Omega Ursae Majoris

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Omega Ursae Majoris
Diagram showing star positions and boundaries of the Ursa Major constellation and its surroundings
Cercle rouge 100%.svg

Location of ω Ursae Majoris (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Major
Right ascension 10h 53m 58.7s
Declination +43° 11' 24"
Apparent magnitude (V) +4.66
Distance 267 ± 15 ly
(82 ± 5 pc)
Spectral type A1V s
Other designations
ω Ursae Majoris, ω UMa, Omega UMa, 45 Ursae Majoris, BD+43 2058, FK5 2870, GC 14974, HD 94334, HIP 53295, HR 4248, PPM 52125, SAO 43512.

Omega Ursae Majoris (Omega UMa, ω Ursae Majoris, ω UMa) is a binary star in the constellation Ursa Major. It is approximately 267 light years from Earth.

Omega Ursae Majoris is a spectroscopic binary which is classified as a white A-type main sequence dwarf with an apparent magnitude of +4.66. The binary system has an orbital period of 15.8 days.


In Chinese, 天牢 (Tiān Láo), meaning Celestial Prison, refers to an asterism consisting of ω Ursae Majoris, 57 Ursae Majoris, 47 Ursae Majoris, 58 Ursae Majoris, 49 Ursae Majoris and 56 Ursae Majoris. Consequently, ω Ursae Majoris itself is known as 天牢一 (Tiān Láo yī, English: the First Star of Celestial Prison.).[1]