Arneb (Alpha Leporis)
Arneb (Alpha Leporis) is a star in the constellation Lepus, magnitude 2.6.
A yellow-white supergiant that has already been red — the bright heart of the Hare.
Arneb has lived fast. With 12 or 13 times the Sun’s mass, it is only about 13 million years old, yet it has already burned through the hydrogen in its core, ballooned into a red supergiant, and is now shrinking and heating up again — a late-life detour astronomers call a blue loop.
Even after shrinking it is huge, about 105 times the Sun’s width: set in the Sun’s place, its surface would reach beyond the orbit of Mercury. At around 7,300 K, that surface glows the yellowish white typical of an F-type star.
The name is simply Arabic for “hare”, matching the Latin Lepus.
Arneb (Alpha Leporis) is 2,200 light-years away: the light we see from it set off around 180 BC, 250 years before Vesuvius buried Pompeii.
Did you know?
- The First Star of Toilet. Chinese astronomers grouped Arneb with three other stars of the Hare as Cè, the Toilet. Arneb is “the First Star of Toilet”.
- A yardstick star. Since 1943 Arneb’s spectrum has been one of the fixed anchor points astronomers use when sorting other stars by type.
- USS Arneb. The US Navy named an attack cargo ship after the star: USS Arneb (AKA-56).
A yellowish-white star of magnitude 2.6, the brightest in Lepus, the Hare crouching beneath Orion’s feet. Look about 10 degrees south of Rigel, and compare Arneb’s creamy tint with Rigel’s blue-white.
When and where to see it
It is best placed in the evening sky around January, when it crosses the meridian at about 10 pm local time (around midnight in December). It can be seen from everywhere south of 72°N and never sets south of 72°S.
At its highest it stands 22° up from 50°N, 37° up from 35°N, 72° up from the equator, 73° up from 35°S.
Facts
- Type
- Star
- Constellation
- Lepus
- Designations
- Alpha Leporis, α Lep, 11 Lep, HR 1865, HD 36673, HIP 25985
- Magnitude
- 2.6
- Position
- RA 5h 32.7m, Dec −17° 49′ (J2000)
- Spectral type
- F0Ib
- Colour
- yellow-white (B−V 0.20)
- Distance
- 2,200 light-years
- Discovered
- Known since antiquity
Open AstroPilot to see when Arneb (Alpha Leporis) is highest tonight from your location, how easy it is with your telescope or binoculars, and an eyepiece view.