M81 Group
| M81 Group | |
|---|---|
 |
|
| Observation data (Epoch J2000) | |
| Constellation(s) | Ursa Major/Camelopardalis |
| Brightest member | M81 (pictured) |
| Number of galaxies | 34 |
| Other designations | |
| NGC 3031 Group | |
The M81 Group is a galaxy group in the constellations Ursa Major and Camelopardalis that includes the galaxies Messier 81 and Messier 82, as well as several other galaxies with high apparent brightnesses. The approximate center of the group is located at a distance of 3.6 Mpc, making it one of the nearest groups to the Local Group. The group is estimated to have a total mass of (1.03 ± 0.17)×1012M☉. The M81 Group, the Local Group, and other nearby groups all lie within the Virgo Supercluster (i.e. the Local Supercluster).
The table below lists galaxies that have been identified as associated with the M81 Group by I. D. Karachentsev.
Note that the object names used in the above table differ from the names used by Karachentsev. NGC, IC, UGC, and PGC numbers have been used in many cases to allow for easier referencing.
Messier 81, Messier 82, and NGC 3077 are all strongly interacting with each other. The gravitational interactions have stripped some hydrogen gas away from all three galaxies, leading to the formation of filamentary gas structures within the group. Moreover, the interactions have also caused some interstellar gas to fall into the centers of Messier 82 and NGC 3077, which has led to strong starburst activity (or the formation of many stars) within the centers of these two galaxies.
Galaxy UGC 8201 is a dwarf irregular galaxy member of the M81 galaxy group.
Amateur picture Messier 81 + 82 and NGC 3077 all of the M81 group, 33 frames stacked of 1 minute each.
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