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Alioth - ε Ursae Majoris (epsilon Ursae Majoris)

Alioth, also designated as ε Ursae Majoris (epsilon Ursae Majoris), is a variable hypergiant star in the constellation of Ursa Major.

Alioth visual magnitude is 1.77, making it the 31th brightest star in the sky. Thanks to its high brightness, Alioth is clearly visible when observed from locations with dark skyes, and should be also quite easily visible from light polluted areas.

The table below summarizes the key facts about Alioth:

Color of Alioth ⬤

Magnitude of Alioth 1.77

Class Hypergiant

VISIBILITY RIGHT NOW Alioth - ε Ursae Majoris (epsilon Ursae Majoris) is above the horizon from Greenwich, United Kingdom edit_location_alt. Altitude: 18°.

Celestial coordinates and finder chart of Alioth

Alioth is situated north of the celestial equator, as such, it is more easily visible from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of Alioth are provided in the following table:

Right Ascension J2000 12h 54m 01s

Declination J2000 +55° 57’ 34”

Galactic Longitude 122.18°

Galactic Latitude 61.16°

Constellation Ursa Major

The simplified sky map below shows the position of Alioth in the sky:

Finder chart Alioth - ε Ursae Majoris (epsilon Ursae Majoris) star

Simplified finder chart for Alioth - ε Ursae Majoris (epsilon Ursae Majoris).

Visibility of Alioth from your location

Location: Greenwich, United Kingdom edit_location_alt
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
Timezone: Europe/London

Alioth - ε Ursae Majoris (epsilon Ursae Majoris) is circumpolar and transits at 20:05 UTC (altitude: 85.5°)

Digitized Sky Survey image of Alioth

The image below is a photograph of Alioth from the Digitized Sky Survey 2 (DSS2 - see the credits section) taken in the red channel. The area of sky represented in the image is 0.5x0.5 degrees (30x30 arcmins). The proper motion of Alioth is 0.112 arcsec per year in Right Ascension and -0.006 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of Alioth - ε Ursae Majoris (epsilon Ursae Majoris) star

DSS2 image of Alioth. The red arrow shows the motion of Alioth during the next 1000 years (1.87 arcmin in Right Ascension and -0.10 arcmin in declination);

Distance of Alioth from the Sun and relative movement

Alioth is distant 80.89 light years from the Sun and it is moving towards the Sun at the speed of 9 kilometers per second.

Distance (parsec) 24.81 pc

Distance (light year) 80.89 ly

Heliocentric radial velocity -9 km/s

Proper Motion RA 0.112 arcsec/year

Proper Motion Dec -0.006 arcsec/year

Spectral properties of Alioth

Alioth belongs to spectral class A0 Alioth is also a Cr chemically peculiar star.

Absolute magnitude -0.20

Spectral Type A0

Color Index (B-V) -0.02

Temperature of Alioth 10382K

The red dot in the diagram below shows where Alioth is situated in the Hertzsprung–Russell diagram.

H-R diagram showing the position of Alioth. Attribution: Richard Powell / CC BY-SA

Alternative designations of Alioth

Proper Name Alioth

Bayer designation ε Ursae Majoris
(epsilon Ursae Majoris)

Flamsteed designation 77 Ursae Majoris

Henry Draper Catalogue HD112185

SAO Catalogue SAO28553

Hipparcos Catalogue HIP62956

Durchmusterung Catalogue BD+56 1627

FK5 Catalogue 483

General Catalogue of Variable Stars Eps UMa

In Evidence

Other stars in Ursa Major