Polaris, also known as the North Star or Pole Star. By visually tracing a line from Merak through Dubhe (1 unit) and continuing for 5 units, one's eye will land on Polaris, accurately indicating true north. Another asterism known as the "Three Leaps of the Gazelle" is recognized in Arab culture. It is a series of three pairs of stars found along the southern border of the constellation. From southeast to southwest, the "first leap", comprising ν and ξ Ursae Majoris (Alula Borealis and Australis, respectively); the "second leap", comprising λ and μ Ursae Majoris (Tania Borealis and Australis); and the "third leap", comprising ι and κ Ursae Majoris, (Talitha Borealis and Australis respectively). Other stars W Ursae Majoris is the prototype of a class of contact binary variable stars, and ranges between 7.75m and 8.48m. 47 Ursae Majoris is a Sun-like star with a three-planet system. 47 Ursae Majoris b, discovered in 1996, orbits every 1078 days and is 2.53 times the mass of Jupiter. 47 Ursae Majoris c, discovered in 2001, orbits every 2391 days and is 0.54 times the mass of Jupiter. 47 Ursae Majoris d, discovered in 2010, has an uncertain period, lying between 8907 and 19097 days; it is 1.64 times the mass of Jupiter. The star is of magnitude 5.0 and is approximately 46 light-years from Earth. The star TYC 3429-697-1 ( ), located to the east of θ Ursae Majoris and to the southwest of the "Big Dipper") has been recognized as the state star of Delaware, and is informally known as the Delaware Diamond. 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 (M101), 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. M81 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. M82 is a nearly edgewise galaxy that is interacting gravitationally with M81. It is