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Southern Pinwheel Galaxy

M83, NGC 5236

Proper NameSouthern Pinwheel Galaxy
Messier NumberM83
NGC/IC NumberNGC 5236
Right Ascension13h 37m 1s
Declination-29° 51' 57"
Distancec.16,000,000 light years
c.4,900,000 parsecs
MagnitudeApparent: +7.09
Absolute: -21.36
DiameterApparent: 13.6'
Actual: 63,300 light years
Hubble TypeSABc weakly barred spiral
Optimum VisibilityApril / May

A galaxy that lies some sixteen million light years from the Solar System. Its name comes from a general resemblance to the northern Pinwheel Galaxy in Ursa Major: both Pinwheels are spiral in form, and angled so that they appear face-on to an observer on Earth, but they are otherwise unrelated.

While the northern Pinwheel is a typical spiral galaxy, the Southern Pinwheel is a barred spiral. A weak but distinct bar of material runs through the galaxy's core, and from the ends of this bar extend two spiral arms that encircle the galaxy, in which several supernovae have been observed.

Imagery provided by Aladin sky atlas

The Southern Pinwheel is part of a group of galaxies that spreads southward from Virgo through Hydra and into Centaurus. This widely spread collection of galaxies is named the Centaurus A/M83 Group, taking that name in part from this galaxy (whose number in the Messier Catalogue is M83). It forms the core of a subgroup of galaxies within the larger group, a subgroup which may indeed be a separate cluster of galaxies in its own right.

In the skies of Earth, the Southern Pinwheel or M83 lies in the constellation of Hydra the Sea Monster, at the point where the monster's tail interposes itself between Virgo and Centaurus.


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