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Alioth

Epsilon Ursae Majoris, 77 Ursae Majoris

Proper NamesAlioth
Bayer DesignationEpsilon Ursae Majoris
Flamsteed Number77 Ursae Majoris
HR (BSC)4905
HD112185
ConstellationUrsa Major
Right Ascension12h 54m 56s
Declination+55° 50' 54"
Distance83 light years
25 parsecs
MagnitudeApparent: +1.8
Absolute: -0.3
Spectral ClassA0VpSiSr White Main Sequence Star
Optimum VisibilityMarch / April (Usually visible from northern latitudes)
Optimum VisibilityAlioth is one of the seven stars that make up the Plough or Big Dipper formation. It lies in the middle of the handle, and is marginally brighter than Dubhe or Alpha Ursae Majoris, in the Plough's share, which makes it - by a small margin - the brightest of all the stars in Ursa Major.

Despite its 'epsilon' designation, Alioth is the brightest star in Ursa Major, with a magnitude of +1.8. This white star exhibits variability of the type demonstrated by Cor Caroli (or specifically by its Alpha2 Canum Venaticorum component): that is, Alioth's apparent brightness changes due to markings on its surface as the star rotates.

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