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Alkaid - η Ursae Majoris (eta Ursae Majoris)

Alkaid, also designated as η Ursae Majoris (eta Ursae Majoris), is a variable main-sequence star in the constellation of Ursa Major.

Alkaid visual magnitude is 1.86, making it the 37th brightest star in the sky. Thanks to its high brightness, Alkaid 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 Alkaid:

Color of Alkaid ⬤

Magnitude of Alkaid 1.86

Class Main-sequence

VISIBILITY RIGHT NOW Alkaid - η Ursae Majoris (eta Ursae Majoris) is above the horizon from Greenwich, United Kingdom edit_location_alt. Altitude: 16°.

Celestial coordinates and finder chart of Alkaid

Alkaid 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 Alkaid are provided in the following table:

Right Ascension J2000 13h 47m 32s

Declination J2000 +49° 18’ 47”

Galactic Longitude 100.69°

Galactic Latitude 65.32°

Constellation Ursa Major

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

Finder chart Alkaid - η Ursae Majoris (eta Ursae Majoris) star

Simplified finder chart for Alkaid - η Ursae Majoris (eta Ursae Majoris).

Visibility of Alkaid from your location

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

Alkaid - η Ursae Majoris (eta Ursae Majoris) is circumpolar and transits at 21:03 UTC (altitude: 87.8°)

Digitized Sky Survey image of Alkaid

The image below is a photograph of Alkaid 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 Alkaid is -0.122 arcsec per year in Right Ascension and -0.011 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of Alkaid - η Ursae Majoris (eta Ursae Majoris) star

DSS2 image of Alkaid. The red arrow shows the motion of Alkaid during the next 1000 years (-2.03 arcmin in Right Ascension and -0.18 arcmin in declination);

Distance of Alkaid from the Sun and relative movement

Alkaid is distant 100.65 light years from the Sun and it is moving towards the Sun at the speed of 11 kilometers per second.

Distance (parsec) 30.87 pc

Distance (light year) 100.65 ly

Heliocentric radial velocity -11 km/s

Proper Motion RA -0.122 arcsec/year

Proper Motion Dec -0.011 arcsec/year

Spectral properties of Alkaid

Alkaid belongs to spectral class B3 and has a luminosity class of V corresponding to a main-sequence star.

Absolute magnitude -0.59

Spectral Type B3V

Color Index (B-V) -0.19

Temperature of Alkaid 13348K

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

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

Alternative designations of Alkaid

Proper Name Alkaid

Bayer designation η Ursae Majoris
(eta Ursae Majoris)

Flamsteed designation 85 Ursae Majoris

Henry Draper Catalogue HD120315

SAO Catalogue SAO44752

Hipparcos Catalogue HIP67301

Durchmusterung Catalogue BD+50 2027

FK5 Catalogue 509

General Catalogue of Variable Stars 6450

In Evidence

Other stars in Ursa Major