4 Centauri is a star in the constellation Centaurus. It is a blue-white B-type subgiant with an apparent magnitude of +4.75 and is approximately 640 light years from Earth.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 13h 53m 12.53953s[1] |
| Declination | −31° 55′ 39.3947″[1] |
| Apparent magnitude (V) | +4.73[2](+4.72[3] / +8.47[4]) |
| Characteristics | |
| Spectral type | B6IV[5] / Am[5] |
| U−B color index | −0.56[2] |
| B−V color index | −0.14[2] |
| Astrometry | |
| Radial velocity (Rv) | +5.2 ± 2[6] km/s |
| Proper motion (μ) | RA: -12.72[1] mas/yr Dec.: -9.48[1] mas/yr |
| Parallax (π) | 5.12 ± 0.70 mas[1] |
| Distance | approx. 640 ly (approx. 200 pc) |
| Absolute magnitude (MV) | −1.66[7] |
| Orbit[5] | |
| Primary | 4 Cen Aa |
| Companion | 4 Cen Ab |
| Period (P) | 6.930137 ± 0.000015 |
| Eccentricity (e) | 0.25 ± 0.10 |
| Periastron epoch (T) | 2418823.406 ± 0.10 |
| Argument of periastron (ω) (secondary) | 152 ± 17° |
| Semi-amplitude (K1) (primary) | 21.0 ± 1.5 km/s |
| Orbit[5] | |
| Primary | 4 Cen Ba |
| Companion | 4 Cen Bb |
| Period (P) | 4.8390 ± 0.0001 |
| Eccentricity (e) | 0.05 ± 0.02 |
| Periastron epoch (T) | 2442916.55 ± 0.09 |
| Argument of periastron (ω) (secondary) | 51 ± 20° |
| Semi-amplitude (K1) (primary) | 16.9 ± 3.5 km/s |
| Other designations | |
| 4 Cen A[8]: SAO 204944, GC 18755, CD–31° 10729[9] | |
| 4 Cen B: SAO 204943, GC 18754, CD–31° 10727[10] | |
| Database references | |
| SIMBAD | 4 Cen |
| 4 Cen A | |
| 4 Cen B | |
4 Centauri is a hierarchical quadruple star system. The primary component of the system, 4 Centauri A, is a spectroscopic binary, meaning that its components cannot be resolved but periodic Doppler shifts in its spectrum show that it must be orbiting. 4 Centauri A has an orbital period of 6.927 days and an eccentricity of 0.23. Because light from only one of the stars can be detected (i.e. it is a single-lined spectroscopic binary), some parameters such as its inclination are unknown.[11] The secondary component, is also a single-lined spectroscopic binary. It has an orbital period of 4.839 days and an eccentricity of 0.05. The secondary component is a metallic-lined A-type star. The two pairs themselves are separated by 14 arcseconds; one orbit would take at least 55,000 years.[5]
References
edit- ^ a b c d e van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Vizier catalog entry
- ^ a b c Mendoza, E. E. (1974). "Multicolor photometry of metallic-line stars. III. A photometric catalogue". Revista Mexicana de Astronomía y Astrofísica. 1: 175. Bibcode:1974RMxAA...1..175M. Color indices accessed using SIMBAD.
- ^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
- ^ Nicolet, B. (1978). "Catalogue of homogeneous data in the UBV photoelectric photometric system". Astronomy and Astrophysics. 34: 1. Bibcode:1978A&AS...34....1N.
- ^ a b c d e Levato, H.; Malaroda, S.; Morrell, N.; Solivella, G. (1987). "Stellar multiplicity in the Scorpius-Centaurus association". Astrophysical Journal Supplement Series. 64: 487–503. Bibcode:1987ApJS...64..487L. doi:10.1086/191204.
- ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W.
- ^ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
- ^ "* 4 Cen". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 8 February 2018.
- ^ "* 4 Cen A". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 8 February 2018.
- ^ "* 4 Cen B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 8 February 2018.
- ^ Paddock, G. F. (1917). "The Spectroscopic Binary H 4 Centauri". Publications of the Astronomical Society of the Pacific. 29 (167): 56. Bibcode:1917PASP...29...56P. doi:10.1086/122588. S2CID 120812946.