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.[2] Based on the system's parallax, it is located some 172 light-years (52 parsecs) away.[1]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 13h 53m 32.76039s[1] |
| Declination | −35° 39′ 51.3200″[1] |
| Apparent magnitude (V) | 5.565[2] (6.27 / 6.38)[3] |
| Characteristics | |
| Spectral type | F4V (F0V + F1V)[4] |
| U−B color index | -0.03[5] |
| B−V color index | +0.44[5] |
| Astrometry | |
| Radial velocity (Rv) | -8.00 ± 7.40[6] km/s |
| Proper motion (μ) | RA: -83.39[1] mas/yr Dec.: -25.36[1] mas/yr |
| Parallax (π) | 19.13 ± 0.93 mas[1] |
| Distance | 170 ± 8 ly (52 ± 3 pc) |
| Orbit[3] | |
| 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[7] M☉ |
| HD 120987 B | |
| Mass | 1.53[7] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
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.[4] The two orbit each other every 373 years, and are separated by 1.519 arcseconds while taking a very eccentric orbit.[3]