vendredi 19 septembre 2008

Ursa Major 11

Theta Ursae Majoris (θ UMa / θ Ursae Majoris) is a binary star in the constellation Ursa Major. It is approximately 44.0 light years from Earth. It also has the traditional names Al Haud and Sarir.
The primary component, Theta Ursae Majoris A, is a yellow-white F-type subgiant with an apparent magnitude of +3.17. The 14th magnitude companion star is 4.1 arcseconds away from the primary.
Delta Ursae Majoris (δ UMa / δ Ursae Majoris) is a star in the constellation Ursa Major. It also has the traditional name Megrez (Arabic: مغرز).
Megrez has an apparent magnitude of +3.32 making it the dimmest of the seven stars in the Big Dipper. Located 81 light years away, it has spectral type A3. It has two faint companions, the 11th magnitude Delta Ursae Majoris B, 190 arcseconds away and the 10th magnitude Delta Ursae Majoris C, 186 arcseconds away.
It is part of the Ursa Major moving group.

Omicron Ursae Majoris (ο UMa / ο Ursae Majoris) is a star system in the constellation Ursa Major. It is approximately 184 light years from Earth. It also has the traditional name Muscida, which it shares with the optical double star Pi Ursae Majoris.
The primary component, Omicron Ursae Majoris A, is a yellow G-type giant with an apparent magnitude of +3.35. It has a 15th magnitude companion, Omicron Ursae Majoris B, which is 7 arcseconds from the primary. It is sometimes listed with two more companions, Omicron Ursae Majoris C and D but, based on proper motion data, these appear to be optical companions.
The star is also a variable star of unknown type with a period of 358 days and an amplitude of 0.5 magnitude.
Lambda Ursae Majoris (λ UMa / λ Ursae Majoris) is a star in the constellation Ursa Major. It also has the traditional names Tania Borealis, and Alkafzah Borealis.
Nu Ursae Majoris (ν UMa / ν Ursae Majoris) is a binary star in the constellation Ursa Major. It is approximately 421 light years from Earth and has the traditional name Alula Borealis (The word Alula comes from an Arabic phrase meaning ‘first leap’; the distinctions ‘northern’ (Borealis) and ‘southern’ (Australis) are added in Latin).
The primary component, Nu Ursae Majoris A, is an orange K-type giant with an apparent magnitude of +3.49. It has a 10th magnitude companion 7.1 arcseconds away.


Alula Australis Al-Qafzah al-Ula "the first leap" القفزةالأولى
Alula Borealis Al-Qafzah al-Ula "the first leap" القفزةالأولى

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