| |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lepus |
| Right ascension | 05h28m 14.72316s[1] |
| Declination | −20° 45′ 33.9878″[1] |
| Apparent magnitude (V) | 2.813[2] |
| Characteristics | |
| Spectral type | G5 II[3] |
| U−B color index | +0.47[4] |
| B−V color index | +0.808[2] |
| R−I color index | +0.44[5] |
| Astrometry | |
| Radial velocity (Rv) | −13.6 ± 0.9[6] km/s |
| Proper motion (μ) | RA: −5.02[1] mas/yr Dec.: −85.92[1] mas/yr |
| Parallax (π) | 20.34 ± 0.18 mas[1] |
| Distance | 160 ± 1 ly (49.2 ± 0.4 pc)[1] |
| Absolute magnitude (MV) | −0.65[7] |
| Details | |
| Mass | 2.948±0.031[2] M☉ |
| Radius | 12.573±0.153[2] R☉ |
| Luminosity | 171[8] L☉ |
| Surface gravity (log g) | 2.88[2] cgs |
| Temperature | 5,398[2] K |
| Metallicity [Fe/H] | −0.08±0.02[2] dex |
| Rotational velocity (v sin i) | 11[9] km/s |
| Age | 391±11[2] Myr |
| Other designations | |
Nihal, β Lep, Beta Leporis, Beta Lep, 9 Leporis, 9 Lep, BD−20 1096, FK5 204, GC 6762, HD 36079, HIP 25606, HR 1829, PPM 248938, SAO 170457, WDS 05282-2046A.[3] | |
| Database references | |
| SIMBAD | data |
Beta Leporis (β Leporis, abbreviated Beta Lep, β Lep), formally named Nihal /ˈnaɪ.æl/,[10][11] is the second brightest star in the constellationofLepus.[12]
Beta Leporis is the star's Bayer designation. It is also known by the traditional named Nihal, Arabic for "quenching their thirst". The occasional spelling Nibal appears to be due to a misreading.[13] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[14] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[15] included a table of the first two batches of names approved by the WGSN; which included Nihal for this star.
InChinese, 廁 (Cè), meaning Toilet, refers to an asterism consisting of β Leporis, α Leporis, γ Leporis and δ Leporis.[16] Consequently, the Chinese name for β Leporis itself is 廁二 (Cè èr), "the Second Star of Toilet".[17]
Based on parallax measurements from the Hipparcos astrometry satellite,[18] this star is located about 160 light-years (49parsecs) from the Earth. It has an apparent visual magnitude of 2.81[2] and a stellar classification of G5 II.[3] The mass of this star is 3 times the mass of the Sun and it is about 390 million years old,[2] which is the sufficient time for a star this massive to consume the hydrogen at its core and evolve away from the main sequence, becoming a G-type bright giant.[3] Currently, it has expanded to 12.6 times the Sun's size[2] and is emitting 171 times its luminosity.[8]
This is a double star system and may be a binary, whereby the second star has a brightness of 7.34 mag.[19] Using adaptive optics on the AEOS telescopeatHaleakala Observatory, the pair was found to be separated by an angle of 2.58 arcseconds at a position angle of 1.4°.[20] Component B has been observed to fluctuate in brightness and is catalogued as suspected variable star NSV 2008.[21]
