Astronomers were taken by surprise: unusual small galaxies have puzzled scientists (photo).

Astronomers have uncovered something remarkable about the smallest and faintest class of galaxies in the universe, known as ultra-diffuse galaxies. Researchers found that approximately half of these galaxies exhibit movement patterns that challenge previous theories regarding the formation and evolution of such objects. Specifically, astronomers discovered unexpected rotational motion of stars within many of these dwarf galaxies. The study is published in the journal Astronomy & Astrophysics, reports Space.

According to astronomers, they not only managed to observe the movements of stars in these galaxies but also discovered unexpected phenomena. To investigate these unusual galaxies, scientists utilized the powerful ground-based VLT telescope. Ultra-diffuse galaxies were first identified relatively recently, but the process of their creation and development, given their extremely low luminosity, quickly became a mystery for astronomers.

The new research revealed that members of the smallest class of galaxies exist in environments that vary significantly in their properties, the amount of dark matter they contain, as well as the movements and compositions of their stars. In particular, astronomers conducted a detailed study of the ultra-diffuse galaxy UDG32, which is located at the end of a gas filament extending from the spiral galaxy NGC 3314A.

One theory explaining the origin of ultra-diffuse galaxies suggests that they form when gas filaments are expelled from larger galaxies due to gravitational interactions with other objects. If molecular gas clouds remain within these filaments, they can become exceedingly dense and collapse under their own gravity. This process leads to the formation of stars, which become the foundation of these unusual dwarf galaxies.

New observations confirmed that the connection between UDG32 and the gas filament of NGC3314A is not merely a result of random alignment. Additionally, astronomers found that this ultra-diffuse galaxy contains more heavy chemical elements, which are heavier than hydrogen and helium, compared to other similar objects in the Hydra galaxy cluster.

Heavy chemical elements are created in the cores of stars through nuclear fusion and are released into space when stars die, thus providing the building blocks for the next generation of stars. However, astronomers discovered that the stars in UDG32 are younger than those in other ultra-diffuse galaxies within the Hydra galaxy cluster, yet they possess a significantly higher concentration of heavy chemical elements.

According to astronomers, this indicates that these stars were formed in gas clouds enriched with heavy elements, which were expelled by a larger and older galaxy. This supports the idea that UDG32 was formed due to interactions with a neighboring spiral galaxy.