Alphekka (Alpha Coronae Borealis)
Corona Borealis and environs. Map © 2003 Torsten Bronger.
Alphekka (Alpha Coronae Borealis), also known as Gemma, is the brightest star in the constellation Corona Borealis. Its Arabic name (alternatively spelled "Alphecca"), meaning "break," refers to the broken circlet of stars that makes up the Northern Crown.
Alphekka is an Algol star: the bright naked-eye star has a much fainter, Sun-like (G5) companion, that produces a barely discernible eclipse of the primary every 17.4 days. Alphekka is also a part of the Ursa Major Moving Cluster.
|spectral type||A0V + G5V|
|surface temperature||9,500 K|
|distance||75 light-years (23 pc)|
|position||R.A. 15h 34m 41.3s,
Dec. +26° 42' 53"
|other designations||Alphecca, Gnosia, Ashtaroth,
5 CrB, HR 5793, BD +27°2512,
HD 139006, GCTP 3519.00,
SAO 83893, FK5 578, HIP 76267