| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 13 53 32.76039 |
| Declination | −35° 39′ 51.3200″ |
| Apparent magnitude (V) | 5.565 (6.27 / 6.38) |
| Characteristics | |
| Spectral type | F4V (F0V + F1V) |
| U−B color index | -0.03 |
| B−V color index | +0.44 |
| Astrometry | |
| Radial velocity (Rv) | -8.00 ± 7.40 km/s |
| Proper motion (μ) | RA: -83.39 mas/yr Dec.: -25.36 mas/yr |
| Parallax (π) | 19.13 ± 0.93 mas |
| Distance | 170 ± 8 ly (52 ± 3 pc) |
| Orbit | |
| Period (P) | 373.0 yr |
| Semi-major axis (a) | 1.519″ |
| Eccentricity (e) | 0.775 |
| Inclination (i) | 74.2° |
| Longitude of the node (Ω) | 112.3° |
| Periastron epoch (T) | B 1958.57 |
| Argument of periastron (ω) (secondary) | 90.7° |
| Details | |
| HD 120987 A | |
| Mass | 1.56 M☉ |
| HD 120987 B | |
| Mass | 1.53 M☉ |
| Other designations | |
| CD−35° 9090, HD 120987, HIP 67819, HR 5222, SAO 204955 | |
| Database references | |
| SIMBAD | data |
HD 120987 (y Centauri or y Cen) is a star system located in the constellation Centaurus. HD 120987 is a quintuple star system located 50 pc (163 light years) from the Sun. The system has an apparent magnitude of 5.565. Based on the system's parallax, it is located some 172 light-years (52 parsecs) away.
HD 120987 appears to be a single F-type star with the spectral classification F4V, but closer inspection reveals it to be two similar F-type main-sequence stars with spectral classifications of F0V and F1V, respectively. The two orbit each other every 373 years, and are separated by 1.519 arcseconds while taking a very eccentric orbit.
References
- ^ van Leeuwen, F.; et al. (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.
- ^ "* y Cen". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 19 July 2017.
- ^ "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Archived from the original on 1 August 2017. Retrieved 19 July 2017.
- ^ Cvetkovic, Z.; Ninkovic, S. (2010). "On the Component Masses of Visual Binaries". Serbian Astronomical Journal. 180 (180): 71. Bibcode:2010SerAJ.180...71C. doi:10.2298/SAJ1080071C.
- ^ Cousins, A. W. J.; Lagerweij, H. C. (1970). "Comparison Stars for Long Period Variables and RY Sagittarii". Monthly Notes of the Astron. Soc. Southern Africa. 29 (7). Bibcode:1970MNSSA..29....7C.
- Kharchenko, N. V.; et al. (2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889. arXiv:0705.0878. Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776. S2CID 119323941.
- ^ Tokovinin, Andrei (2014). "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs". The Astronomical Journal. 147 (4): 87. arXiv:1401.6827. Bibcode:2014AJ....147...87T. doi:10.1088/0004-6256/147/4/87. S2CID 56066740.
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