Beta Librae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Libra |
| Right ascension | 15h 17m 00.41382s |
| Declination | −09° 22′ 58.4919″ |
| Apparent magnitude (V) | 2.61 |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | B8 V |
| U−B color index | −0.359 |
| B−V color index | −0.106 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | −35.2 km/s |
| Proper motion (μ) | RA: −98.10 mas/yr Dec.: −19.65 mas/yr |
| Parallax (π) | 17.62±0.16 mas |
| Distance | 185 ± 2 ly (56.8 ± 0.5 pc) |
| Absolute magnitude (MV) | −1.16 |
| Details | |
| Mass | 3.5+0.3 −0.2 M☉ |
| Radius | 4.77 R☉ |
| Luminosity | 413 L☉ |
| Temperature | 11,900 K |
| Metallicity [Fe/H] | 0.33 dex |
| Rotational velocity (v sin i) | 250 km/s |
| Age | 80+50 −40 Myr |
| Other designations | |
| Zubeneschamali, Kiffa Australis, Lanx Borealis, β Lib, 27 Librae, BD−08°3935, FK5 564, HD 135742, HIP 74785, HR 5685, NSV 7009, SAO 140430 | |
| Database references | |
| SIMBAD | data |
Beta Librae is the brightest star in the zodiac constellation of Libra. It has the proper name Zubeneschamali /zuːˌbɛnɛʃəˈmeɪli/, Beta Librae is its Bayer designation. From parallax measurements taken by the Hipparcos mission, its distance is measured to be 185 light-years (57 parsecs).
The apparent visual magnitude of this star is 2.6. According to Eratosthenes, Beta Librae was observed to be brighter than Antares. Ptolemy, 350 years later, said it was as bright as Antares. The discrepancy may be due to Antares becoming brighter, but this is not known for certain. It could simply be caused by Beta Librae being a variable star, showing a present-day variability of 0.03 of a magnitude.