Algol

E554030

Algol is a famous eclipsing binary star system known for its regular brightness variations and is one of the best-studied variable stars in the night sky.

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Observed surface forms (3)

Surface form Occurrences
Algol A 0
Algol B 0
Algol C 0

Statements (49)

Predicate Object
instanceOf Beta Lyrae-type eclipsing binary
eclipsing binary star system
main-sequence star
spectroscopic binary
subgiant star
variable star
alsoKnownAs Beta Persei NERFINISHED
Demon Star NERFINISHED
β Persei NERFINISHED
hasApparentMagnitudeAtMaximum about 2.1
hasApparentMagnitudeAtMinimum about 3.4
hasApparentMagnitudeRange 2.1 to 3.4
hasBayerDesignation β Persei NERFINISHED
hasComponent Algol A NERFINISHED
Algol B NERFINISHED
Algol C NERFINISHED
hasCulturalAssociation traditionally associated with a demon or ghoul in Arabic astronomy
hasDeclination +40° 57′ 20″
hasDiscoveryAsVariableStarBy Gemini astronomer John Goodricke NERFINISHED
hasDistanceFromEarth about 28 parsecs
about 90 light-years
hasEccentricity approximately 0 (nearly circular orbit)
hasFlamsteedDesignation 26 Persei NERFINISHED
hasInclination about 81 degrees
hasLightCurve characteristic flat maxima with sharp eclipses
hasLuminosityOfPrimary about 100 times solar luminosity
hasLuminosityOfSecondary about 4 times solar luminosity
hasMassOfPrimary about 3.2 solar masses
hasMassOfSecondary about 0.8 solar masses
hasOrbitalPeriod about 2.867 days
hasParallax about 35.0 milliarcseconds
hasPrimaryEclipseDuration about 10 hours
hasRadiusOfPrimary about 2.9 solar radii
hasRadiusOfSecondary about 3.5 solar radii
hasRightAscension 03h 08m 10.1s
hasSpectralType A7m
A7m for Algol C
B8V
B8V for Algol A
K2IV
K2IV for Algol B
hasVariabilityPeriod about 2.867 days
hasVariableStarDesignation Beta Persei NERFINISHED
hasVariableType EA (Algol-type eclipsing binary)
isOneOfBestStudiedVariableStars true
isPrototypeOf Algol-type eclipsing binaries
locatedInConstellation Perseus NERFINISHED
nameOrigin derived from Arabic "raʾs al-ghūl" meaning "head of the demon"
wasIdentifiedAsEclipsingBinaryInYear 1783

Referenced by (1)

Full triples — surface form annotated when it differs from this entity's canonical label.