The name “Lepus” derives from the Latin word for “hare”, and although there are no myths associated with this constellation, it is often represented on old charts as a hare being chased by the dogs of Orion, represented by the constellations Canis Major and Canis Minor. It can be seen from latitudes between +63 and -90 degrees, and is the 51st largest constellation.
Lepus contains only one Messier object, the globular cluster M79 (NGC 1904), and one star with confirmed planets. The constellation is also home to several notable stars, among which is R Leporis, the reddest star known, the irregular galaxy NGC 1821, and one of the most intricately-shaped planetary nebulae known, the Spirograph Nebula (IC 418). No meteor showers are associated with Lepus.
Orion Family of Constellations
Lepus borders on the constellations Caelum, Canis Major, Columba, Eridanus, Monoceros and Orion, and along with Canis Major, Canis Minor, Monoceros and Orion, it forms the Orion family of constellations.
– Alpha Leporis (Arneb), the most luminous star in Lepus (2.589 mag), is located about 2,200 light years away, and derives its name from the Arabic word “arnab” meaning “the hare”. Arneb is estimated to be only 13 million years old, but is still considered extremely ancient for a F0 Ib class star, having almost consumed all its fuel. The star is now heating up as it collapses to end its life in a supernova explosion, and is about 129 times as big as the Sun, and shines 32,000 times more brightly.
– Epsilon Leporis; Lepus has no shortage of spectacular stars, and Epsilon Leporis, a K4 III orange giant about 213 light years away, is clearly spectacular. With an apparent magnitude of 3.166, it has 1.7 times the mass of the Sun, but is 40 times bigger, and shines about 327 times brighter.Epsilon Leporis is a relatively young star; it is estimated be only about 1.7 billion years old.
– Zeta Leporis is located about 70 light years away, and is not much bigger or heavier than the Sun. It has only 1.46 times the mass of the Sun, and shines 14 times as brightly, but what makes it special is its classification, A2 IV-V(n). The (n) denotes the fact that it is a very fast rotator, with a rotational speed of 245 kilometres per second, which is close to the point at which a star’s gravity cannot hold itself together to counteract the centrifugal forces created by its angular velocity. In fact, this star spins so fast that the absorption lines in its spectrum are widened by the Doppler effect to the point where they take on a nebulous appearance. Zeta Leporis is also the only other star known to be surrounded by a massive asteroid belt, which was confirmed to surround the star in 2001. Zeta Leporis has an apparent visual magnitude of 3.524, and is estimated to be only about 230 million years old.
– R Leporis (Hind’s Crimson Star), a carbon star with the classification C7,6e(N6e), is perhaps better known as Hind’s Crimson Star, and it is arguably the most famous variable star in the entire sky. It is classified as a long-period Mira variable star with two distinct periods of variability; one being a period of 418 to 441 days, and another that spans roughly 40 years. During these periods the star can vary in magnitude from 5.5 to as dim as 11.7. Hind’s Crimson Star is about 1,300 light years away, and when its discoverer, J.R Hind, first observed it, he described it as being like “….a drop of blood on a black field.” Apart from resembling a drop of blood, the star is about 500 times as big as the Sun, and shines between 5,000 and 7,000 times as brightly. Look for Hind’s Crimson Star close to the border with Eridanus, where it is the reddest star in the sky when it is at its dimmest, which occurs about every 14.5 months.
Deep Sky Objects
Spirograph Nebula (IC 418); there are no simple planetary nebulae; all have complex structures that are in most cases still awaiting explanation, but this nebula, IC 418, can only be described as “physics become art”. The intricate arrangement of shells-within-shells of gas and dust seems like the shells were traced with a spirograph, hence the name, the Spirograph Nebula. There is as yet no clear explanation of the mechanisms and forces at work within the nebula, and as a result, it is probably the most intensely studied planetary nebula of all. The Spirograph Nebula is located about 1,100 light years away, and has an apparent magnitude of 9.6.
Messier 79 (M79, NGC 1904); located about 41,000 light years away, this globular cluster is thought to have originated outside of the Milky Way, in the Canis Major Dwarf Galaxy to be precise. The diminutive Canis Major Dwarf Galaxy is engaged in a gravitational tug-of-war with the Milky Way, and it seems highly unlikely that the smaller galaxy will escape being destroyed by the encounter.