Ursa Major( Latin: "Larger Bear"; also known as theGreat BearandCharles' Wain [ 1 ]) is a constellationvisible throughout the year in most of the northern hemisphere. It can be seen best in the month of April. It is dominated by the widely recognized asterismknown as the Big Dipperor the Plough, which is a useful pointer towards the north, and it has mythological significance in numerous world cultures.
Asterisms
Main article: Big Dipper
The seven brightest starsof Ursa Major form the asterismknown as theBig Dipperin the USA and Canada, thePloughin the United Kingdom, theGroßer Wagenin Germany & Austria and theSaptarshiin India.
Six of these seven stars are of 2nd magnitude, just the central star is of 3rdmagnitude.
Another asterism known as the "Three Leaps of Gazelle" [ 2 ]is recognized in Arab culture, a series of three pairs of stars:
*. νand ξUrsae Majoris, Alula Borealisand Australis, the "first leap";
*. λand μUrsae Majoris, Tania Borealisand Australis, the "second leap";
*. ιand κUrsae Majoris, Talitha Borealisand Australis, the "third leap".
These stars are found along the southwest border of the constellation.
Notable features
The constellation Ursa Major as it can be seen by the unaided eye.
Stars
The " Big Dipper" (or "Plough") asterismwithin Ursa Major is made up of seven bright stars that together comprise one of the best-known patterns in the sky, while also forming the hindquarters and tail of the Great Bear. Starting with the "ladle" portion of the dipper and extending clockwise through the handle, these stars are the following:
*. α Ursae Majoris, known by the Arabic name Dubhe("the bear"), which at a magnitude of 1.79 is the 35th brightest star in the sky and the second brightest of Ursa Major.
*. β Ursae Majoris, called Merak ("the loins of the bear"), with a magnitude of 2.37.
*. γ Ursae Majoris, or Phecda("thigh"), with a magnitude of 2.44.
*. δ Ursae Majoris, or Megrez, meaning "root of the tail," an appropriate name given its location as the intersection of the body and tail of the bear (or the ladle and handle of the dipper).
*. ε Ursae Majoris, known as Alioth, a name which refers not to a bear but to a "black horse," the name corrupted from the original and mis-assigned to the similarly named Alcor, the naked-eye binary companion of Mizar. [ 3 ]Alioth is the brightest star of Ursa Major and the 33rd brightest in the sky, with a magnitude of 1.76. It is also the brightest of the "peculiar A (Ap) stars," magnetic stars whose chemical elements are either depleted or enhanced, and appear to change as the star rotates. [ 4 ]
*. ζ Ursae Majoris, Mizar, the second star in from the end of the handle of the Big Dipper, and the constellation's fourth brightest star. Mizar, which means "girdle," forms a famous double star, with its optical companion Alcor(80 Ursae Majoris), the two of which were termed the "horse and rider" by the Arabs.
*. η Ursae Majoris, known as either Alkaidor Benetnash, both meaning the "end of the tail." With a magnitude of 1.85, Alkaid is the third-brightest star of Ursa Major.
