(small galaxy with a few billion stars)
The term Dwarf Galaxy is used for galaxies much smaller
than the Milky Way, i.e.,
of a few billion stars at most, and as small as 100 parsecs
across. They can be any of the normal galaxy types, such as a
Often they are Satellite Galaxies.
Some more specific terms:
- Blue Compact Dwarf Galaxy - with young hot stars.
- Ultra-Compact Dwarf Galaxy - in the 100-Parsec range.
- Hobbit Galaxy - small, faint dwarf galaxy.
Examples (in Local Group):
David Dunlap Observatory Catalog (DDO)
Hierarchical Assembly of Galaxies
I Zwicky 18 (I Zw 18)
Local Group (LG)
Low-Surface-Brightness Galaxy (LSB Galaxy)
TiNy Titans (TNT)
Triangulum II (Tri II)
Ultra-Faint Dwarf Galaxy (UFD)