1 Lupi is a solitary[11] giant star in the southern constellation of Lupus. It has the Bayer designation i Lupi; 1 Lupi is the Flamsteed designation. The apparent visual magnitude is 4.90,[2] which indicates it is faintly visible to the naked eye. Based on parallax measurements, this star is approximately 1,800 light-years from the Sun.[1] It is moving closer to the Earth with a heliocentric radial velocity of −23 km/s.[6]
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Lupus |
Right ascension | 15h 14m 37.32104s[1] |
Declination | −31° 31′ 08.8434″[1] |
Apparent magnitude (V) | 4.90[2] |
Characteristics | |
Spectral type | F1 III[3] or F0 Ib-II[4] |
U−B color index | +0.26[2] |
B−V color index | 0.37[5] |
Astrometry | |
Radial velocity (Rv) | −22.80[6] km/s |
Proper motion (μ) | RA: −9.873[1] mas/yr Dec.: –0.892[1] mas/yr |
Parallax (π) | 1.8055 ± 0.1876 mas[1] |
Distance | approx. 1,800 ly (approx. 550 pc) |
Absolute magnitude (MV) | −3.93[7] |
Details | |
Mass | 6.9±0.1[8] M☉ |
Radius | 41.3+2.2 −1.7[1] R☉ |
Luminosity | 2,900[9] L☉ |
Temperature | 6,867[6] K |
Rotational velocity (v sin i) | 3.9±0.2[5] km/s |
Age | 47.1±3.8[8] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Houk (1978) assigned the spectral classification of this star as F1III,[3] which suggests it is an F-type (yellow-white) star that has evolved away from the main sequence and expanded into a giant. However, Gray et al. (2001) found a class of F0 Ib-II,[4] matching a supergiant/bright giant star. It has a mass around seven times that of the Sun[8] and has expanded to 41[1] times the Sun's radius. The star is radiating 2,900[9] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 6,867 K.[6] The estimated age of the star is around 47 million years.[8]