Some of the facts about the Gemini constellation have been known since antiquity. Since it is visible in the sky, its configuration was known to the ancient Greeks and other civilizations.
Facts and Figures
The word Gemini is Latin for twins and is linked to the Greek mythology of Pollux and Castor. It is located in the middle of Taurus (west) and Cancer (east). Lynx and Auriga are to the north. Canis Minor and Monoceros are situated to its south.
There are four bright stars and one near it. Three of the stars there have planets. There is one Messier object. It is best viewed at latitudes +90 degrees and -60 degrees in February at 9:00 PM.
Several facts about the Gemini constellation have been uncovered thanks to modern telescopes and instruments. These include the NGC 2158 and the M35. Another well known feature is the Eskimo nebula (a.k.a. Clownface Nebula).
This is located to the southeast of NGC 2420 open star cluster. To its northeast is NGC 2371. This nebula is right next to the twin configuration. The Medusa nebula is at the southern edge.
The Twin Stars
Its most notable features are the twin stars, Castor and Pollux. Castor is on the right side. Its most visible star is Geminorium, and symbolizes the head and of the second magnitude. Pollux’s magnitude is of the first. Its brightest star represents the head.
The Castor and Pollux myths are jointly known as the Dioscuri. Depictions of the twins vary, depending on the stars used to identity their shapes. Some depict them as moving away from the Milky Way. Other maps show a twin in the galaxy and another one out of it.
The Orion constellation is just outside Gemini, as is Auriga. Pollux is a yellowish orange and classified as a KO spectral type star (similar to Arcturus). Pollux is a solitary star but Castor is actually made up of six stars.
Other facts about the Gemini constellation are the following: the stars in Castor are set in three pairs. Each is categorized as a spectroscopic binary.
To see these stars individually, a spectroscope is required. The most visible are Castor A and Castor B. The former has a magnitude of 2 and the latter 2.9. They are separated by 3 arc seconds.
The major pair is hard to see using ordinary telescopes. Another notable star is Zeta, with a magnitude of 4.4 to 5.2. It is classified as a Cephied star. The M35 is located at Castor’s foot. There are hundreds of stars there. It is 2,800 light years away. The NGC 2158 beside it is 16,000 light years away.
These are just some of the interesting facts about the Gemini constellation. As more powerful telescopes are developed, more information about this cluster of stars will be discovered.