Delta Ursae Majoris


Distance (Light Years) 81.4 ± 1.2
Apparent Magnitude 3.32
Color (B-V)0.08

Names For This Star

Megrez derives from the Arabic term Al Maghrez meaning "The Root of the Tail (of the Bear)."

The The Bright Star Catalog lists Kaffa in Becvar as an alternative designation for Megrez. I have no information about the origin or meaning of this name for the star.

Description of the Star

Megrez is a hot, white A3V main sequence star about 25 times as luminous as the sun. The spectral type implies an effective temperature of 9100 K, a mass of 2.6 solar masses, and a diameter about twice that of the sun.

According to Burnham, Megrez is part of a star cluster including at least 16 other stars from the Ursa Major area of the sky, as well as Mizar, Merak, Alcor, Phecda, and Alioth in the Big Dipper. The Ursa Major cluster represents an ellipsoidal volume of space about 30 ly long by 18 ly in width.

Other Designations For This Star


69 Ursae Majoris

Hipparcos Identifier (HIP Number)


Harvard Revised (HR Number)


Henry Draper Catalog (HD Number)


Bonner Durchmusterung (BD Number)

BD+57 1363
Smithsonian Astrophysical
Observatory compendium (SAO Number)

Fundamental Katalog (FK5 Number)



Copyright © 1998 - 2010 by Arnold V. Lesikar,
Professor Emeritus
Dept. of Physics, Astronomy, and Engineering Science,
St. Cloud State University,St. Cloud, MN 56301-4498

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