Upsilon Ursae Majoris

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Upsilon Ursae Majoris
Diagram showing star positions and boundaries of the Ursa Major constellation and its surroundings
Diagram showing star positions and boundaries of the Ursa Major constellation and its surroundings

Location of υ Ursae Majoris (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Major
Right ascension 09h 50m 59.4s
Declination +59° 02′ 19″
Apparent magnitude (V) +3.78
Spectral type F2 IV[1]
Distance 115 ± 3 ly
(35 ± 1 pc)
Other designations
υ Ursae Majoris, υ UMa, Upsilon UMa, 29 Ursae Majoris, BD+59 1268, CCDM J09510+5902A, FK5368, GC 13540, HD 84999, HIP 48319, HR 3888, IDS 09439+5931, PPM 32349, SAO 27401, WDS J09510+5902A.
Database references

Upsilon Ursae Majoris (Upsilon UMa, υ Ursae Majoris, υ UMa) is a binary star in the constellation Ursa Major. It is approximately 115 light years from Earth.

The primary component, Upsilon Ursae Majoris A, is a yellow-white F-type subgiant with a mean apparent magnitude of +3.78. It is classified as a Delta Scuti type[1] variable star and its brightness varies from magnitude +3.68 to +3.86 with a period of 3.18 hours.[2] It has a projected rotational velocity of 110 km s−1, an effective temperature of 7,080 K, and a luminosity 29–30 times that of the Sun.[1]

The companion, Upsilon Ursae Majoris B, is a magnitude +11.5 star, 11.3 arcseconds away from the primary.[3]



  1. ^ a b c Balona, L. A.; Dziembowski, W. A. (October 1999), "Excitation and visibility of high-degree modes in stars", Monthly Notices of the Royal Astronomical Society, 309 (1): 221–232, Bibcode:1999MNRAS.309..221B, doi:10.1046/j.1365-8711.1999.02821.x 
  2. ^ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S. 
  3. ^ Dommanget, J.; Nys, O. (1994). "Catalogue des composantes d'etoiles doubles et multiples (CCDM) premiere edition - Catalogue of the components of double and multiple stars (CCDM) first edition". Com. de l'Observ. Royal de Belgique. 115: 1. Bibcode:1994CoORB.115....1D. 
  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