May 10, 2024

Cosmic Crash! Afterglow of Massive Planetary Collision Captured for the First Time

Image reveals a visualization of the huge, glowing planetary body produced by a planetary collision. In the foreground, fragments of ice and rock fly away from the crash and will later cross in between Earth and the host star which is seen in the background of the image. Credit: Mark Garlick
Researchers observed two ice giant exoplanets clashing around a sun-like star, triggering an intense burst of light and dust. This discovery, made by a worldwide team of astronomers, could cause the development of new moons around a newly-formed planet in the future.
The research study, released today (October 11) in Nature, reports the sighting of 2 ice huge exoplanets colliding around a sun-like star, developing a blaze of light and plumes of dust. Its findings reveal the brilliant heat afterglow and resulting dust cloud, which relocated front of the moms and dad star dimming it with time.
A Collaborative Observation Effort
The worldwide group of astronomers was formed after a lover viewed the light curve of the star and noticed something unusual. It revealed the system doubled in brightness at infrared wavelengths some three years before the star started to fade in visible light.

Co-lead author Dr. Matthew Kenworthy, from Leiden University, stated: “To be sincere, this observation was a complete surprise to me. When we originally shared the visible light curve of this star with other astronomers, we began viewing it with a network of other telescopes.
” An astronomer on social media mentioned that the star illuminated in the infrared over a thousand days before the optical fading. I knew then this was an uncommon event.”
A simulation of an accident in between two ice giant bodies showing the simulation particles (top) and density (bottom) in a slice through the midplane of the effect. The scale bar broadens throughout the simulation to follow the expanding post-impact body and debris. Credit: University of Bristol
Star Monitoring and Interpretation
The network of expert and amateur astronomers studied the star intensively consisting of tracking changes in the stars brightness over the next two years. The star was named ASASSN-21qj after the network of telescopes that initially identified the fading of the star at noticeable wavelengths.
The researchers concluded the most likely explanation is that two ice giant exoplanets collided, producing the infrared radiance detected by NASAs NEOWISE objective, which uses a space telescope to hunt for asteroids and comets.
Insights from Co-Lead Researchers
Co-lead author Dr. Simon Lock, Research Fellow in Earth Sciences at the University of Bristol, said: “Our computations and computer system designs indicate the temperature level and size of the radiant product, along with the amount of time the radiance has actually lasted, is constant with the crash of 2 ice giant exoplanets.”
The resultant expanding debris cloud from the impact then traveled in front of the star some 3 years later, causing the star to dim in brightness at noticeable wavelengths.
Future Observations and Predictions
Over the next couple of years, the cloud of dust is expected to begin smearing out along the orbit of the accident remnant, and a telltale scattering of light from this cloud could be identified with both ground-based telescopes and NASAs biggest telescope in space, known as JWST.
The astronomers intend on enjoying carefully what occurs next in this system.
Co-author Dr. Zoe Leinhardt, Associate Professor of Astrophysics at the University of Bristol, added: “It will be fascinating to observe additional advancements. Eventually, the mass of product around the residue may condense to form a retinue of moons that will orbit around this new world.”
Recommendation: “A planetary crash afterglow and transit of the resultant particles cloud” by Matthew Kenworthy, Simon Lock, Grant Kennedy, Richelle van Capelleveen, Eric Mamajek, Ludmila Carone, Franz-Josef Hambsch, Joseph Masiero, Amy Mainzer, J. Davy Kirkpatrick, Edward Gomez, Zoë Leinhardt, Jingyao Dou, Pavan Tanna, Arttu Sainio, Hamish Barker, Stéphane Charbonnel, Olivier Garde, Pascal Le Dû, Lionel Mulato, Thomas Petit and Michael Rizzo Smith, 11 October 2023, Nature.DOI: 10.1038/ s41586-023-06573-9.

Image shows a visualization of the big, glowing planetary body produced by a planetary collision. In the foreground, fragments of ice and rock fly away from the collision and will later on cross in between Earth and the host star which is seen in the background of the image. A simulation of an accident in between 2 ice giant bodies revealing the simulation particles (top) and density (bottom) in a slice through the midplane of the effect. The scale bar broadens throughout the simulation to follow the expanding post-impact body and debris. Credit: University of Bristol