(galaxy that's not a disk or ellipsoid)
Irregular galaxy is a catch-all term for galaxies
that do not fit the more defined shapes such as
spiral galaxy or elliptical galaxy.
- Irr-I - has hints of structure. (The Sm classification that uses the Magellanic Clouds as its prototypes is now sometimes used for some of these.)
- Irr-II - no such hints. The classification amorphous galaxy is a refinement of this classification.
- dIrr - dwarf irregular.
Irregular galaxies can have bars (i.e., a barred irregular galaxy).
Some are considered the results of galaxy mergers
and tidal forces in other galaxy interactions.
Referenced by pages:
Canis Major Dwarf Galaxy
dwarf galaxy classification
Large Magellanic Cloud (LMC)
Magellanic clouds (MC)
Sagittarius Dwarf Irregular Galaxy (SagDIG)
Small Magellanic Cloud (SMC)