2 Lupi

2 Lupi is a single^[8] star in the southern constellation of Lupus,^[7] located 326 light-years away from the Sun.^[1] It has the Bayer designation f Lupi; 2 Lupi is the Flamsteed designation. This object 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]

2 Lupi

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
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]