A fireworks display of star formation is taking place on the outskirts of the Milky Way. The James Webb Space Telescope has explored the outskirts of our Milky Way galaxy, and its near- and mid-infrared imaging capabilities have allowed scientists to study a star formation region that resembles our galaxy in the early stages of its formation.
The outermost outer galaxy
Astronomers have sent the James Webb Space Telescope to explore the outskirts of our Milky Way galaxy, a region that scientists call the Outermost Outer Galaxy because of its location more than 58 thousand light-years from the center of the Galaxy. For comparison, the Earth is about 26 thousand light-years from the center.
The team of scientists used the NIRCam (Near Infrared Camera) and MIRI (Mid-Infrared Instrument) to photograph separate regions in two molecular clouds known as the Diegel Clouds 1 and 2. Thanks to its high sensitivity and sharp resolution, Webb was able to distinguish these regions, which contain star clusters undergoing star formation bursts, in unprecedented detail. Some of the details revealed by these data include cluster components such as very young protostars (class 0), outflows and jets, and characteristic nebulae.
These observations by Webb allow scientists to study star formation in the outer Milky Way at the same level of detail as observations of star formation in our own solar neighborhood. These results were published in the Astronomical Journal.
Stars in the making
Although the Diegel Clouds are within our galaxy, they are relatively poor in elements heavier than hydrogen and helium. This composition makes them similar to dwarf galaxies and our Milky Way in its early history. The team therefore took the opportunity to use Webb to record activity in four clusters of young stars in the Diegel Clouds 1 and 2: 1A, 1B, 2N, and 2S.
In Cloud 2S, Webb recorded the main cluster containing young, recently formed stars. This dense region is quite active, with several stars emitting long jets of matter along their poles. In addition, although scientists had previously suspected that a subcluster cluster might be present in the cloud, Webb’s imaging capabilities have confirmed its existence for the first time. The Webb data show that numerous jets are flying out of this cluster of stars in different directions.
A saga of stars
This Webb image of the Outermost Outer Galaxy and the Digel Clouds is just the starting point for the team. They intend to return to this outpost of the Milky Way to find answers to a variety of ongoing questions, including the relative number of stars of different masses in the star clusters of the Outermost Outer Galaxy, a measurement that will help astronomers understand how a particular environment may affect different types of stars during their formation.
Although the history of star formation is complex and some parts of it are still shrouded in mystery, Webb is collecting clues and helping astronomers unravel this intricate story.
