42 Librae
Star in the constellation Libra
From Wikipedia, the free encyclopedia
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]
| 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 |
The Bayer designation Chi Librae has been associated with this star, despite Johann Bayer not marking it as such in his Uranometria.[7] Bode assigned the designation χ Librae to this star in his Uranographia.[8] The designation is no longer in use.
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]