Star profile
Castor
Alpha Geminorum · Gemini
What is Castor
Castor shines in Gemini just 50.9 light-years away, close enough to count as a cosmic neighbour. It is a white class-A star that looks like a single point to the naked eye, though telescopes reveal a tangled stellar family hiding behind it. To the ancient Greeks it stood beside Pollux, the divine twins of Leda, horsemen and patrons of sailors who prayed for clear weather.
Where it is and when to see it
Castor lies in the northern celestial hemisphere. It is visible to the naked eye under a dark sky. Its best month of the year is January: the Sun sits at the opposite point of the sky and the star culminates around midnight. How high it climbs above the horizon depends on the latitude you watch from.
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The signature wall
Stelvia's sky works like a signature wall: anyone can leave their name and a message on a real star, and that signature goes up on the map for everyone to read. Signing is free.
A signature without a lock can be replaced by someone else's. The lock makes the signature permanent and lets you choose a symbolic name for the star, always shown next to the star's catalogue identifier. How the lock works
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A public signature from a real person. The chosen name is a symbolic denomination within Stelvia, with no official standing or IAU recognition: the sky is not for sale and belongs to no one.
Astronomical data for Castor
- Constellation
- Gemini
- Apparent magnitude
- 1.58
- Distance
- 50.9 light years
- Coordinates (J2000)
- RA 113.650° · Dec 31.888°
- Catalogue
- HIP 36850 · HD 60179
A symbolic commemorative gift: neither the signature nor the chosen name implies ownership of the star or recognition by the IAU.
Other stars in Gemini
Gemini has 74 stars in Stelvia's catalogue. Here are a few of them.
- PolluxBeta Geminorum1.16
- AlhenaGamma Geminorum1.93
- Castor BAlpha Geminorum2.85
- TejatMu Geminorum2.87
- MebsutaEpsilon Geminorum3.06
- PropusEta Geminorum3.31
- AlzirrXi Geminorum3.35
- WasatDelta Geminorum3.50