Alpha Leporis

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

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)	-5.7[7]
Details
Mass	13.9±0.8[8] M☉
Radius	129[9] R☉
Luminosity	30,502±3,111[10] L☉
Surface gravity (log g)	1.34±0.07[8] 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[8] 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

Size comparison of the Sun and numerous stars, the largest of which is Arneb`

This is a massive star with about 14 times the mass of the Sun.^[8] The interferometer-measured angular diameter of this star, after correction for limb darkening, is 1.77 ± 0.09 mas.^[19] At an estimated distance of 2,218 light-years (680 parsecs),^[1] this yields a physical size of about 129 times the radius of the Sun.^[9] 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.^[20] 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.^[21] It is an estimated 13 million years old.^[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.