Young stars do much more than simply light up the night sky.
According to new research, they begin changing the future of their entire galaxies almost as soon as they are born.
By releasing enormous amounts of energy into the surrounding gas, these stars can influence where new stars form, how galaxies grow and even how their structures develop over time.
The findings were presented at the 248th meeting of the American Astronomical Society and are based on observations from the Atacama Large Millimeter/submillimeter Array (ALMA), the James Webb Space Telescope and the Hubble Space Telescope.
The data came from the international Physics at High Angular Resolution in Nearby GalaxieS (PHANGS) collaboration, which studies how nearby galaxies form, evolve and create new stars.
The research team examined about 18,000 star-forming regions across nearby spiral galaxies. These are the dense clouds of gas and dust where new stars are born. By combining observations from several powerful telescopes, the scientists were able to study these stellar nurseries in much greater detail than before.
The researchers found that newly formed massive stars quickly begin affecting their surroundings. As these young stars produce intense radiation, they heat nearby gas and strip electrons from atoms, creating ionized gas. This hot, energized gas expands outward and pushes against the surrounding clouds, causing star-forming regions to grow.
Lead researcher Debosmita Pathak, a graduate student in astronomy at The Ohio State University, explained that this pressure from ionized gas is the main force driving the expansion of star-forming regions in typical galaxies. However, whether those regions continue expanding or eventually stop depends heavily on the environment around them.
This process is known as stellar feedback. It is one of the most important mechanisms controlling how galaxies evolve. In some cases, the expanding gas compresses nearby clouds, helping new stars to form. In other situations, it pushes gas away so effectively that it removes the raw material needed to create future stars, slowing or even stopping star formation.
To better understand how stellar feedback changes under more extreme conditions, the researchers compared ordinary spiral galaxies with NGC 3256, a galaxy created by the collision of two galaxies. Galaxy mergers are among the most violent events in the universe and often trigger bursts of rapid star formation.
The team discovered that the pressure produced by stellar feedback inside NGC 3256 is about 100 times greater than in galaxies similar to the Milky Way. This creates a much more chaotic environment where gas is constantly being stirred, compressed and scattered, making star formation far less predictable.
According to the researchers, these measurements provide valuable information about physical conditions that have been difficult to study until now. Understanding how stellar feedback behaves in both calm and violent galaxies will help scientists build more accurate computer models of galaxy evolution.
One of the most significant findings is that young stars begin reshaping their galaxies long before they reach the dramatic end of their lives as supernova explosions. Their energy alone is enough to influence the movement of gas, the birth of future stars and the overall development of galaxies across billions of years.
The study offers an important new piece of the puzzle of how galaxies change over cosmic time and demonstrates that even the youngest stars play a powerful role in shaping the universe around them.
Source: National Radio Astronomy Observatory.
