Upsilon Ursae Majoris
  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 |
| Characteristics | |
| Spectral type | F2 IV[1] |
| Astrometry | |
| Distance | 115 ± 3 ly (35 ± 1 pc) |
| Other designations | |
| Database references | |
| SIMBAD | data |
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]
Naming
- 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,[4]
- In Chinese, 文昌 (Wén Chāng), meaning Administrative Center, refers to an asterism consisting of υ Ursae Majoris, 44 Lyncis, φ Ursae Majoris, θ Ursae Majoris, 15 Ursae Majoris and 18 Ursae Majoris. Consequently, υ Ursae Majoris itself is known as 文昌一 (Wén Chāng yī, English: the first Star of Administrative Center.).[5]
References
- ^ 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
- ^ 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.
- ^ 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.
- ^ Allen, Richard Hinckley (1899), Star-Names and Their Meanings, New York: G. E. Stechert, p. 442
- ^ Template:Zh icon 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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