A barred irregular galaxy is an irregular version of a barred spiral galaxy. They have a bar-shaped structure in the middle of an otherwise irregular shape. Examples include the Large Magellanic Cloud (LMC) [1] and NGC 6822, [2] although LMC is more often classified as a magellanic spiral galaxy. Some barred irregular galaxies (like the Large Magellanic Cloud) may be dwarf spiral galaxies, which have been distorted into an irregular shape by tidal interactions with a more massive neighbor.
Barred irregular galaxies are part of a broader classification of galaxies that do not fit neatly into the Hubble sequence of elliptical and spiral galaxies. The presence of a central bar is a significant feature, as bars are found in approximately two-thirds of all spiral galaxies. [3] These bars are thought to form from density waves that reshape the orbits of stars near the galactic center.
The irregular shape of these galaxies is often a result of gravitational interactions with other, larger galaxies. [4] When a smaller galaxy, such as a dwarf spiral, passes close to a more massive one, the tidal forces can strip away stars and gas, creating tidal tails and disrupting the galaxy's morphology. This process can transform a regular spiral galaxy into an irregular one, and if the original galaxy was a barred spiral, it would become a barred irregular galaxy.