Ursa Major

Ursa Major (Latin: "Larger She-Bear"; also known as the Great Bear) is a constellation visible 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 asterism known as the Big Dipper or the Plough, which is a useful pointer towards the north, and it has mythological significance in numerous world cultures.

Big Dipper

The seven brightest stars of Ursa Major form the asterism known as the Big Dipper in the USA and Canada, the Plough in the United Kingdom, the Großer Wagen in Germany & Austria and the Saptarshi in India. Six of these seven stars are of 2nd magnitude; just the central star is of 3rd magnitude. Another asterism known as the "Three Leaps of Gazelle"[2] is recognized in Arab culture, a series of three pairs of stars: ν and ξ Ursae Majoris, Alula Borealis and Australis, the "first leap";λ and μ Ursae Majoris, Tania Borealis and Australis, the "second leap";ι and κ Ursae Majoris, Talitha Borealis and Australis, the "third leap".

These stars are found along the southwest border of the constellation.

Deep Sky Objects

Several bright galaxies are found in Ursa Major, including the pair Messier 81 (one of the brightest galaxies in the sky) and Messier 82 above the bear's head, and Pinwheel Galaxy.

• Messier 101, a spiral northeast of η Ursae Majoris. The spiral galaxies Messier 108 and Messier 109 are also found in this constellation. The bright planetary nebula Owl Nebula (M97) can be found along the bottom of the bowl of the Big Dipper.

• Messier 81 is a nearly face-on spiral galaxy 11.8 million light-years from Earth. Like most spiral galaxies, it has a core made up of old stars, with arms filled with young stars and nebulae. Along with M82, it is a part of the galaxy cluster closest to the Local Group.

• Messier 82 is a galaxy that is interacting gravitationally with M81. It is the brightest infrared galaxy in the sky.[12] SN 2014J, an apparent Type Ia supernova, was observed in M82 on 21 January 2014.[13]

• Messier 97, also called the Owl Nebula, is a planetary nebula 1,630 light-years from Earth; it has a magnitude of approximately 10. It was discovered in 1781 by Pierre Méchain.[14]

• Messier 101, also called the Pinwheel Galaxy, is a face-on spiral galaxy located 25 million light-years from Earth. It was discovered by Pierre Méchain in 1781. Its spiral arms have regions with extensive star formation and have strong ultraviolet emissions. It has an integrated magnitude of 7.5, making it visible in both binoculars and telescopes, but not to the naked eye.

• NGC 2787 is a lenticular galaxy at a distance of 24 million light-years. Unlike most lenticular galaxies, NGC 2787 has a bar at its center. It also has a halo of globular clusters, indicating its age and relative stability.[12]

• NGC 3079 is a starburst spiral galaxy located 52 million light-years from Earth. It has a horseshoe-shaped structure at its center that indicates the presence of a supermassive black hole. The structure itself is formed by superwinds from the black hole.[12]

• NGC 3310 is another starburst spiral galaxy located 50 million light-years from Earth. Its bright white color is caused by its higher than usual rate of star formation, which began 100 million years ago after a merger. Studies of this and other starburst galaxies have shown that their starburst phase can last for hundreds of millions of years, far longer than was previously assumed.[12]

• NGC 4013 is an edge-on spiral galaxy located 55 million light-years from Earth. It has a prominent dust lane and has several visible star forming regions.[12]

• I Zwicky 18 is a young dwarf galaxy at a distance of 45 million light-years. The youngest known galaxy in the visible universe, I Zwicky 18 is about 4 million years old, about one-thousandth the age of the Solar System. It is filled with star forming regions which are creating many hot, young, blue stars at a very high rate.[12]

• The Hubble Deep Field is located to the northeast of δ Ursae Majoris.

HGS Session References

HGS Sessions - Clearing Hyperspace Phantom Matrix - 3/12/2015

References

Found in HGS Manual on Page 108

Found in HGS Manual on Page 115