For ten points, name this main sequence star whose technical name is Beta Persei.
Astronomically it is regarded as the most unfortunate star in the sky, and its magnitude changes from 2.5 to 3.5 every two days, twenty hours and forty-nine minutes. An eclipsing binary star, its variations were first recorded by Montanari in 1670, but its odd behavior was observed earlier, its name meaning "demon star" in Arabic.  For ten points, name this main sequence star whose technical name is Beta Persei.
Astronomically it is regarded as the most unfortunate star in the sky, and its magnitude changes from 2.5 to 3.5 every two days, twenty hours and forty-nine minutes.
Algol (accept Beta Persei on early buzz)