2 Lupi
Star in the constellation Lupus
From Wikipedia, the free encyclopedia
2 Lupi, also known by its Bayer designation f Lupi, is a solitary[8]star in the southern constellation of Lupus,[7] situated approximately 326 light-years away from the Sun.[1] It has the Bayer designation f Lupi; 2 Lupi is the Flamsteed designation. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.33.[2] It is moving closer to the Earth with a heliocentric radial velocity of −3 km/s.[6]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lupus |
| Right ascension | 15h 17m 49.83809s[1] |
| Declination | −30° 08′ 55.2165″[1] |
| Apparent magnitude (V) | 4.33[2] |
| Characteristics | |
| Evolutionary stage | giant |
| Spectral type | K0 IIIa CH-1[3] |
| B−V color index | 1.100±0.004[4] |
| Variable type | none[5] |
| Astrometry | |
| Radial velocity (Rv) | −2.91±0.15[6] km/s |
| Proper motion (μ) | RA: −10.16[1] mas/yr Dec.: −3.66[1] mas/yr |
| Parallax (π) | 10.01±0.21 mas[1] |
| Distance | 326 ± 7 ly (100 ± 2 pc) |
| Absolute magnitude (MV) | −0.65[4] |
| Details | |
| Radius | 11.0+0.7 −0.8[6] R☉ |
| Luminosity | 65.6±0.8[6] L☉ |
| Surface gravity (log g) | 2.84[2] cgs |
| Temperature | 4,953+197 −148[6] K |
| Metallicity [Fe/H] | 0.11[2] dex |
| Other designations | |
| f Lupi, 2 Lup, NSV 7012, CD−29°11630, FK5 3207, HD 135758, HIP 74857, HR 5686, SAO 183346[7] | |
| Database references | |
| SIMBAD | data |
This is an aging giant star with a stellar classification of K0 IIIa CH-1.[3] The suffix notation indicates abnormally weak lines of carbyne. Having exhausted the hydrogen at its core, the star evolved away from the main sequence by expanding to 11[6] times the Sun's radius. The star is radiating 65.6[6] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,953 K.[6]
2 Lupi is also moving steadily toward our solar system at a rate of roughly –3 km/s. This slow approach is observable through its measured radial velocity.[9]