Bode's Galaxy (M81) and the Cigar Galaxy (M82)

by Craig and Tammy Temple

M81 & M82, also known as Bode's & Cigar, are a pair of galaxies that lie around 12 million light-years away in the constellation Ursa Major (the Big Dipper). The spiral galaxy on the right is Bode's Galaxy, and is also known as Messier 81 or NGC 3031. The Cigar Galaxy (Messier 82 or NGC 3034) is the starburst galaxy on the left. Bode's proximity to Earth, its large size, relatively high brightness (apparent magnitude 6.94), and its active galactic nucleus, which is home to a supermassive black hole, make it a popular target for both professional and amateur astronomers alike. Just below Bode's Galaxy, at a distance of 12 million light-years away, is a dwarf irregular galaxy with an apparent magnitude of 16.5 known as Holmberg IX and is a satellite galaxy of Bode's. Holmberg IX was named after Erik Holmberg who was the first to describe it. This galaxy is thought to have formed within the last 200 million years, making it the youngest nearby galaxy. Although the Cigar galaxy, with an apparent magnitude of 8.41, is dimmer than Bode's, it is five times as bright as our entire Milky Way and one hundred times as bright as our galaxy's center. M82's classification as a starburst galaxy means it is in the process of an exceptionally high rate of star formation, so much so, that in 2005, the Hubble Space Telescope revealed 197 young massive clusters in its starburst core. M82 was discovered along with M81 on December 31, 1774 by Johann Elert Bode. Pierre Mechain rediscovered the pair as nebulous patches in August 1779 and reported them to Charles Messier who later added them to his catalog on February 9, 1781. Halton Arp has included M82 in his Catalogue of Peculiar Galaxies as No. 337.