M 82

Right Ascension	09 : 55.8 (h:m)
Declination	+69 : 41 (deg:m)
Distance	12000 (kly)
Visual Brightness	8.4 (mag)
Apparent Dimension	9x4 (arc min)

Forming a most conspicuous physical pair with its neighbor, M81 (THE showpiece galaxies for many Northern hemispherers), this galaxy is the prototype of an irregular of the second type, i.e. a "disk" irregular. Its core seems to have suffered dramatically from a semi-recent close encounter with M81, being in a heavy starburst and displaying conspicuous dark lanes. This turbulent explosive gas flow is also a strong source of radio noise. In the infrared light, M82 is the brightest galaxy in the sky; it exhibits a so-called infrared excess (it is much brighter at infrared wavelengths than in the visible part of the spectrum). This behaviour can also be observed for the companion of M51, NGC 5195, and the peculiar galaxy NGC 5128 (Centaurus A). The visual appearance is that of a silvery sliver, as John Mallas decribed it.

As a member of the M81 group, M82 is 12 million light years distant.

More images of M81 and M82

M82 belongs to those few Messier objects which have been assigned a Herschel number, H IV.79, while William Herschel usually carefully avoided to give his numbers to Messier objects.

Lebofsky, Rieke, and Kailey reported the discovery of a supernova, 1986D, which should have occurred in M82, and is e.g. listed in Kenneth Glyn Jones' book. However, this "SN" turned out to be a false alarm. Instead, a slightly variable 2-micrometer source had fooled the discoverers.

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