:10.1051/0004-6361:20077303. S2CID 14673570.
- ^ a b Jonker, P. G; Nelemans, G; Bassa, C. G (2007). "Detection of the radial velocity curve of the B5-A0 supergiant companion star of Cir X-1?". Monthly Notices of the Royal Astronomical Society. 374 (3): 999–1005. arXiv:astro-ph/0605497. Bibcode:2007MNRAS.374..999J. doi:10.1111/j.1365-2966.2006.11210.x. S2CID 7474465.
- ^ a b "V* BR Cir". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 22 September 2017.
- ^ Heinz, S; Burton, M; Braiding, C; Brandt, W. N; Jonker, P. G; Sell, P; Fender, R. P; Nowak, M. A; Schulz, N. S (2015). "Lord of the Rings: A Kinematic Distance to Circinus X-1 from a Giant X-Ray Light Echo Lord of the Rings: A Kinematic Distance to Circinus X-1 from a Giant X-Ray Light Echo". The Astrophysical Journal. 806 (2): 265. arXiv:1506.06142. Bibcode:2015ApJ...806..265H. doi:10.1088/0004-637X/806/2/265. S2CID 17657655.