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Star profile

Alphecca

Alpha Coronae Borealis · Corona Borealis

Variable star
3D likeness based on its real data · class A · ~8,500 K

What is Alphecca

Alphecca, also called Gemma, is the jewel set into the Northern Crown, that small semicircular diadem painted into the northern sky by the Greeks and Romans. It shines with white A-type light, faintly variable because an unseen companion eclipses it briefly every seventeen days or so. At only 75 light-years away, its present glow set out around 1951, when the early jet age was just beginning to compress the world.

Where it is and when to see it

Alphecca lies in the northern celestial hemisphere. It is visible to the naked eye under a dark sky. Its best month of the year is May, when it culminates around midnight.

  • From London it culminates about 65° above the horizon.
  • From New York it culminates about 76° above the horizon.
  • From Sydney it culminates about 29° above the horizon.

It can be seen from anywhere north of 63° S.

It is the brightest of the 26 stars of Corona Borealis in our catalogue, which makes it the best starting point for finding your way around the constellation.

The light you see today left it about 75 years ago.

Find it on the sky map

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Leave your signature on Alphecca

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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 Alphecca

Constellation
Corona Borealis
Apparent magnitude
2.22
Distance
75.1 light years
Coordinates (J2000)
RA 233.672° · Dec 26.715°
Catalogue
HIP 76267 · HD 139006

A symbolic commemorative gift: neither the signature nor the chosen name implies ownership of the star or recognition by the IAU.

Other stars in Corona Borealis

Corona Borealis has 26 stars in Stelvia's catalogue. Here are a few of them.

See all 26 stars in Corona Borealis