A new discovery is changing how scientists think about how stars and planets are formed. When a star is born, it’s usually surrounded by a spinning disk of gas and dust.
Over time, this disk helps form planets, including rocky ones like Earth.
Until now, scientists believed that these disks gradually shrink as they feed material into the young star and growing planets.
But a new study led by Professor Paolo Padoan has found that these disks might actually grow bigger over time—thanks to a process called Bondi-Hoyle accretion.
Professor Padoan explains that stars are usually born in large groups, deep within huge clouds of gas. Even after a star forms, it can remain in this environment for millions of years.
During this time, the star can continue to pull in material from the surrounding gas cloud.
While this extra material doesn’t add much to the star’s size, it can add a lot to its surrounding disk, helping it become larger and longer-lasting than previously thought.
The team used powerful computer simulations and theoretical models to explore how stars interact with their surroundings. One key part of this process is understanding how the chaotic motion of interstellar gas—known as turbulence—affects how much material a star can gather.
Their findings show that Bondi-Hoyle accretion not only adds more mass to the disk but also provides enough spin, or angular momentum, to explain the large sizes of planet-forming disks seen in space.
These results match real-world observations from ALMA, one of the world’s most advanced radio telescopes. Researcher Veli-Matti Pelkonen, a member of the study team, says that comparing simulations with telescope data is essential to make sure the models reflect reality.
The simulations also allow scientists to explore details that can’t be directly seen, like gas motion and magnetic fields.
This discovery solves a long-standing puzzle about why some protoplanetary disks are so large and suggests that many young stars go through a late growth stage by pulling in extra material.
It also opens the door to new ideas about how and where planets—possibly even habitable ones—can form. As telescopes and computers continue to improve, scientists hope to uncover even more secrets about how stars and planetary systems come to life.
Source: KSR.
