For the first time, an international group of astronomers have seen the heat glow of two ice giant planets colliding, and the resultant dust cloud then move in front of the parent star several years later. The star ASASSN-21qj—named after the network of telescopes that first detected the fading of the star at visible wavelengths—was then studied intensively by a network of amateur and professional astronomers including Dr. Matthew Kenworthy at Leiden Observatory (the Netherlands), who monitored the changes in the star's brightness over the next two years.
