Dubhe - α Ursae Majoris (alpha Ursae Majoris)

Altitude: 79.7° Azimuth: 358.9° Direction: North

Dubhe, also designated as α Ursae Majoris (alpha Ursae Majoris), is a variable and double hypergiant star in the constellation of Ursa Major.

Dubhe visual magnitude is 1.79, making it the 33th brightest star in the sky. Thanks to its high brightness, Dubhe 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 Dubhe:

Color of Dubhe ⬤

Magnitude of Dubhe 1.79

Class Hypergiant

VISIBILITY RIGHT NOW

Dubhe - α Ursae Majoris (alpha Ursae Majoris) is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 79.7°
Azimuth: 358.9°
Direction: North

Celestial coordinates and finder chart of Dubhe

Dubhe is situated close to the northern celestial pole and, as such, it is visible for most part of the year from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of Dubhe are provided in the following table:

Right Ascension J2000 11h 03m 43s

Declination J2000 +61° 45’ 02”

Galactic Longitude 142.85°

Galactic Latitude 51.01°

Constellation Ursa Major

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

Finder chart Dubhe - α Ursae Majoris (alpha Ursae Majoris) star

Simplified finder chart for Dubhe - α Ursae Majoris (alpha Ursae Majoris).

Visibility of Dubhe from your location

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

Dubhe - α Ursae Majoris (alpha Ursae Majoris) is circumpolar and transits at 10:51 UTC (altitude: 79.7°)

Digitized Sky Survey image of Dubhe

The image below is a photograph of Dubhe 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 Dubhe is -0.119 arcsec per year in Right Ascension and -0.067 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of Dubhe - α Ursae Majoris (alpha Ursae Majoris) star

DSS2 image of Dubhe. The red arrow shows the motion of Dubhe during the next 1000 years (-1.98 arcmin in Right Ascension and -1.12 arcmin in declination);

Distance of Dubhe from the Sun and relative movement

Dubhe is distant 123.58 light years from the Sun and it is moving towards the Sun at the speed of 9 kilometers per second.

Distance (parsec) 37.91 pc

Distance (light year) 123.58 ly

Heliocentric radial velocity -9 km/s

Proper Motion RA -0.119 arcsec/year

Proper Motion Dec -0.067 arcsec/year

Spectral properties of Dubhe

Dubhe belongs to spectral class K0 and has a luminosity class of III corresponding to a hypergiant star.

Absolute magnitude -1.10

Spectral Type K0III

Color Index (B-V) 1.07

Temperature of Dubhe 4581K

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

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

Dubhe star system properties

Dubhe is a visual double star which can be observed only with the help of very large telescopes. The table below shows key information about the Dubhe double sysyem:

Main star magnitude 1.79

Secondary star magnitude 4.79

Magnitude difference 3

Separation 0.5 arcsec

Alternative designations of Dubhe

Proper Name Dubhe

Bayer designation α Ursae Majoris
(alpha Ursae Majoris)

Flamsteed designation 50 Ursae Majoris

Henry Draper Catalogue HD95689

SAO Catalogue SAO15384

Hipparcos Catalogue HIP54061

Durchmusterung Catalogue BD+62 1161

FK5 Catalogue 417

General Catalogue of Variable Stars 5070

Aitken Double Star Catalogue ADS8035

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In Evidence

Other stars in Ursa Major