Elliptical galaxies are a type of galaxy that are round or oval in shape and are mostly made up of older stars; it is believed that many galaxy collisions end up creating elliptical galaxies, and that eventually they will become more common as the universe ages. They vary in size; dwarf elliptical galaxies can be made up of just a few million stars, while the largest of them can have trillions.
Elliptical galaxies make up approximately 10-15% of large galaxies in the Virgo Supercluster.
Elliptical galaxies are designated with the type En, with n equal to:
where is the galaxy's major axis and is its minor axis. In general, elliptical galaxies range from E0 to E7. Beyond E7, an instability called the firehose instability occurs which causes the galaxy to buckle up and become rounder. The most common type of elliptical galaxy is E3.
Well-known elliptical galaxies in our universe include IC 1101 (the largest galaxy we know to this day), M87, and Maffei 1.
| E · S0 · SA · SB · SM · Irr |
dSph · dE · dIrr