Lions and tigers and – goats? – oh, boy
All kinds of critters roam the night sky including fanciful beasts like dragons, sea monsters, centaurs, a unicorn and a winged horse. Other constellations depict creatures you are likely to encounter on a trip to the local zoo or aquarium. But, did you know that one of the best represented animals is the goat?
In the ancient world, goats were popular livestock. Their hardy constitution and scrappy nature made them the animal of choice to survive rocky, arid and bleak conditions. Goats provided sustenance in the form of meat, milk and cheese. A sea-faring goat is the subject of the zodiacal constellation, Capricornus. But, there are stars named after goats too. To find them we need to turn to the constellation Auriga in the northern sky.
While most star names are Arabic in origin, there is one prominent winter star name that has roots in Latin. It is Capella, the she-goat. Capella, at first magnitude, is the sixth brightest star in the sky and is about 42 light years distant. Also designated Alpha Aurigae, Capella is easy to spot these mid-winter evenings. High above the northeastern horizon in the twilight, it reaches zenith before 10PM.
In ancient mythology, Capella is said to be the goat that nursed baby Jupiter. While roughhousing with the goat, Jupiter broke off one of her horns. He gave the horn the magical power to provide an abundance of whatever the person holding it desired. It became known as the Cornucopia, or the horn of plenty. This seems appropriate as Capella begins its annual appearance in the night sky during the Autumn harvest season.
Next to Capella is a thin isosceles triangle of stars informally known as the ‘the kids’. In ancient times, mariners would keep watch for the October appearance of these stars because they signal the beginning of the Mediterranean storm season. The star at the point of the triangle is of particular interest to astronomers. Designated Epsilon Aurigae and located over 2,000 light years distant, it is sometimes referred to by its Arabic name Almaaz, the he-goat.
Epsilon Aurigae is a binary star consisting of a bright yellow-white supergiant and a dark eclipsing partner that we know little about. During an eclipse, Epsilon Aruigae first dims and then brightens mid-way through leading some astronomers to predict that the occluding body is a star cloaked by a large dusty disc nearly edge-on to our line of sight. Epsilon Aurigae undergoes eclipse every 27 years. The last eclipse occurred during 1982-1984. The current cycle began a couple of months ago and continues into 2011.
In addition to being the home constellation for the goat stars Capella and Almaaz, the constellation Auriga is host to some beautiful open star clusters. All of them can be seen with binoculars or a small telescope.
