New detections of candidate moons suggest that the king of planets could have hundreds of smaller satellites.
© Damian PeachGanymede and Europa, the largest and smallest of Jupiter's four Galilean moons, cast their shadows on Jupiter. The newly discovered detections reported here are evidence of much smaller moons in farther-out orbits.
They will present their findings on September 25th at the virtual
Europlanet Science Congress 2020. Most of the moons are in wide, irregular, and retrograde orbits.
Over the past 20 years, astronomers have found dozens of small Jovian moons thanks to the advance of large digital cameras. Back in 2003, Scott Sheppard (Carnegie Institution of Science) already estimated that the number of irregular moons larger than a kilometer would probably be around one hundred.
Now, Edward Ashton, Matthew Beaudoin, and Brett Gladman (University of British Columbia, Vancouver)
have detected about four dozen possible new Jovian moons that are even smaller. Extrapolating from the sky area they have searched (about one square degree), they conclude that there could be some 600 of these tiny objects orbiting the giant planet.The team studied 60 archival 140-second exposures of a field close to Jupiter, all of them taken within a 3-hour period on September 8, 2010, with the 340-megapixel
MegaPrime camera at the Canada-France-Hawai'i Telescope on Mauna Kea. The astronomers digitally combined the images in 126 different ways, one for every possible combination of speed and direction at which a potential Jovian moon might move across the sky.
Comment: Last month a rare Type II Gigantic Jet event was recorded over Tropical Storm Laura.