Astronomers have examined the Extreme Outer Galaxy, also known as the outskirts of our Milky Way galaxy, using the NASA/ESA/CSA James Webb Space Telescope. Located over 58,000 light-years from the galactic center, this region is a firecracker show of star formation.
Thanks to Webb’s near- and mid-infrared imaging capabilities, scientists imaged selected regions within two molecular clouds known as Digel Clouds 1 and 2. The instruments’ high sensitivity and sharp resolution allowed scientists to resolve these areas, which are the birthplace of star clusters undergoing bursts of star formation, in unprecedented detail.
Digel Clouds in our galaxy are relatively poor in elements heavier than hydrogen and helium. Their composition is similar to that of dwarf galaxies and our own Milky Way in its early history. Using Webb, scientists captured the activity in four clusters of young stars within Digel Clouds 1 and 2: 1A, 1B, 2N, and 2S.
In Cloud 2S, the Webb telescope captured a cluster with many young stars. This region is very active, with several stars shooting long jets of material from their poles. Webb’s images also confirmed the presence of a sub-cluster within the cloud for the first time, showing multiple jets spreading out in various directions.
The data reveal some of the details of the clusters’ components, such as very young protostars, outflows and jets, and distinctive nebular structures.
The Webb observations allowed scientists to study star formation in the outer Milky Way at the same level of detail as observations of star formation in our solar neighborhood.
The Webb images of the Extreme Outer Galaxy and the Digel Clouds are just the beginning for the research team. They plan to return to this distant part of the Milky Way to study star clusters and measure the number of stars of different masses. This will help them understand how the environment affects star formation. Although the story of how stars form is complex and not fully understood, Webb provides essential clues to help solve this mystery.
Journal Reference:
- Izumi, Natsuko; Ressler, Michael E et al. Overview Results of JWST Observations of Star-forming Clusters in the Extreme Outer Galaxy. Astronomical Journal. DOI: 10.3847/1538-3881/ad4e2e
