NASA images confirm Jupiter impact

NASA images confirm
Jupiter impact
DR EMILY BALDWIN
ASTRONOMY NOW
Posted: July 21, 2009

On the 40th anniversary of the Apollo 11 Moon landing and exactly fifteen years after fragments of Comet Shoemaker-Levy 9 collided with Jupiter, NASA confirms amateur observations of a new spot on the gas giant as the likely result of an impact event.

This image was taken at 1.65 microns, a wavelength sensitive to sunlight reflected from high in Jupiter's atmosphere, and it shows both the bright centre of the scar (bottom left) and the debris to its northwest (upper left). Image: NASA/JPL/Infrared Telescope Facility.

Scientists at NASA's Jet Propulsion Laboratory (JPL) followed up on the observations of Anthony Wesley and others, which we reported on yesterday, using the Infrared Telescope Facility on Hawaii. "We were extremely lucky to be seeing Jupiter at exactly the right time, the right hour, the right side of Jupiter to witness the event. We couldn't have planned it better," says Glenn Orton of JPL.

Images taken in infrared confirm that the likely impact point was in the south polar region of Jupiter, manifesting as a dark 'scar' in visible images. Bright upwelling in the upper atmosphere was detected at near-infrared wavelengths, and a warming of the upper troposphere, along with possible extra emission from ammonia gas, was detected at mid-infrared wavelengths. Ammonia was also churned up by the Shoemaker-Levy 9 impact.

"It could be the impact of a comet, but we don't know for sure yet," says Orton. "It's been a whirlwind of a day, and this on the anniversary of the Shoemaker-Levy 9 and Apollo anniversaries is amazing."

Infrared observations taken at the Keck II telescope in Hawaii reveal a bright spot where the impact occurred. Jupiter's Great Red Spot can be seen at the bottom of the image. Image: Paul Kalas/Michael Fitzgerald/Franck Marchis/UC Berkeley/SETI Institute.

Amateurs and professionals alike will continue to monitor the impact scar to learn more about its origin and to see how it evolves and dissipates over the coming days. At present it is roughly the same size as one of Jupiter's large storms known as Oval BA, or about the same size as our own planet Earth.

"Given the rarity of these events, it's extremely exciting to be involved in these observations," says Leigh Fletcher at JPL. "These are the most exciting observations I've seen in my five years of observing the outer planets!"

Images taken with the Keck II telescope, also in Hawaii, further support the idea of an impact with the gas planet. "The fact that [the feature] shows up so clearly means that it’s associated with high-altitude aerosols as seen in the Shoemaker-Levy impacts," says James Graham of the University of California Berkeley, who also assisted with the observations taken during the Shoemaker-Levy 9 event in 1994. The Keck team are confident that an impact must have created Jupiter’s latest feature.