Ultra-compact Dwarfs
Ultra-compact dwarf galaxies (UCD) are a recently discovered class of very compact galaxies with very high stellar population counts. They are thought to be on the order of 200 light years across, with a hundred million stars. It is theorized that these are the cores of nucleated dwarf elliptical galaxies, that have been stripped of gas and outlying stars by tidal interactions, travelling through the hearts of rich clusters. UCDs have been found in the Virgo Cluster, Fornax Cluster, Abell 1689, Coma Cluster, amongst other clusters.
Dwarf galaxies come in other morphologies as well:
- Elliptical galaxy: dwarf elliptical galaxy (dE) and its subtype dwarf spheroidal galaxy (dSph)
- Irregular galaxy: dwarf irregular galaxy (dI)
- Spiral galaxy: dwarf spiral galaxy (dS)
Read more about this topic: Blue Compact Dwarf Galaxy
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