Researchers at the University of Arizona have made a groundbreaking discovery that challenges our understanding of planet formation. A team led by Feng Long has found that planet-forming disks, also known as protoplanetary disks, can last significantly longer than previously thought – up to 30 million years.
Most planetary nurseries are short-lived, typically lasting only about 10 million years. However, the discovery was made around a small star, WISE J044634.16–262756.1B, which is one-tenth of the sun’s mass or less. The team observed that this star’s planet-forming disk has lasted approximately three times longer than expected.
The researchers used NASA’s James Webb Space Telescope to analyze the chemical composition of the disk and found that it contains primordial gases like hydrogen and neon. This suggests that the disk is still in its early stages of formation, despite its advanced age.
The discovery has significant implications for our understanding of life beyond Earth. The team found that long-lived disks around low-mass stars could provide planets with more time to form. This is particularly interesting for the TRAPPIST-1 system, a red dwarf star with seven planets similar in size to Earth, three of which are located in the habitable zone.
The existence of long-lived disks also sheds light on the evolution of planetary systems. According to the team, the presence of gas in these disks might be responsible for the unique arrangement of orbits seen in TRAPPIST-1.
The discovery was made possible by analyzing a rare type of disk called debris disks, which are typically longer-lasting than protoplanetary disks. The researchers ruled out this possibility by detecting gases in the disk around WISE J0446B.
The study provides new insights into planet formation and the habitability of planets outside our solar system. By studying long-lived disks, scientists can gain a better understanding of how low-mass star systems evolve and develop a more comprehensive picture of the universe.
Feng Long and her team’s findings have been published in The Astrophysical Journal Letters.
Source: https://phys.org/news/2025-03-webb-reveals-planet-disks-longer.html