Dvärggalaxer

Dvärggalaxer are small galaxies that contain only a few million to a few billion stars, a stark contrast to the hundreds of billions of stars found in larger galaxies like the Milky Way. They are the most common type of galaxy in the universe, though their low luminosity makes them difficult to detect. Dvärggalaxer are often found orbiting larger galaxies, where they can be tidally disrupted and eventually absorbed. Their formation and evolution are key areas of study in understanding the large-scale structure of the universe.

There are several types of dvärggalaxer, including dwarf spheroidals, dwarf ellipticals, and dwarf irregulars, each with distinct morphologies and stellar populations. Dwarf spheroidals are smooth and featureless, lacking gas and dust, while dwarf irregulars are clumpy and actively forming stars. Dwarf ellipticals fall somewhere in between. Their low metallicity, meaning they have a lower abundance of elements heavier than hydrogen and helium, suggests they are some of the oldest structures in the cosmos, potentially formed early in the universe's history. Studying dvärggalaxer helps astronomers test cosmological models and understand the processes that lead to galaxy formation and growth.