What is the constellation Gemini?
The Twins (Gemini) is a zodiacal constellation. Its brightest stars are Beaver (α), of second magnitude, and Pollux (β), first. Gemini It can be seen in the winter sky, between Taurus presenter and the faint constellation Cancer in the east, with Auriga and Lynx in the north and Monoceros and Canis Minor in the south.
Gemini main stars
Beaver (α Geminorum)
Beaver It is a white giant star. With a magnitude of 1.58, it is not the brightest in the constellation (this place corresponds to Pollux) and its designation «α» is due to its position, which is the furthest north of the Twins. It is the 24th brightest star in the sky.
Castor is in fact a multiple system. To a first approximation it is a double star.
Castor-A is a white star of magnitude 1.98. Castor-B is also white, magnitude 2.88. They circle around each other following an eccentric orbit in 400 years.
Each of these two stars is also double. Castor-A is composed of two similar stars that orbit in 9.2 days at a distance of 0.04 au. The two stars of Castor-B complete one revolution in just 2.9 days.
About 1,000 au from this double Castor-C orbit pair, of the ninth magnitude, which is also double. In total, Castor is a sixfold star system.
Pollux (β Geminorum)
The brightest star in the constellation is Pollux (β Geminorum), magnitude 1.16, the 17th brightest star in the sky. It is an orange giant, distant about 34 light-years (close supply of our solar system, then), about ten times larger than the Sun.
Extrasolar Planets
Two stars have extrasolar planets: HD 49674with a planet 0.12 times the mass of Jupiter, orbiting at 0.0568 au in 4,948 days, and HD 50,5544.9 times more massive than Jupiter, at 2.38 AU with a revolution of 1,279 days.
Gemini Deep Sky Objects
In the Gemini constellation There is the diffuse nebula IC 443, the open clusters M35 and NGC 2420 and the planetary nebulae NGC 2,371, NGC 2392 and PLN205-14.1.
Gemini History
For the Greeks, the Gemini constellation represented Castor and Pollux , the twin brothers of Helen of Troy. The Romans saw Romulus and Remus.
NASA’s Gemini space exploration program during the 1960s was named after this constellation.