Tucson Standard

Researchers at the University of Arizona have discovered that planet-forming disks can last significantly longer than previously thought, particularly around small stars. These findings challenge existing assumptions about the lifespan of these cosmic structures, which typically last around 10 million years.

The study, led by Feng Long from the Lunar and Planetary Laboratory at the University of Arizona, reveals a protoplanetary disk that has persisted for 30 million years. The research was published in the Astrophysical Letters Journal and utilized NASA's James Webb Space Telescope to conduct a detailed chemical analysis.

"In a sense, protoplanetary disks provide us with baby pictures of planetary systems, including a glimpse of what our solar system may have looked like in its infancy," said Long.

The team observed a star known as J0446B in the constellation Columba, located about 267 light-years from Earth. The planet-forming disk around this star has lasted much longer than expected. "Although we know that most disks disperse within 10 million to 20 million years, we are finding that for specific types of stars, their disks can last much longer," Long explained.

The research found that even though tiny stars retain their disks longer, the chemical composition remains relatively unchanged over time. This stability could allow more time for planets to form around low-mass stars.

Chengyan Xie, a doctoral student at LPL who contributed to the study, noted: "We detected gases like hydrogen and neon, which tells us that there is still primordial gas left in the disk around J0446B."

The existence of long-lived disks rich in gases has implications for life outside our solar system. The TRAPPIST-1 system is of particular interest due to its potential habitability and similar mass category to stars with long-lived disks.

Ilaria Pascucci, a professor of planetary sciences at LPL who co-authored the study, commented on TRAPPIST-1: "To make the specific arrangement of orbits we see with TRAPPIST-1, planets need to migrate inside the disk, a process that requires the presence of gas."

Long-lived disks have not been found for high-mass stars like our sun because they evolve more quickly. However, understanding low-mass star systems could help fill gaps in our knowledge about planetary formation across the universe.

"Developing a better understanding of how low-mass star systems evolve and getting snapshots of long-lived disks might help pave the way to filling out the blanks in the photo album of the universe," Long concluded.