Gemma

History

Gemma (Latin: Jewel) is the designation of the star Alpha Coronae Borealis. This star, which is sometimes called also Alphekka or Alphecca (from the Arabic al-fakkah, "the broken" (ring of stars), from فكّ fakk "unsealed"), is 80 light years away from the earth and belongs to the spectral type A0V+G5V.

Description

Gemma is an eclipsing binary star similar to Algol (Beta Persei). Gemma varies with a period of 17.36 days between a brightness of +2.16 and +2.30, which is hardly noticeable to the unaided eye.

Coordinates (epoch 2000.0)

• Right Ascension: 15h34m41.30s
• Declination: +26°42'53.0"