Lambda Lupi
Triple star system in the constellation Lupus
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Lambda Lupi, Latinized from λ Lupi, is a triple star[11] system in the southern constellation of Lupus. It is visible to the naked eye with a combined apparent visual magnitude of 4.04.[2] Based upon an annual parallax shift of just 4.20[1] mas as seen from Earth, it is located roughly 800 light years from the Sun. The system has a peculiar velocity of 27.4±4.9 km/s relative to its neighbors, making it a candidate runaway star system.[9] It is a member of the Upper Centaurus–Lupus sub-group in the Scorpius–Centaurus OB association.[12]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Lupus |
| Right ascension | 15h 08m 50.61639s[1] |
| Declination | −45° 16′ 47.4950″[1] |
| Apparent magnitude (V) | 4.04[2] (4.43 + 5.23)[3] |
| Characteristics | |
| Spectral type | B3 V[4] (B3 V + B3 V)[5] |
| U−B color index | −0.67[2] |
| B−V color index | −0.18[2] |
| Astrometry | |
| Radial velocity (Rv) | +9.80±1.78[6] km/s |
| Proper motion (μ) | RA: −15.88[1] mas/yr Dec.: −26.80[1] mas/yr |
| Parallax (π) | 4.20±0.66 mas[1] |
| Distance | approx. 800 ly (approx. 240 pc) |
| Absolute magnitude (MV) | −2.75[7] |
| Orbit[8] | |
| Period (P) | 70.8±0.8 yr |
| Semi-major axis (a) | 0.2597±0.0021″ |
| Eccentricity (e) | 0.6283±0.0090 |
| Inclination (i) | 71.59±0.41° |
| Longitude of the node (Ω) | 26.64±0.61° |
| Periastron epoch (T) | 1997.907 ± 0.105 |
| Argument of periastron (ω) (secondary) | 299.9±1.1° |
| Details | |
| λ Lup A | |
| Mass | 8.14[8] M☉ |
| Rotational velocity (v sin i) | 135 km/s |
| Age | 28.1±4.1[9] Myr |
| λ Lup B | |
| Mass | 5.84 M☉ |
| Other designations | |
| λ Lup, CD−44°9889, HD 133955, HIP 74117, HR 5626, SAO 225483, WDS J15088-4517AB[10] | |
| Database references | |
| SIMBAD | data |
The two visible components of this system orbit each other over a period of 70.8 years with a large eccentricity of 0.63.[8] The primary component has a visual magnitude of 4.43, while the secondary is of magnitude 5.23.[3] Both are B-type main sequence stars with a stellar classification of B3 V.[5] One of the pair is itself a double-lined spectroscopic binary, making this a triple star system.[11]