Kappa Librae
Kappa Librae, Latinized from κ Librae, is the Bayer designation for a star system in the zodiac constellation of Libra. Its apparent visual magnitude is 4.72, so it can be seen with the naked eye. The annual parallax shift of 10.57 mas indicates it is roughly 310 light years away. It is positioned 0.02 degrees south of the ecliptic.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Libra |
| Right ascension | 15h 41m 56.79858s |
| Declination | −19° 40′ 43.7745″ |
| Apparent magnitude (V) | 4.72 |
| Characteristics | |
| Spectral type | K5 III |
| U−B color index | +1.94 |
| B−V color index | +1.58 |
| Astrometry | |
| Radial velocity (Rv) | −4.5±1.5 km/s |
| Proper motion (μ) | RA: −32.06 mas/yr Dec.: −103.15 mas/yr |
| Parallax (π) | 10.57 ± 1.40 mas |
| Distance | approx. 310 ly (approx. 90 pc) |
| Absolute magnitude (MV) | −0.62 |
| Details | |
| Radius | 38 R☉ |
| Luminosity | 296 L☉ |
| Temperature | 3,930 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
The star shows acceleration components in its proper motion, indicating with high probability that it is an astrometric binary. The visible component is an evolved K-type giant star with a stellar classification of K5 III. It is a suspected variable star with a brightness that ranges between 4.70 and 4.75. The measured angular diameter is 3.71±0.10 mas, which, at the estimated distance of Kappa Librae, yields a physical size of about 38 times the radius of the Sun. It radiates 296 times the solar luminosity from its outer atmosphere at an effective temperature of 3,930 K.
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 constellation).