Beta Leporis (β Leporis, abbreviated Beta Lep, β Lep), formally named Nihal /ˈnaɪ.æl/,[11][12] is the second brightest star in the constellation of Lepus.[13]
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Lepus |
Right ascension | 05h 28m 14.72316s[1] |
Declination | −20° 45′ 33.9878″[1] |
Apparent magnitude (V) | 2.84[2] |
Characteristics | |
Spectral type | G5 II[3] |
U−B color index | +0.47[2] |
B−V color index | +0.82[2] |
R−I color index | +0.44[4] |
Astrometry | |
Radial velocity (Rv) | −13.6 ± 0.9[5] 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) |
Absolute magnitude (MV) | −0.65[6] |
Details | |
Mass | 3.5 ± 0.1[7] M☉ |
Radius | 15.9[8] R☉ |
Luminosity | 160±3[9] L☉ |
Surface gravity (log g) | 2.60 ± 0.03[7] cgs |
Temperature | 5,434±38[9] K |
Metallicity [Fe/H] | −0.12±0.06[9] dex |
Rotational velocity (v sin i) | 11[10] km/s |
Age | 240[7] 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 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.[14] In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[15] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[16] included a table of the first two batches of names approved by the WGSN; which included Nihal for this star.
In Chinese, 廁 (Cè), meaning Toilet, refers to an asterism consisting of β Leporis, α Leporis, γ Leporis and δ Leporis.[17] Consequently, the Chinese name for β Leporis itself is 廁二 (Cè èr), "the Second Star of Toilet".[18]
Based on parallax measurements from the Hipparcos astrometry satellite,[19] this star is located about 160 light-years (49 parsecs) from the Earth. It has an apparent visual magnitude of 2.84 and a stellar classification of G5 II. The mass of this star is 3.5 times the mass of the Sun and it is about 240 million years old,[7] 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] The angular diameter of Beta Leporis, after correction for limb darkening, is 3.003±0.066 mas.[20] At the distance to this star, it yield a physical radius of 15.9 times the radius of the Sun.[8]
This is a double star system and may be a binary, whereby the second star has a brightness of 7.34 mag.[21] Using adaptive optics on the AEOS telescope at Haleakala Observatory, the pair was found to be separated by an angle of 2.58 arcseconds at a position angle of 1.4°.[22] Component B has been observed to fluctuate in brightness and is catalogued as suspected variable star NSV 2008.[23]