|Description of object:
Messier 83 is the central galaxy of the
so-called M83 group of galaxies. It is a group of galaxies adjacent to the
local group, which extends over the constellations of Water Serpent (Hydra),
Centaur (Centaurus) and the southern part of Virgo. The M83 group is a subgroup
of a larger group of galaxies, the central galaxy of the second subgroup is NGC
5128 - Centaurus A, a large "starburst galaxy" and one of the strongest radio
sources in the sky. The two groups are physically close to each other and do
not seem to move relative to each other, which is why it is often regarded as a
single, larger group of galaxies.
Messier 83 is located at a distance of about 15 million light years
from the solar system in the constellation Hydra (water snake). With a diameter
of about 50,000 light years, it is only half the size of the Milky Way, but
otherwise very similar to our galaxy. It has a clearly visible spiral structure
with pronounced H-II regions and many open star clusters and a central bar of
old stars and is classified as a so-called intermediate spiral - between a
normal spiral galaxy and a barred spiral. In M83, supernova explosions are
common, 6 in the last century alone.
Messier 83 was the first galaxy discovered outside the Local Group,
and the third of all galaxies, after the Andromeda galaxy (M31) and M32, both
of which are in the constellation of Andromeda. M83 was discovered in 1751 by
Nicolas Louis de Lacaille.