Observatory

Mythology

In most mythologies, the constellation most commonly known as Gemini is seen as twins. The most renowned tale originated in ancient Greece. Queen Leda was impregnated, on the same night, by two different men and nine months later gave birth to the twins Castor and Pollux. Castor was the son of Leda’s husband, King Tyndarus, while Pollux was the son of Zeus, who had cleverly disguised himself as a swan nine months earlier (Lynch 75).

The two were grew to be inseparable, both twins and the closest of friends. In their young adulthood, they got themselves into a skirmish with two other men. Although they were victorious, Castor suffered a mortal wound. Pollux, being half god, was himself an immortal and he could not bear to live without his brother by his side. He convinced Zeus to allow them to live together amongst the stars (Lynch 76).

Apart from the Greek myth, their significance stretched to many cultures and even religions. The Jews considered them to be of the Benjamin brethren, while the Christians either Saint James or Adam and Eve. They have also been represented as peacocks by the medieval Arabians (later as twins), two sprouting plants by the Egyptians, and a pile of bricks in some Roman references. The Chinese depicted them as first the ape (of an older Chinese zodiac) and then as Yin Yang and Jidim (Allen 222-29).

Gemini is also considered a good luck sign to sailors. Being the zodiac sign for the end of May and beginning of June means that the constellation is in the sun during this period of the year. When Gemini rises shortly before sunrise the warm spring and summer are approaching and the unpleasant sailing/boating weather is finally nearing an end (for those in the Northern Hemisphere).

Physical Properties

The major stars which constitute Gemini include but are not limited to: Pollux, Castor, Mebsuta, Wasat, Mekbuda, Alhena, and Alzirr. Some prominent nearby objects are the Eskimo Nebula (NGC2392), and the open cluster M35 (Lynch 77).

The star Pollux is the brightest within the constellation; with a distance of 35 light years from the Sun and a magnitude of +1.2 (Mayall 104). Pollux has a singular giant planet in orbit which is over two times as large as Jupiter (the largest in the Solar system) and is slightly farther from its own mother star than is Mars from the Sun. Aside from Pollux, there are two other stars in Gemini with planets, these being HR2877 and HR50554 (Kaler).

The other primary star of Gemini, Castor, is actually made up of a sextuple – three pairs of stars (Kaler). Castor is farther than Pollux from the Sun with an approximate distance of 45 light years, with a magnitude of +2.0 (Mayall 104). Curiously, Castor was named α in the constellation (typically the label is placed on the brightest star).

The Eskimo nebula, so named for its appearance – a face surrounded by a thick circular fur hood, is at a distance of about 3,000 light years with a magnitude of +8.5. Eskimo Nebula’s shape was created by high speed winds blowing matter outward from the central dying star.

At a distance of 2,800 light years and a magnitude of +5.3 is the M35 open star cluster. This cluster contains over 500 stars and has a diameter of about 24 light years (Frommert).

by: Anna Goren

revisited by: Andrew Shough

Sources

http://www.daviddarling.info/encyclopedia/E/Eskimo_Nebula.html

http://stars.astro.illinois.edu/sow/castor.html

http://messier.seds.org/m/m035.html

http://www.hawastsoc.org/deepsky/gem/index.html

Mayall, Newton R., Margaret Mayall, and Jerome Wyckoff. The Sky Observer's Guide. New York: St Martin's Press, 2002. 104-06. Print.

Lynch, Mike. Michigan Starwatch. Stillwater, MN: Voyageur Press Inc., 2005. 74-77. Print.

Allen, Richard H. Star Names Their Lore and Meaning. New York: Dover Publications Inc., 1963. 222-37. Print.