The James Webb Space Telescope (JWST) has captured a dramatic event: two massive asteroids colliding in a nearby star system, offering insights into the formation of solar systems similar to our own.
Illustration: Protoplanetary Disk An artist’s impression of a protoplanetary disk, akin to the one observed by JWST in the Beta Pictoris star system. (Credit: ESO)
The JWST detected evidence of a colossal collision between two giant asteroids in the Beta Pictoris star system, located 63 light-years away in the constellation Pictoris. This impact released 100,000 times more dust than the asteroid impact that led to the extinction of the dinosaurs.
Beta Pictoris: A Young Star System The Beta Pictoris system, only 20 million years old compared to our solar system’s 4.5 billion years, was first discovered in 1983 by NASA’s Infrared Astronomical Satellite (IRAS). It likely formed from the shockwave of a nearby supernova. While the system currently hosts at least two gas giant planets, it lacks known rocky worlds. However, large dust-producing collisions, like the one observed by JWST, suggest that rocky inner planets may still be forming.
Turbulent Beginnings Beta Pictoris’s circumstellar debris disk, a vast ring of gas and dust around the star, is much more tumultuous than our own, providing a unique opportunity for astronomers to study the early stages of planet formation. These findings could shed light on the history of our own solar system.
“Beta Pictoris is at an age when planet formation in the terrestrial planet zone is still ongoing through giant asteroid collisions, so what we could be seeing here is basically how rocky planets and other bodies are forming in real time,” said Christine Chen, lead study author and astronomer at Johns Hopkins University.
Insights from Space Telescopes Two space telescopes captured images of Beta Pictoris 20 years apart. The Spitzer Space Telescope’s 2004-05 images showed a massive dust cloud, which had vanished by the time JWST observed the system in 2023. This indicates a significant asteroid collision occurred around 20 years ago, dispersing vast quantities of dust.
“With Webb’s new data, the best explanation we have is that, in fact, we witnessed the aftermath of an infrequent, cataclysmic event between large asteroid-size bodies, marking a complete change in our understanding of this star system,” Chen explained.
Broader Implications These findings will help astronomers understand the architecture of star systems and how frequently habitable systems like our own form. “The question we are trying to contextualize is whether this whole process of terrestrial and giant planet formation is common or rare, and the even more basic question: Are planetary systems like the solar system that rare?” said Kadin Worthen, a doctoral student in astrophysics at Johns Hopkins University. “We’re basically trying to understand how weird or average we are.”
