Glowing cosmic cloud reveals cataclysmic collision

Astronomers have long seen evidence of giant, planetary collisions in the universe. In a new study, the evidence of such an impact comes from a cloud of dust and gas with a strange, fluctuating luminosity.

While observing a young (300-million-year-old) Sun-like star, researchers noticed that the star suddenly and significantly dipped in brightness. Looking a little closer, the team found that, just before this dip, the star displayed a sudden spike in infrared luminosity.

This star was first detected in 2021 by the ground-based robotic survey ASAS-SN (All-Sky Automated Survey for Supernovae) while this study was conducted using archival data from NASA's now-retired WISE mission.

The culprit behind both the spike in infrared luminosity and the eclipse was a giant, glowing cloud of gas and dust. The researchers believe that a cosmic collision between two exoplanets (planets beyond our solar system), one of which likely contained ice, was the most likely reason for the sudden, eclipse-causing cloud.

The team suggests that two giant exoplanets crashed into one another, creating both the infrared spike and the cloud. A crash of this magnitude would completely liquify the two planets, leaving behind a single molten core surrounded by a cloud of gas, hot rock, and dust, the researchers said.

Following this cataclysmic collision, this cloud, still holding the hot, glowing remnant of the crash, continued to orbit the star, eventually moving in front of and eclipsing it.

While this data revealed remnants of this planetary collision, telescopes like NASA's James Webb Space Telescope should be able to see the glow of this crash.

Their findings were published in the journal Nature in October 2023.

📣 Discovery Alert! 📣 A dramatic change in a star's luminosity was caused by a giant, glowing cloud of dust. And the likely cause? A cataclysmic crash of two giant exoplanets, leaving behind the cloud and one single molten core, still orbiting the star. https://t.co/rZXJ6kZd6s pic.twitter.com/Egpo1tHaaN

— NASA Exoplanets (@NASAExoplanets) November 16, 2023