A Japanese amateur astronomer has captured what appears to be the second meteor strike on Jupiter in three months.
Masayuki Tachikawa captured video of a small but bright flash on Jupiter's surface. at 18.22 (UT) on August 20. The sighting was confirmed by another Japanese astronomer 500 miles away, Aoki Kazuo. This pretty much eliminates the possiblity that it was a camera glitch or, say, a reflection off an object nearer Earth.
"It seems to me that this is similar to that observed on June 3 this year," says Junichi Watanabe of the National Astronomical Observatory of Japan. That impact was captured by amateurs Anthony Wesley and Christopher Go in Australia and the Philippines respectively.
The flash, which lasted around two seconds, was located on the northern edge of Jupiter's North Equatorial Belt, at around 17° north and System II longitude 140°.
One rotation later, there was no sign of change at the location of the flash, implying that the meteor probably burned up in the upper atmosphere. This indicates that the meteor was comparatively small, probably less than a kilometer wide.
"June 3, August 20, that's a rate of roughly four of these per year," says Emily Lakdawalla of the Planetary Society. She says it may be the case that such impacts are actually very common, but that most simply go unobserved.
"This actually is a perfect example of why amateur astronomers remain relevant and important in astronomy," she says.
"No professional telescope is going to be hanging around shooting video of Jupiter night after night, but you don't need an enormous professional telescope to discover the latest Jupiter impact, or to watch the changes and motions in its belts and storms."