Messier 82 (Cigar Galaxy)
Messier 82 is a well-known galaxy in the constellation "Big Dipper" at a distance of 11.4 million light-years. It was discovered on New Year's Eve
in 1774 by "Johann Elert Bode". The discovery was also made independently by P. Méchain in 1779, who reported it to Charles Messier.
With a brightness of +8.6mag and an apparent size of 11.2'x4.3', Messier 82 is quite bright and large, so that it can be seen even with modern
binoculars. Because of its special shape, it is also known as the "cigar galaxy". With its high northern declination of almost 70°, it can be observed
from Germany all year round - it is therefore circumpolar. However, it is best seen in the spring months when the galaxy is at the zenith.
In the sky, Messier 82 is close to the spiral galaxy Messier 81, which is also very bright, and is gravitationally bound to it. As a result, there have
even been several close encounters in the past, but currently the two galaxies are separated by around 200-600,000 light-years. They also form the
center of the so-called M81 group.
Due to the very chaotic appearance of Messier 82, it was originally classified as an irregular galaxy, but more recent observations in the infrared
show two symmetrical spiral arms, which are difficult to recognize because of the galaxy's orientation (80° inclination) and the many dark dust
filaments. As a result, Messier 82 is now classified as a barred spiral of the Hubble Type Sbc. It has a diameter of 41,000 light-years and shines
5 times brighter than our own Milky Way despite its small size and lower number of stars.
Messier 82 is also a "starburst galaxy", i.e. a galaxy in which around 10 times more stars are formed compared to "normal" galaxies. It does not
only shine very brightly in the infrared spectral range, but is also one of the brightest objects in the radio range - hence the further designation
"UMa A". The high star formation rate is responsible for the fact that many hot and luminous stars have formed in the recent past, which "push"
the gas out of the galaxy with their turbulent stellar winds. These filaments are particularly impressive to observe in the halpha range. In the central
region there are also around 200 very young star clusters (SSC) with an age of just 4-6 million years and a mass of around 200,000 solar masses each.
Like all large galaxies, Messier 82 also has a supermassive black hole (SMBH) at its center, with an estimated mass of around 30 million solar masses.
The brightest supernova in M82 to date was observed in 2014. It reached a maximum brightness of 10.5mag and was therefore visible even in small
telescopes. It was a type Ia supernova.
----------------------------------------------------------------------------------------------------------------------------------------------
Messier 82 offers a wonderful sight in a 20" telescope under a dark sky that is hard to get enough of. :)
Even at a low magnification of 120x, the galaxy appears very bright because of its high surface brightness and the two largest dust filaments that cut
through the galaxy body from north to south can already be seen. Increasing the magnification to 270x, the galaxy breaks up into a multitude of bright
areas and patches of varying brightness. In addition, several dust filaments can now be seen. It is particularly interesting that there is a kind of light
bridge above the central dust band, which was clearly visible with indirect vision.
In moments of very calm air, you can also search for some of the superclusters (SSC) mentioned above, of which I was able to recognize a total of 10.
They appear as extremely faint stellar dots and were mainly visible in the southern part of Messier 82.
Observing the gas filaments that are pushed out of the galaxy is very difficult. The southern stellar wind (below Messier 82) is the more easily visible
of the two and could be seen with averted vision as an extremely faint glow. The northern stellar wind is significantly weaker and does not extend that
far into space.
