An Etymological Dictionary of Astronomy and Astrophysics

A variable star in the constellation → Perseus, which was the first eclipsing binary discovered. Its brightness varies between 2.2 and 3.5 magnitudes. Lying at a distance of about 82 → light-years, it consists of at least three components. The brightest component (A)
is of spectral type B8 V, and the second one (B) a K type giant. The components A and B turn around each other with a period of about 68.8 hours.

Etymology (EN): Algol, from Ar. Ra’s al-ghul “the ghoul’s head”.