Table of Contents
What is irregular galaxy?
Irregular galaxies are the most unusual of galaxies. They don’t seem to fit into either the spiral or elliptical galaxy categories. They don’t have nice spiral arms, but they do have dark patches of gas and dust. Galaxies that don’t have a spiral or elliptical shape are often called irregular galaxies.
What causes an irregular galaxy?
One way irregular galaxies are formed is when galaxies collide or come close to one another, and their gravitational forces interact. Another source of irregular galaxies may be very young galaxies that have not yet reached a symmetrical state.
What is an irregular galaxy NASA?
Irregular galaxies are among the smallest galaxies scientists have observed. However, they can also be very bright. Like spiral galaxies, irregular galaxies are often filled with gas, dust, and lots of bright young stars. About 20% of all galaxies are irregular galaxies.
Do irregular galaxies have a halo?
They have a bulge and halo, like spiral galaxies, but don’t have the flat disk of stars. The stars in ellipticals tend to be older. Irregular galaxies have no identifiable shape or structure to them. They are often chaotic in appearance, without a bulge or any trace of spiral arms.
Do irregular galaxies have black holes?
Many irregulars do not have supermassive black holes in their centers. These are typically the smallest irregular galaxies, like I Zwicky 18. Instead of black holes, many have “nuclear star clusters”, which are dense knots of many thousands of stars.
Is the Milky Way an irregular galaxy?
Our own Milky Way is a spiral galaxy, for example, and the largest galaxies in the Universe are elliptical galaxies. These are the irregular galaxies, and each one is unique in shape, age and structure. Irregular galaxies are often chaotic in shape, with no central bulge or spiral arms.
Do irregular galaxies have a disk?
Irregular galaxies have a disk, but no spiral arms. However, these galaxies do have a mixture of old and young stars combined with a large amount of gas and dust.
What are the characteristics of an irregular galaxy?
An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence , and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure.
What are facts about irregular galaxies?
Some irregular galaxies were once spiral or elliptical galaxies but were deformed by an uneven external gravitational force. Irregular galaxies may contain abundant amounts of gas and dust. This is not necessarily true for dwarf irregulars. Irregular galaxies are commonly small, about one tenth the mass of the Milky Way galaxy.
What are the names of irregular galaxies?
An Irr-I galaxy ( Irr I) is an irregular galaxy that features some structure but not enough to place it cleanly into the Hubble sequence.