Upsilon Ursae Majoris
Epoch J2000.0 Equinox J2000.0
|Right ascension||09h 50m 59.4s|
|Declination||+59° 02′ 19″|
|Apparent magnitude (V)||+3.78|
|Distance||115 ± 3 ly
(35 ± 1 pc)
|Spectral type||F2 IV|
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 variable star and its brightness varies from magnitude +3.68 to +3.86 with a period of 3.18 hours.[dubious ] 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.
The companion, Upsilon Ursae Majoris B, is a magnitude +11.5 star, 11.3 arcseconds away from the primary.
- With τ, h, φ, θ, e, and f, it composed the Arabic asterism Sarīr Banāt al-Na'sh, the Throne of the daughters of Na'sh, and al-Haud, the Pond,
- In Chinese, 文昌 (Wén Chāng), meaning Administrative Center, refers to an asterism consisting of υ Ursae Majoris, φ Ursae Majoris, θ Ursae Majoris, 15 Ursae Majoris and 18 Ursae Majoris. Consequently, υ Ursae Majoris itself is known as 文昌二 (Wén Chāng èr, English: the Second Star of Administrative Center.).
- 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
- Allen, Richard Hinckley (1899), Star-Names and Their Meanings, New York: G. E. Stechert, p. 442
- (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 16 日
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