42 Librae

42 Librae is a single^[6] star located around 370^[1] light years distant from the Sun in the southern zodiac constellation of Libra.^[5] It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.97.^[2] This object is drifting closer to the Earth with a heliocentric radial velocity of −22 km/s.^[2]

42 Librae

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Libra
Right ascension	15h 34m 16.89835s[1]
Declination	−10° 03′ 05.07536″[1]
Apparent magnitude (V)	4.97[2]
Characteristics
Spectral type	K3-III CN2[3]
B−V color index	1.302±0.056[2]
Astrometry
Radial velocity (Rv)	−21.8±2.8[2] km/s
Proper motion (μ)	RA: −16.872[1] mas/yr Dec.: −17.820[1] mas/yr
Parallax (π)	8.7152±0.2628 mas[1]
Distance	370 ± 10 ly (115 ± 3 pc)
Absolute magnitude (MV)	−0.37[2]
Details
Radius	25.9±0.4[1] R☉
Luminosity	213.6±7.3[1] L☉
Surface gravity (log g)	2.30[4] cgs
Temperature	4,332±34[1] K
Metallicity [Fe/H]	−0.03±0.06[2] dex
Other designations
42 Lib, CD−23°12458, FK5 3239, GJ 9526, HD 139663, HIP 76742, HR 5824, SAO 183686[5]
Database references
SIMBAD	data

This is an aging giant star with a stellar classification of K3-III CN2,^[3] where the suffix notation indicates this is a strong CN star with a high overabundance of cyanogen in its spectrum. Having exhausted the supply of hydrogen at its core, this star has expanded to 26 times the Sun's radius.^[1] Within the margin of error it has near-solar abundances of iron,^[2] suggesting a Sun–like metallicity. The star is radiating 214^[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,332 K.^[1]