Chi Lupi
Star in the constellation Lupus
From Wikipedia, the free encyclopedia
Chi Lupi (Chi Lup, χ Lupi, χ Lup) is a triple star system in the constellation of Lupus. It has an apparent visual magnitude of approximately 3.957.
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Lupus |
| Right ascension | 15h 50m 57.5376s[1] |
| Declination | −33° 37′ 37.796″[1] |
| Apparent magnitude (V) | 3.982±0.018[2] |
| Characteristics | |
| Spectral type | B9.5V + A2Vm[3] + K3V[4] |
| U−B color index | −0.13[5] |
| B−V color index | −0.04[5] |
| R−I color index | −0.07[5] |
| Astrometry | |
| Proper motion (μ) | RA: −5.10 mas/yr[6] Dec.: −24.85 mas/yr[6] |
| Parallax (π) | 16.71±0.27 mas[6] |
| Distance | 203.1±5.5 ly (62.27±1.70 pc)[7] |
| Orbit[7] | |
| Primary | χ Lup A |
| Name | χ Lup B |
| Period (P) | 15.256560(71) days |
| Semi-major axis (a) | 0.2030±0.0029 au |
| Eccentricity (e) | 0.0076±0.0054 |
| Inclination (i) | 110.2±2.1° |
| Longitude of the node (Ω) | −127.1±1.5° |
| Periastron epoch (T) | 2,438,434.4±1.7 JD |
| Argument of periastron (ω) (secondary) | 116±40° |
| Orbit[4] | |
| Primary | χ Lup Ab |
| Name | χ Lup C |
| Period (P) | 9 years |
| Semi-major axis (a) | 7.5 au |
| Details[7] | |
| χ Lup A | |
| Mass | 2.84±0.12 M☉ |
| Radius | 2.85±0.15 R☉ |
| Luminosity | 63[8] L☉ |
| Surface gravity (log g) | 4.08[8] cgs |
| Temperature | 10,200[8] K |
| Rotational velocity (v sin i) | 0[5] km/s |
| Age | 280±30 Myr |
| χ Lup B | |
| Mass | 1.94±0.09 M☉ |
| Radius | 1.75±0.18 R☉ |
| Surface gravity (log g) | 4.2 cgs |
| Temperature | 9,200 K |
| χ Lup C | |
| Mass | 0.79[4] M☉ |
| Other designations | |
| χ Lup, Chi Lupi, Chi Lup, 5 Lupi, 5 Lup, CD−33 10754, CPD−33 3933, FK5 586, GC 21281, HD 141556, HIP 77634, HR 5883, PPM 294334, SAO 207040[1] | |
| Database references | |
| SIMBAD | data |
The primary star in the binary is a mercury-manganese star of spectral type B9.5V; the secondary is a metallic-lined star of type A2Vm.[3] The tertiary is a red dwarf.[4]
This system is a proper motion member of the Upper Scorpius sub-group in the Scorpius–Centaurus OB association, the nearest such co-moving association of massive stars to the Sun.[8] The Upper Scorpius subgroup contains thousands of stars with an average age of 11 million years old at mean distances of 145 parsecs (470 light years).[9]