Science Fair Project Encyclopedia
Categories: Bayer objects | Double stars | Orange giants | Triple star systems | Ursa Major constellation | Yellow-white dwarfs
Dubhe
Dubhe (α Ursae Majoris) is the second-brightest star in the constellation of Ursa Major. It forms part of the Plough (also known as the Big Dipper), and is the northern-most of the pointers, the two stars of Ursa Major which point towards the Pole Star.
The name comes from the Arabic for "bear", dubb, from the phrase ظهر الدب الاكبر aż-żahr ad-dubb al-akbar "the back of the Great Bear".
Five stars in the Plough are young hot stars which share a common origin and are moving together through space, but Dubhe is not one of them. Instead, it is an evolved helium-burning star, about 124 light years away. It is a K-type star with a surface temperature of about 4500K, and is approximately 300 times more luminous than the Sun. It is a multiple star, orbited by a main sequence companion at a distance of about 23 astronomical units (AU), as well as another double star at a distance of about 8000AU.
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