Kappa Librae
Star in the constellation Libra
From Wikipedia, the free encyclopedia
Kappa Librae is a star system in the zodiac constellation of Libra. Its name is a Bayer designation that is Latinized from κ Librae, and abbreviated Kappa Lib or κ Lib. Its apparent visual magnitude is 4.72,[3] so it can be seen with the naked eye. The annual parallax shift of 10.57 mas[2] indicates it is roughly 310 light years away. It is positioned 0.02 degrees south of the ecliptic.
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Libra[1] |
| Right ascension | 15h 41m 56.79858s[2] |
| Declination | −19° 40′ 43.7745″[2] |
| Apparent magnitude (V) | 4.72[3] |
| Characteristics | |
| Spectral type | K5 III[4] |
| U−B color index | +1.94[3] |
| B−V color index | +1.58[3] |
| Astrometry | |
| Radial velocity (Rv) | −4.5±1.5[5] km/s |
| Proper motion (μ) | RA: −32.06[2] mas/yr Dec.: −103.15[2] mas/yr |
| Parallax (π) | 10.57±1.40 mas[2] |
| Distance | approx. 310 ly (approx. 90 pc) |
| Absolute magnitude (MV) | −0.62[1] |
| Details | |
| Mass | 1.6[6] M☉ |
| Radius | 38[7] R☉ |
| Luminosity | 388[8] L☉ |
| Surface gravity (log g) | 1.35[6] cgs |
| Temperature | 3,875[7] K |
| Metallicity [Fe/H] | −0.39[6] dex |
| Other designations | |
| κ Lib, 43 Lib, BD−19°4188, FK5 1413, HD 139997, HIP 76880, HR 5838, SAO 159442[9] | |
| Database references | |
| SIMBAD | data |
The star shows acceleration components in its proper motion, indicating with high probability that it is an astrometric binary.[10] The visible component is an evolved K-type giant star with a stellar classification of K5 III.[4] It is a suspected variable star with a brightness that ranges between 4.70 and 4.75.[11] Kappa Librae is 38 times larger than the Sun,[7] and is radating 388 times the solar luminosity[8] from its outer atmosphere at an effective temperature of 3,875 K.[7]
In Chinese astronomy, Kappa Librae is called 日, Pinyin: Rì, meaning Sun, because this star is marking itself and stand alone in Sun asterism, Room mansion (see: Chinese constellations).[12]