Alpha Leporis
Brightest star in the constellation Lepus
From Wikipedia, the free encyclopedia
Alpha Leporis (α Leporis, abbreviated Alpha Lep, α Lep), formally named Arneb /ˈɑːrnɛb/,[12][13] is the brightest star in the constellation of Lepus.
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lepus |
| Right ascension | 05h 32m 43.81612s[1] |
| Declination | −17° 49′ 20.2414″[1] |
| Apparent magnitude (V) | 2.589[2] |
| Characteristics | |
| Evolutionary stage | Blue loop (yellow supergiant)[3] |
| Spectral type | F0 Ib[4] |
| U−B color index | +0.386[2] |
| B−V color index | +0.2[5] |
| Astrometry | |
| Radial velocity (Rv) | +23.9[6] km/s |
| Proper motion (μ) | RA: +3.56[1] mas/yr Dec.: +1.18[1] mas/yr |
| Parallax (π) | 1.47±0.14 mas[1] |
| Distance | 2,200 ± 200 ly (680 ± 60 pc)[1] |
| Absolute magnitude (MV) | −5.28[7] |
| Details | |
| Mass | 12–13[8] M☉ |
| Radius | 74[8] – 105+15 −21[9] R☉ |
| Luminosity | 27,000[8] L☉ |
| Surface gravity (log g) | 1.34±0.07[10] cgs |
| Temperature | 7,253 or 7,290[11] K |
| Metallicity [Fe/H] | +0.01–0.06[11] dex |
| Rotational velocity (v sin i) | 13–21[5] km/s |
| Age | 13[10] Myr |
| Other designations | |
| Arneb, 11 Leporis, BD−17°1166, FK5 207, HD 36673, HIP 25985, HR 1865, SAO 150547 | |
| Database references | |
| SIMBAD | data |
Nomenclature
Alpha Leporis is the star's Bayer designation. The traditional name Arneb comes from the Arabic أرنب ’arnab 'hare'[14] ('Lepus' is Latin for hare). 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 Arneb for this star.
In Chinese, 廁 (Cè), meaning Toilet, refers to an asterism consisting of α Leporis, β Leporis, γ Leporis and δ Leporis.[17] Consequently, the Chinese name for α Leporis itself is 廁一 (Cè yī), "the First Star of Toilet".[18]
Properties
Alpha Leporis has a stellar classification of F0 Ib,[4] with the Ib luminosity class indicating that it is a lower luminosity yellow supergiant star. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[19]
This is a massive star with about 12 to 13 times the mass of the Sun[8] and 105 times the Sun's radius.[9] The effective temperature of the outer envelope is about 7,300 K,[11] which gives the star a yellowish-white hue that is typical of F-type stars.[20] It is an estimated 13 million years old.[10] A weak magnetic field was detected around the star.[8]
Arneb is an older, dying star that has already passed through a red supergiant phase and is now contracting and heating up in the latter phases of stellar evolution, in a blue loop.[3]
Namesakes
USS Arneb (AKA-56) was a ship of the United States Navy.