| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Libra |
| Right ascension | 15h 34m 16.89835s1 |
| Declination | −10° 03′ 05.07536″1 |
| Apparent magnitude (V) | 4.972 |
| Characteristics | |
| Spectral type | K3-III CN23 |
| B−V color index | 1.302±0.0562 |
| Astrometry | |
| Radial velocity (Rv) | −21.8±2.82 km/s |
| Proper motion (μ) | RA: −16.8721 mas/yr Dec.: −17.8201 mas/yr |
| Parallax (π) | 8.7152±0.2628 mas1 |
| Distance | 370 ± 10 ly (115 ± 3 pc) |
| Absolute magnitude (MV) | −0.372 |
| Details | |
| Radius | 25.9±0.41 R☉ |
| Luminosity | 213.6±7.31 L☉ |
| Surface gravity (log g) | 2.304 cgs |
| Temperature | 4,332±341 K |
| Metallicity [Fe/H] | −0.03±0.062 dex |
| Other designations | |
| 42 Lib, CD−23°12458, FK5 3239, GJ 9526, HD 139663, HIP 76742, HR 5824, SAO 1836865 | |
| Database references | |
| SIMBAD | data |
42 Librae is a single6 star located around 3701 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
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 2141 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,332 K.1
References
References
- Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
- McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527.
- "42 Lib". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-07-17.
- Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- Bayer, Johann; Mair, Alexander (1603). Uranometria (in Latin). Excvdit Christophorvs Mangvs. Retrieved 2025-11-10.
- Bode, Johann (1801). Uranometria (in German). Selbstverl. p. 57. Retrieved 2026-01-21.