Alpha Leporis

α Leporis

Location of α Leporis (circled)
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

Alpha Leporis (α Leporis, abbreviated Alpha Lep, α Lep), formally named Arneb /ˈɑːrnɛb/,^[12][13] is the brightest star in the constellation of Lepus.

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]

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]

USS Arneb (AKA-56) was a ship of the United States Navy.