Last October, professional astronomers spotted a bright flash on Jupiter. Something hit the largest planet in the solar system, releasing the equivalent of two megatons of TNT worth of energy, comparable to the Tunguska impact that rocked Siberia in 1908. This was the most powerful known impact Jupiter has received since comet Shoemaker-Levy 9 smacked the planet in 1994.
The paper is available on the science paper repository ArXiv (pronounced archive) and it is accepted for publication in The Astrophysical Journal Letters.
The impact took place on October 15, 2021, and it was observed by Planetary ObservatioN Camera for Optical Transient Surveys (PONCOTS), which is operated by the University of Kyoto. This is the first time a dedicated observatory snapped the observations. Excluding the comet, previous impacts were spotted serendipitously by amateur astronomers, so having an ad-hoc facility allows for some incredible science.
For example, the team was able to estimate that the impactor had a mass of about 4.1 million kilograms (~9 million pounds), which would be like slamming a couple of space shuttles at really high velocity in the tempestuous atmosphere of the King of the Planets.
Based on the estimate of the mass, the bolide might have been roughly between 15 to 30 meters (50 to 100 feet) across. Not that big in the grand scheme of things, but speeding enough to heat up to 8,000°C (14,400°F). This is interesting because it provides insight into the kind of body it might have been. Collecting data on these planetary collisions far from Earth could help us prepare for when a comet or asteroid will come tumbling down on our heads. Given that we remain uncertain exactly what happened at Tunguska.
The observation appeared to be ten times brighter than previous amateur observations of impacts. And it also allowed the researchers to estimate how often these kinds of impacts are likely to happen on Jupiter. Turns out a lot more often than on Earth. Between 100 and 1,000 times more often, so roughly they’d have a Tunguska-like event once a year.
The team plans to launch a long-term monitoring campaign of Jupiter with an upgraded version of their PONCOTS system.
"Since the original PONCOTS system is a prototype, it does not support a remote observation mode that is essential for long-term monitoring," lead author Dr Ko Arimatsu told IFLScience. "The next generation PONCOTS system will support such mode and achieve detections of other impact flashes."
[H/T: New Scientist]