Upsilon Ursae Majoris
 Location of υ Ursae Majoris (circled) |
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| Observation data Epoch J2000.0 Equinox J2000.0 |
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|---|---|
| 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.[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.[1]
The companion, Upsilon Ursae Majoris B, is a magnitude +11.5 star, 11.3 arcseconds away from the primary.
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,[2]
- 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.).[3]
References
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