‘Cataclysmic’ collision of giant asteroids discovered in nearby star

Scientists have found evidence of a “cataclysmic” collision of giant asteroids that happened only 20 years ago close to a nearby star.

The tumultuous event in Beta Pictoris, a bright star in the constellation of Pictor around 63 light-years away, could help understand how planets like Earth formed, astronomers say.

Scientists have been studying this star system, which is a mere 20 million years old, for more than three decades.

But the latest data from the James Webb Space Telescope – launched in 2021 as part of a joint mission between Nasa, European Space Agency and the Canadian Space Agency – showed some of dust surrounding Beta Pictoris, which was recorded in previous observations, had disappeared.

Christine Chen, an astronomer at Johns Hopkins University in the US who led the research, said: “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.”

The team said this collision would have occurred just before another Nasa telescope, Spitzer, gathered data from the region between 2004 and 2005.

Two different space telescopes – Spitzer and JSWT – took snapshots 20 years apart of the same area around the star Beta Pictoris which is 63 light-years away (Roberto Molar Candanosa/Johns Hopkins University, with Beta Pictoris (Roberto Molar Candanosa/Johns Hopkins University/Lynette Cook/Nasa)
Two different space telescopes – Spitzer and JSWT – took snapshots 20 years apart of the same area around the star Beta Pictoris which is 63 light-years away (Roberto Molar Candanosa/Johns Hopkins University, with Beta Pictoris (Roberto Molar Candanosa/Johns Hopkins University/Lynette Cook/Nasa)

The violent clashes would have crushed some of the larger space rocks into fine dust particles smaller than pollen or powdered sugar, the researchers said.

And the amount of dust generated would have been about 100,000 times the size of the asteroid that killed the dinosaurs, they added.

In the aftermath of the explosion, Spitzer’s instruments were able to identify the dust closet to the star by looking at their heat signatures.

But gradually, this dust started to cool off as it moved far enough away from the star to become undetectable by JWST two decades later.

Cicero Lu, a former PhD student in astrophysics at Johns Hopkins University, said: “Most discoveries by JWST come from things the telescope has detected directly.

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

Surrounded by a disk of dust and debris, Beta Pictoris is at an age where giant planets – Beta Pic b and c – have formed but rocky planets like Earth might still be developing.

The researchers said the findings, presented at the 244th Meeting of the American Astronomical Society in the US, offer a “unique glimpse” into how the Solar System came into existence more than four billion years ago.

Kadin Worthen, a PhD student in astrophysics at Johns Hopkins University, said the main question scientists are trying to answer is whether the Solar System is unique or are there similar planetary systems out there.

He said: “We are trying to understand how weird or average we are.”

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