What Is an Irregular Galaxy?
Irregular galaxies are galaxies with irregular shapes, no obvious cores and spiral arms, no disc-shaped symmetrical structure, or no rotational symmetry. The diameter of irregular galaxies is between about 65,500 and 29,000 light years. Of the brightest galaxies in the day, irregular galaxies account for only 5%.
- Irregular galaxies were not included in the Hubble sequence at first. Although they are also galaxies, they have neither vortex structure nor elliptical shape. Their appearance is usually chaotic, with no spherically protruding cores and no traces of vortex-like structures. They are thought to account for a quarter of the total number of galaxies. Most irregular galaxies may have been spiral galaxies or elliptical galaxies, but were deformed due to the destruction of gravity.
- There are two main types of irregular galaxies:
- Type I Irregular Galaxies (Irr I): They have some unique and simple structures, but they are still not enough to be galaxies in the Hubble sequence classification. If there are some vortex structures in the sub-classification of Gérard de Vaucouleurs, they will be classified as Sm, otherwise they will be classified as Im.
- Type II Irregular Galaxy (Irr II): This type of galaxy does not have any identifiable features or structure, which is enough for them to be included in the classification of the Hubble sequence.
- The third type of irregular galaxies are dwarf irregular galaxies (dIrrs or dI). They are faint blue galaxies found in Hubble s deep space exploration. They may only represent local (and Recent) phenomenon. This type of galaxy is now considered to be a very important link in understanding the overall evolution of galaxies. These galaxies have low metal content, but relatively high gas composition, and are considered to be closer to galaxies formed in the early universe.
- Some irregular galaxies were originally small spiral galaxies because the structure of the vortex was destroyed by the gravity of neighboring galaxies.
- The Large Magellanic Cloud was once classified as an irregular galaxy, but now has a structure of rod vortices, so it has been reclassified as the fourth type of rod spiral galaxy (SBm).
- Irregular galaxies were not included at first
- The diameter of irregular galaxies is between about 65,500 and 29,000 light years .
- Of the brightest galaxies in the day, irregular galaxies account for only 5%. Classification by galaxy, irregular stars
- According to the classification of galaxies, there are two main types of irregular galaxies:
- The third type of irregular galaxies are dwarf irregular galaxies (dIrrs or dI). They are faint blue galaxies found in the Hubble Ultra Deep Space Exploration. They may only represent local (and recent) )The phenomenon.
- Some irregular galaxies were originally small spiral galaxies because the structure of the vortex was destroyed by the gravity of neighboring galaxies.
- Irregular galaxy
- IC1613
- IC10
- Leo A
- M82 (Cigar Galaxy)
- NGC1569
- NGC3109
- Pegasus Dwarf Irregular Galaxy
- Phoenix dwarf galaxy
- Dwarf Irregular Galaxy
- Sextant Block A
- Wolf-Lundmark-Merlotti Galaxy (WLM)
- The shapes of irregular galaxies are diverse. We can roughly divide five kinds of elliptical galaxies, lens galaxies, spiral galaxies, rod spiral galaxies and irregular galaxies. The distribution of galaxies in space is not uniform, and often clusters. Less three or two are in groups, and more may be hundreds. This group is also called "galaxy cluster".
- Many areas of the universe are not absolute vacuums, and interstellar space is filled with interstellar matter. The distribution of interstellar matter is very uneven. Among the regions with a high density of cosmic dust matter (this density is still much lower than the laboratory vacuum on the earth), what is observed are fog-like spots called nebulae. There are two kinds of "bright nebula" and "dark nebula". [3]