Upsilon Ursae Majoris
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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 |
| Distance | 115 ± 3 ly (35 ± 1 pc) |
| Spectral type | F2 IV[1] |
| Other designations | |
Upsilon Ursae Majoris (υ UMa, υ Ursae Majoris) 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.
[edit] 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
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