Two giant planets collide in space. Earth picks up the cosmic dust

In a collaboration between professional and amateur astronomers, a remarkable discovery has been made: a glowing cloud of dust resulting from a colossal planetary collision.

This celestial event was captured thanks to the keen observations of NASA volunteers and has been detailed in a recent Nature paper.

The cosmic drama unfolded around a star named Asassn-21qj, located some 1800 light-years away from Earth. The All-Sky Automated Survey for Supernovae (ASAS-SN) network first detected an unusual fading of this sun-like star back in 2021.

Approximately a month later, NASA volunteer Arttu Sainio, while browsing X (formerly known as Twitter), noticed a discussion by professional astronomers Dr. Matthew Kenworthy and Dr. Eric Mamajek about this peculiar occurrence.

Intrigued, Sainio delved into data from NASA’s NEOWISE mission and discovered that the star had experienced an unexpected brightening in infrared light two years prior to the optical dimming.

This finding, shared on social media, caught the attention of Kenworthy, who recognized the significance of the event. The collaborative effort expanded with contributions from amateur spectroscopist Hamish Barker, who attempted to capture the star's spectrum in July 2022 but found it too faint.

He then reached out to the French amateur astronomy team, the Southern Spectroscopic project Observatory Team (2SPOT), which includes Stephane Charbonnel, Pascal Le Dû, Olivier Garde, Lionel Mulato, and Thomas Petit.

In September 2022, 2SPOT successfully obtained the spectrum and sent it to Kenworthy for analysis.

Further independent observations came from amateur astronomers Sean Curry, who provided a spectrum in April 2023, and Dr. Franz-Josef (Josch) Hambsch, who monitored Asassn-21qj from his ROAD observatory in the Atacama Desert, submitting his findings to the American Association of Variable Star Observers (AAVSO) database.

This collective effort not only highlights the significant role of citizen scientists in advancing astronomical research but also underscores the potential of collaborations between professionals and enthusiasts.

The discovery of the aftermath of two ice giant planets colliding, evidenced by the heat glow and subsequent dust cloud, marks a significant milestone in our understanding of cosmic events and the dynamic nature of the universe.