UVic astronomers uncover new insights into star formation
July 19, 2024 | by Nicole Crozier
New research from the University of Victoria has found that star formation may be twice as efficient as previously thought.
Using an image of a nearby, young, star-forming region known as the Cosmic Cliffs, taken by the James Webb Space Telescope (JWST) in 2022, University of Victoria PhD student Breanna Crompvoets and researchers at the NRC Herzberg Astronomy and Astrophysics Research Centre were able to learn more about the region than previous images from other telescopes had allowed, identifying an increased number of stars and an increase in star formation efficiency. Their research was published on July 9, 2024 in The Astronomical Journal.
“Much of our understanding of how the universe works has been based off old telescope images. Using the old images is like trying to identify your friends in a grainy, dark image taken on an old cell phone—it’s hard to see the details. JWST has a much higher resolution and sensitivity and allows us to see what’s happening out in space much more clearly. This change is hugely impacting our understanding of how stars form.”
- Breanna Crompvoets, PhD student in Astronomy who conducted this research as part of her master's thesis
The Cosmic Cliffs photo shows the cusp of a stellar nursery, where stellar winds cause the movement of gas and dust and trigger the formation of new stars. Crompvoets was able to identify about 20,000 stars in the image and by using machine learning techniques, identified which objects in the image were young and in the process of becoming stars. She found 20 times more forming stars than were previously known.
Stars form out of gas and dust, and it was previously thought that only 5% of gas and dust in a stellar nursery goes on to become a star. However, when Crompvoets compared the amount of gas and dust going into the forming stars she had identified to how much gas and dust was present overall, she found an efficiency as high as 10%.
“The fact that there are more forming stars in this region than we had thought, but the same amount of gas and dust overall, means that stars are forming more efficiently than we thought,” says Crompvoets. “This finding may require us to re-evaluate our understanding of how stars form.”
Along with identifying Sun-like young stars in the Cosmic Cliffs, Crompvoets also discovered a substantial population of very low-mass young stars. These stars will never get big enough to begin the process of hydrogen fusion in their cores. Although these tiny stars make up about 70% of all the young stars identified, it was previously not known that they existed to this degree within star-forming regions. More research is needed to determine if similar populations are found in other regions and determine the role of any potential late-stage major mass gain from the larger environment.
Crompvoets is currently applying her methods to new regions in space to see if the efficiency of star formation is more broadly applicable.