Phi Ursae Majoris

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Phi Ursae Majoris
Phi Ursae Majoris is located in 100x100
Phi Ursae Majoris

Location of φ Ursae Majoris (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Major
Right ascension 09h 52m 06.36s
Declination +54° 03' 51.4"
Apparent magnitude (V) +4.55
Spectral type A3IV
Distance 436 ly
(134 pc)
Other designations
φ Ursae Majoris, φ UMa, Phi UMa, 30 Ursae Majoris, BD+54 1331, CCDM J09521+5404AB, GC 13559, HD 85235, HIP 48402, HR 3894, IDS 09453+5432, PPM 32355, SAO 27408, WDS J09521+5404AB
Database references

Phi Ursae Majoris (Phi UMa, φ Ursae Majoris, φ UMa) is binary star in constellation of Ursa Major, which is separated in 0.245 arcseconds.[1] Both of components are white A-type subgiant.[2] It is approximately 436 light years from Earth.

Phi Ursae Majoris is moving through the Galaxy at a speed of 21.6 km/s relative to the Sun. Its projected Galactic orbit carries it between 24,000 and 46,000 light years from the center of the Galaxy.[3]

Phi Ursae Majoris will come closest to the Sun 4.7 million years from now when it will brighten to magnitude 3.88 from a distance of 370 light years.[3]



  1. ^ Barnaby, David; Spillar, Earl; Christou, Julian.C; Drummond, Jack.D (January 2000), "Measurements of Binary Stars with the Starfire Optical Range Adaptive Optics Systems", The Astronomical Journal, 119 (1): 378–389, Bibcode:2000AJ....119..378B, doi:10.1086/301155 
  2. ^ PHI UMA (Phi Ursae Majoris)
  3. ^ a b Phi Ursae Majoris (HIP 48402)
  4. ^ Allen, Richard Hinckley (1899), Star-Names and Their Meanings, New York: G. E. Stechert, p. 442 
  5. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 16 日