1. IN THE CONSTELLATION GEMINI – THE TWINS
CASTOR AND POLLUX
IN THE CONSTELLATION GEMINI –
THE TWINS
Castor and Pollux are well placed in the evening sky from late November through May.

2. Gemini
The single point of light we call Castor appears as one of two bright stars in the constellation Gemini the Twins. It appears as a prominent white star, noticeable for its nearness to its brother star, Pollux in Gemini. No other two such bright stars appear so close together on our sky’s dome.
Castor and Pollux are sometimes called the “twin” stars, but you can tell them apart easily. The brighter and more golden star is Pollux. The fainter, whiter star is Castor.
These two stars of nearly equal brightness in Earth’s sky are not really related in space. At 34 light-years, Pollux is closer than Castor (52 light-years). Thus Pollux and Castor aren’t gravitationally bound, but only near each other along our line of sight. But their proximity in our sky makes them easy to spot.

3. Castor Through a Telescope
Castor through a telescope appears as two bright stars, but it is really 3 double stars – 6 stars in one!
The mass of these 6 stars together is roughly 6 times that of our Sun!

4. The Mythology of Castor & Pollux
In Greek mythology Pollux is immortal, the son of Zeus, and Castor is mortal, the son of King Tyndareus of Sparta. Thus they were really half-brothers rather than true twins, with a common mother in Queen Leda. Their sister is Helen of Troy. Castor and Pollux later were among the Argonauts who sailed with Jason in search of the Golden Fleece, and due to their mutual devotion, Zeus placed them both in the heavens on their death, so that they could remain together forever.