SwRI scientists image a bright meteoroid explosion in Jupiter's atmosphere
by Staff Writers
San Antonio TX (SPX) Feb 24, 2021
From aboard the Juno spacecraft, a Southwest Research Institute-led instrument observing auroras serendipitously spotted a bright flash above Jupiter's clouds last spring. The Ultraviolet Spectrograph (UVS) team studied the data and determined that they had captured a bolide, an extremely bright meteoroid explosion in the gas giant's upper atmosphere.
"Jupiter undergoes a huge number of impacts per year, much more than the Earth, so impacts themselves are not rare," said SwRI's Dr. Rohini Giles, lead author of a paper outlining these findings in Geophysical Research Letters. "However, they are so short-lived that it is relatively unusual to see them. Only larger impacts can be seen from Earth, and you have to be lucky to be pointing a telescope at Jupiter at exactly the right time. In the last decade, amateur astronomers have managed to capture six impacts on Jupiter."
Since Juno arrived at Jupiter in 2016, UVS has been used to study the morphology, brightness and spectral characteristics of Jupiter's auroras as the spacecraft cartwheels close to its surface every 53 days. During the course of a 30-second spin, UVS observes a swath of the planet. The UVS instrument has occasionally observed short-lived, localized ultraviolet emissions outside of the auroral zone, including a singular event on April 10, 2020.
"This observation is from a tiny snapshot in time - Juno is a spinning spacecraft, and our instrument observed that point on the planet for just 17 milliseconds, and we don't know what happened to the bright flash outside of that time frame," Giles said, "But we do know that we didn't see it on an earlier spin or a later spin, so it must have been pretty short-lived."
Previously, UVS had observed a set of eleven bright transient flashes that lasted 1 to 2 milliseconds. They were identified as Transient Luminous Events (TLEs), an upper atmospheric phenomenon triggered by lightning. The team initially thought this bright flash might be a TLE, however, it was different in two key ways.
While it was also short-lived, it lasted at least 17 milliseconds, much longer than a TLE. It also had very different spectral characteristics. Spectra of TLEs and auroras feature emissions of molecular hydrogen, the main component of Jupiter's atmosphere. This bolide event had a smooth "blackbody'" curve, which is what is expected from a meteor.
"The flash duration and spectral shape match up well with what we expect from an impact," Giles said. "This bright flash stood out in the data, as it had very different spectral characteristics than the UV emissions from the Jupiter's auroras. From the UV spectrum, we can see that the emission came from blackbody with a temperature of 9600 Kelvin, located at an altitude of 140 miles above the planet's cloud tops. By looking at the brightness of the bright flash, we estimate that it was caused by an impactor with a mass of 550-3,300 pounds."
Comet Shoemaker-Levy was the largest observed Jupiter impactor. The comet broke apart in July 1992 and collided with Jupiter in July 1994, which was closely observed by astronomers worldwide and the Galileo spacecraft. An SwRI-led team detected impact-related X-ray emissions from Jupiter's northern hemisphere, and prominent scars from the impacts persisted for many months.
"Impacts from asteroids and comets can have a significant impact on the planet's stratospheric chemistry - 15 years after the impact, comet Shoemaker Levy 9 was still responsible for 95% of the stratospheric water on Jupiter," Giles said. "Continuing to observe impacts and estimating the overall impact rates is therefore an important element of understanding the planet's composition."
Research Report: "Detection of a bolide in Jupiter's atmosphere with Juno UVS"
Peering at the Surface of a Nearby Moon
Washington DC (SPX) Feb 01, 2021
Among Jupiter's Galilean moons, icy Europa or volcanic Io often take the spotlight - but their sibling moon Ganymede has plenty of secrets to share. Powerful new millimeter observations have now provided insight into this complex satellite's surface. The frozen, alien landscape of Ganymede contains a little of everything. Shadowy regions of ancient, battered dark terrain are cross-cut by newer patches of ice-rich, grooved bright terrain. Ganymede's diverse surface features bridge the stark divide ... read more
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.