Phi1 Lupi
Star in the constellation Lupus
From Wikipedia, the free encyclopedia
Phi1 Lupi is a solitary[13] star in the southern constellation of Lupus. It is visible to the naked eye with an apparent visual magnitude of 3.58.[3] Based upon an annual parallax shift of 11.86 mas as seen from Earth, it is located around 275 light years from the Sun. The star is drifting closer with a radial velocity of −29 km/s.[6] It has an absolute magnitude of −1.55.[7]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Lupus[1] |
| Right ascension | 15h 21m 48.36967s[2] |
| Declination | −36° 15′ 40.9525″[2] |
| Apparent magnitude (V) | 3.58[3] |
| Characteristics | |
| Spectral type | K5 III[4] |
| U−B color index | +1.85[3] |
| B−V color index | +1.534±0.005[5] |
| Astrometry | |
| Radial velocity (Rv) | −29.4±0.7[6] km/s |
| Proper motion (μ) | RA: −92.33[2] mas/yr Dec.: −85.67[2] mas/yr |
| Parallax (π) | 11.86±0.16 mas[2] |
| Distance | 275 ± 4 ly (84 ± 1 pc) |
| Absolute magnitude (MV) | −1.55[7] |
| Details | |
| Mass | 1.78[8] M☉ |
| Radius | 40[9] R☉ |
| Luminosity | 1,413[8] L☉ |
| Surface gravity (log g) | 1.93[10] cgs |
| Temperature | 3,800[8] K |
| Metallicity [Fe/H] | −0.40[8] dex |
| Other designations | |
| φ1 Lup, CD−35°10236, FK5 566, HD 136422, HIP 75177, HR 5705, SAO 206552[11] | |
| Database references | |
| SIMBAD | data |
This is an evolved K-type giant star with a stellar classification of K5 III,[4] which means it has used up its core hydrogen and has expanded. At present it has 40 times the radius of the Sun.[9] It is a variable star of unknown type, with an amplitude of 0.008 in visual magnitude and a period of 4.82 days.[14] The star is radiating 1,413 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,800 K.[8]