Celestial hemisphere:  Northern  ·  Constellation: Ursa Major (UMa)  ·  Contains:  Bode's Galaxy  ·  Cigar Galaxy  ·  M 81  ·  M 82  ·  NGC 3031  ·  NGC 3034  ·  PGC 2726822  ·  PGC 2730379  ·  PGC 2730409  ·  PGC 2730709  ·  PGC 2730975  ·  PGC 2731294  ·  PGC 2732102  ·  PGC 2732338  ·  PGC 28529  ·  PGC 28757  ·  PGC 28848  ·  PGC 3086325  ·  PGC 3097961
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M81 & M82 - 2021, Gary Imm
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M81 & M82 - 2021

Getting plate-solving status, please wait...
M81 & M82 - 2021, Gary Imm
Powered byPixInsight

M81 & M82 - 2021

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Description

This image captures two magnificent galaxies in the same field of view, located about 12 million light years away in the constellation of Ursa Major. M81, at upper right, is a grand design spiral galaxy, while M82 is an irregular galaxy. Scientists believe that these two galaxies are interacting gravitationally.

At a diameter of 92,000 light years, M81 is slightly smaller in size than our Milky Way. Its disk is inclined to us at 59 degrees. Surprisingly to me, this angle is slightly more edge-on (90 degrees) than face-on (0 degrees). I like the numerous pinkish Ha regions and bluish star clusters. These indicate ongoing star formation which likely was initiated by the interaction with M82. This galaxy was first discovered by Johann Bode in 1774 and is sometimes referred to as "Bode's Galaxy", one of the few galaxies named after an individual. I like the detailed dark dust lanes above the core.

Seen slightly below and to the right of M81 is the dwarf irregular blue galaxy Holmberg IX, designated PGC 28757 in the mouseover. This galaxy is a satellite galaxy of M81. A 2006 paper by Sabbi et al described this galaxy as the nearest young galaxy, with an age of 200 million years.

M82 has a fascinating, irregular, distorted disk due to the interaction of its larger neighbor. It is half the size of M81. Our view of this galaxy is almost edge-on, at an inclination angle of 77 degrees. It is also known as Arp 337. The structure of this galaxy is so unusual that Dr. Halton Arp couldn't classify it, and it fell into the last category of the catalog called "Miscellaneous". It is called a starburst galaxy because it is undergoing a burst of new star formation. Through powerful winds from massive emerging stars, this burst of star formation in M82 is driving a huge outflow of reddish hydrogen gas from its galaxy core unlike that of any other galaxy. I like the dark lanes of dust running in strange patterns around the core of this unique galaxy.

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