OCT 11, 2023 3:50 PM PDT

Astronomers Discover Spectacular Collision Between Ice Giant Exoplanets

A recent study published in Nature examines how the collision of two giant exoplanets resulted in a dust cloud blocking its sun-like star, causing observations to indicate its brightness had dimmed for a period. The star’s brightness was first observed to double in size in infrared wavelengths followed by the brightness drastically reducing in visible light. This study was conducted by an international team of astronomers and holds the potential to help scientists better understand the formation and evolution of young star systems, as this star, named ASASSN-21qj, is only 300 million years old.

Artist illustration of the result of two exoplanets colliding. Fragments of dust and rock speed away from the collision (foreground) and astronomers hypothesize this material will eventually cross in between Earth and the parent star (background). (Credit: Mark Garlick)

“To be honest, this observation was a complete surprise to me,” said Dr. Matthew Kenworthy, who is an associate professor at Leiden University and a co-author on the study. “When we originally shared the visible light curve of this star with other astronomers, we started watching it with a network of other telescopes. An astronomer on social media pointed out that the star brightened up in the infrared over a thousand days before the optical fading. I knew then this was an unusual event.”

The intense brightness was followed by intense dimming that lasted for approximately 1,000 days, followed by an optical eclipse of the star that lasted for approximately 500 days, the latter of which occurred approximately 2.5 years after the initial observation of intense brightness. The team concluded the star’s intense brightness increase and subsequent dimming was caused by a massive dust cloud produced from the collision of two exoplanets with masses ranging from a few Earths to tens of Earth and orbit between 2 to 16 astronomical units (AU) from its star.

“Our calculations and computer models indicate the temperature and size of the glowing material, as well as the amount of time the glow has lasted, is consistent with the collision of two ice giant exoplanets,” said Dr. Simon Lock, who is a Research Fellow in Earth Sciences at the University of Bristol and a co-author on the study.

Going forward, the team hypothesizes the dust cloud will begin to smear along the orbit of the colliding bodies, which could then be detected from both ground- and space-based telescopes, including NASA’s James Webb Space Telescope (JWST). Learning more about this system could provide insights into the formation and evolution of young solar systems throughout the cosmos.

What new discoveries will astronomers make about colliding exoplanets in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

Sources: Nature, EurekAlert!

About the Author
Master's (MA/MS/Other)
Laurence Tognetti is a six-year USAF Veteran who earned both a BSc and MSc from the School of Earth and Space Exploration at Arizona State University. Laurence is extremely passionate about outer space and science communication, and is the author of “Outer Solar System Moons: Your Personal 3D Journey”.
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