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]
^ abcMendoza, 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.
^Nicolet, B. (1978). "Catalogue of homogeneous data in the UBV photoelectric photometric system". Astronomy and Astrophysics. 34: 1. Bibcode:1978A&AS...34....1N.
^ abcdeLevato, 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.