Algol
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Algol, designated Beta Persei, known colloquially as the Demon Star, is a bright multiple star in the constellation of Perseus and one of the first non-nova variable stars to be discovered.
The Algol system on 12 August 2009. This is a CHARA interferometer image with 1/2-milliarcsecond resolution in the near-infrared H-band. The elongated appearance of Algol Aa2 (labelled B) and the round appearance of Algol Aa1 (labelled A) are real, but the form of Algol Ab (labelled C) is an artifact.
Algol is a bright star in the constellation of Perseus (upper right).
The constellation Perseus and Algol, the Bright Star in the Gorgon's head (Johannes Hevelius, Uranographia, 1690)
Binary star
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A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars are among the most important objects in astrophysics because
Algol
…doppler shifts in the spectrum of Algol, inferring variations in the radial velocity of this binary system. Thus, Algol became one of the first known spectroscopic binaries. Joel Stebbins at the University of Illinois Observatory used an early selenium cell photometer to produce the first-ever photoelectric study of a…
The nearest binary star Alpha Centauri, as photographed by the Hubble Space Telescope
Edge-on disc of gas and dust present around the binary star system HD 106906
Artist's conception of a cataclysmic variable system
Artist's impression of the binary star system AR Scorpii