Lepus, the hare, is the last of the four winter constellations in the Orion story. Like its wild namesake, the hare keeps a low profile, and can be a little tricky to find at first, hiding in the celestial undergrowth at Orion's feet.
The brightest (alpha) star in the constellation is Arneb, Arabic for hare. It is an F0I yellow/white supergiant at least 75 times larger than our Sun, and over 10,000 times brighter. It is about 13 million years old and nearing the end of its stellar life. Because of its size it will end its life in a supernova explosion, with catastrophic consequences for any nearby star systems. Fortunately for us we are over 2,000 light years away. Arneb shines in our sky with an apparent magnitude of 2.58.
At magnitude 2.81, the second brightest star, Beta Leporis, is named Nihal. According to R.H. Allen the four brightest stars in Lepus were known to the Arabs as "Al Nihal", the Thirst-slaking Camels, making their way to the "celestial river" of the Milky Way. Nihal is a G3III yellow giant, about 160 light years away.
The star designated R Leporis (HD 31996) has been named Hind's Crimson Star, after the man who first catalogued its extreme variability and deep red colour. Over the course of 14 months the star changes magnitude from 5.5 to 11.7, glowing with a particularly deep red hue. It is classified as a C6 red supergiant carbon star, right off the scale at the red (M) end of the H-R diagram. It is the abundance of carbon that enriches the star's red colour. It has a diameter 500 times greater than our Sun, and it is located about 1,360 light years away.
There are five stars in Lepus that have been found to support planetary systems. All the stars are beyond naked eye visibility, and all the planets are gas giants. With one star however, HD 31527, they are relatively small gas giants, some may call them super earths, 12 - 16 times the size of our home planet. What's more, one of these planets orbits in the habitable zone of the star, where liquid water could exist. The three planet system is 125 light years away. For more information on these and other extrasolar planets, visit NASA's New Worlds Atlas, and The Open Exoplanets Catalogue.
Acquirers of new telescopes invariably turn their new scopes first to the 110 Messier objects, the biggest and brightest of the deep sky wonders and the first to be catalogued, thanks to the efforts of famed French astronomer, Charles Messier. Back in the eighteenth century, Messier used a crude four inch refractor telescope to hunt for "fuzzy stars" that might be comets. He discovered thirteen comets over the years, but he also came across many objects that looked like comets, but did not change position as comets did, and he made a list of them. Messier had no idea what these objects were, and simply termed them nebulae, Latin for cloud, or mist. His list was ultimately published as the famous Messier Catalogue in 1771, and is still used today by astronomers worldwide. The 110 Messier objects were eventually identified as star clusters, true nebulae, and galaxies.
Lepus contains one Messier object, the globular cluster M79 (NGC 1904). At magnitude 7.7 it is easily accessible with binoculars or a small telescope. It is about 118 light years across, and about 40,100 light years away.
Globular clusters like M79 are mini-galaxies, usually containing a few hundred thousand stars. They are gravitationally bound satellites of the much larger, true galaxies that contain hundreds of billions of stars. Globular clusters do not follow the rest of the stars in the spiral arms of a galaxy, but orbit the centre of the galaxy in wide ranging elliptical orbits, surrounding the galaxy in a spherical cloud, an area referred to as the halo.
There appear to be a good number of globular clusters surrounding all large galaxies. There are close to 200 globular clusters surrounding our Milky Way galaxy. The closest is about 8,000 light years away, and the farthest about 180,000 light years. Globular clusters are compact spheres of stars, averaging only a few dozen light years in diameter, in which most of the stars are no more than a light year apart. The stars in the centre of a globular cluster would be a thousand times closer, or about half the width of our solar system.
Globular clusters are the elders of the galactic community, composed of stars almost as old as the Universe itself, that have long ago consumed any gas or dust in their vicinity. This lack of building materials, along with the disrupting tidal influences of so many stars so close together would appear to make globular clusters unlikely venues for planet formation. If a planet such as Earth could survive inside a globular cluster, the sky would be overflowing with suns, and there would be no such thing as "night", as imagined in the famous Isaac Asimov tale Nightfall.
It's called a Planetary Nebula, but there are no planets in sight. Through a small telescope it can look a little like a planet, but through the eyes of Hubble we see its true nature, in living colour. IC 418, commonly known as The Spirograph Nebula, is a bubble of ejected gas being shed by the dying star at its centre. At magnitude 9.6 it lies about 2,000 light years away.
|Winter: Orion Canis Major Canis Minor Monoceros Lepus Eridanus Taurus Auriga Camelopardalis Lynx Gemini Cancer|
|Spring: Hydra Sextans Crater Corvus Leo Leo Minor Ursa Major Ursa Minor Canes Venatici Coma Berenices Virgo Bootes|
|Summer: Draco Corona Borealis Hercules Ophiuchus Serpens Libra Scorpius Sagittarius Scutum Aquila Sagitta Vulpecula Lyra Cygnus|
|Autumn: Andromeda Perseus Pegasus Cassiopeia Cepheus Cetus Lacerta Delphinus Equuleus Capricornus Aquarius Pisces Aries Triangulum|
|Southern Skies: Centaurus Crux Lupus Corona Australis Piscis Australis Sculptor Tucana Fornax Dorado Columba Puppis Carina Vela|