Star · star

Castor B

Castor B is a star in the constellation Gemini 51.5 ly from Earth. At magnitude 2.9 it is bright enough to see with the naked eye; the light you see left it 52 years ago.

51.5 lybrightness mag 2.85A m

Also catalogued as Alpha Gem · HR 2890 · HD 60178 · Gliese Gl 278B

–

temperature

2.85

apparent magnitude

15.76× ☉

luminosity vs Sun

A m

spectral type

Distance & comparison with our Sun

52 years

at light speed from Earth

–

as hot as the Sun

15.76×

the Sun's light output

1.86

absolute magnitude

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Castor Bstar

Sky regionGeminithis direction

Nearest stars

Bright stars in Gemini

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VISIBLE TO THE NAKED EYE

Brightness mag 2.9To see it no equipment neededLook toward Gemini

Star data from the HYG database v4.2 (Astronexus, CC BY-SA 4.0). Temperature and colour computed by gravityfinder from the B-V colour index; the illustration is generated from that temperature, not a photograph.