Aftermath of a “cataclysmic” asteroid collision in neighbouring star system

Astronomers have identified the aftermath of a massive collision between giant asteroids in the Beta Pictoris star system using new data from the James Webb Space Telescope (JWST).

Located about 63 light years from Earth, Beta Pictoris is young compared to our 4.5 billion-year-old solar system at only 20 million years old.

“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,” says Christine Chen, an astronomer at Johns Hopkins University and the Space Telescope Science Institute in the US, who led the research.

Astronomers detected significant changes in the heat emitted by dust grains around Beta Pictoris by comparing new data from JWST to observations by the Spitzer Space Telescope from 2004 and 2005.

“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,” says Chen.

Chen says this pulverising them into fine dust particles smaller than pollen or powdered sugar.

This dust was initially closer to the star and heated up, emitting the thermal radiation that Spitzer’s instruments identified.

However, the new JWST data found no traces of the previously detected particles. This suggested the dust was dispersed outwards by radiation from the system’s central star and has since cooled down.

Scientist previously assumed that other phenomena, like small bodies grinding down, would stir and replenish the dust steadily over time.

“Most discoveries by JWST come from things the telescope has detected directly,” says co-author Cicero Lu, a former Johns Hopkins doctoral student in astrophysics.

“In this case, the story is a little different because our results come from what JWST did not see.”

The findings are presented at the 244th Meeting of the American Astronomical Society in Madison, Wisconsin.

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