From 1995 to 2003, NASA’s Galileo spacecraft checked out the Jupiter system. Its last orbits took the probe deep into the huge world’s innermost radiation belts, where it likewise carried out a close flyby ofAmalthea Credit: Michael Carroll
Researchers discover high-energy oxygen and sulfur ions in Jupiter‘s inner radiation belts– and a formerly unidentified ion source.
Nearly 20 years after completion of NASA‘s Galileo objective to Jupiter, researchers led by the Max Planck Institute for Solar System Research (MPS) in Germany have actually opened a brand-new trick from the objective’s comprehensive information sets. For the very first time, the research study group had the ability to figure out beyond doubt that the high-energy ions surrounding the gas giant as part of its inner radiation belt are mainly oxygen and sulfur ions. They are believed to have actually come from volcanic eruptions on Jupiter’s moonIo Near the orbit of the moon Amalthea, which orbits Jupiter more inward, the group found an all of a sudden high concentration of high-energy oxygen ions that can not be described by Io’s volcanic activity. A formerly unidentified ion source should be at work here. The outcomes of the research study were released today in the journal Science Advances
Planets like Earth, Jupiter, and Saturn with international electromagnetic fields of their own are surrounded by so-called radiation belts: Trapped in the electromagnetic field, quick moving charged particles such as electrons, protons, and much heavier ions whiz around hence forming the unnoticeable, torus-shaped radiation belts. With their high speeds reaching practically the speed of light, the particles can ionize other particles when they clash, producing a dangerous environment that can likewise threaten to area probes and their instruments. In this regard, the gas giant Jupiter sports the most severe radiation belts in the SolarSystem In their brand-new publication, scientists from the MPS, the California Institute of Technology (U.S.A.), the Johns Hopkins Applied Physics Laboratory (U.S.A.), the Laboratory of Instrumentation and Experimental Particle Physics (Portugal), and the Academy of Athens (Greece) now present the most extensive research study to date of the heavy ions in Jupiter’s inner radiation belts.
While the high-energy oxygen and sulfur ions outside Amalthea’s orbit are provided from the far-off magnetosphere as by-products of Io’s volcanic eruptions, another source needs to be accountable for the high concentration of high-energy oxygen ions inward of Amalthea, which avoids the transmission of such ions throughout its orbit. Credit: MPS
Like Jupiter’s huge electromagnetic field, its radiation belts extend numerous million kilometers into area; nevertheless, the area within the moon’s orbit of Europa, a location with a radius of about 670,000 kilometers around the gas giant, is the scene of the greatest energetic particle densities and speeds. Viewed from Jupiter, Europa is the second of the 4 big Jovian satellites called “Galilean moons” after their 17 th century originator. Io is the innermost Galilean moon. With the area probes Pioneer 11 in the mid-1970 s, Galileo from 1995 to 2003, and presently Juno, 3 area objectives have actually up until now ventured into this inner part of these radiation belts and carried out in-situ measurements. “Unfortunately, the data from Pioneer 11 and Juno do not allow us to conclude beyond doubt what kind of ions the spacecraft encountered there,” states MPS researcherDr Elias Roussos, lead author of the brand-new research study, explaining the present state of research study. “Therefore, their energies and origin were also unclear until now,” he includes. Only the now uncovered information from the last months of the Galileo objective is detailed enough to enhance this scenario.
Venturing into the inner radiation belts
NASA’s Galileo spacecraft reached the Jupiter system in1995 Equipped with the Heavy Ion Counter (HIC), contributed by the California Institute of Technology, and the Energetic Particle Detector (EPD), established and developed by Johns Hopkins Applied Physics Laboratory in cooperation with the MPS, the objective invested the following 8 years supplying basic insights into the circulation and characteristics of charged particles around the gas giant. However, to safeguard the spacecraft, it at first flew exclusively through the external, less severe areas of the radiation belts. Only in 2003, soon prior to completion of the objective, when a higher threat was reasonable, Galileo ventured into the inner area within the orbits of the moons Amalthea andThebe Viewed from Jupiter, Amalthea and Thebe are the 3rd and 4th moons of the huge world. The orbits of Io and Europa lie further external.
“Because of the exposure to strong radiation, it was to be expected that the measurement data from HIC and EPD from the inner region of the radiation belt would be heavily corrupted. After all, neither of these two instruments was specifically designed to operate in such a harsh environment”, Roussos explains his expectations when he began dealing with the present research study 3 years back. Nevertheless, the scientist wished to see for himself. As a member of NASA’s Cassini objective, he had actually seen Cassini’s last, likewise bold orbits at Saturn 2 years previously and evaluated the distinct information from that last objective stage. “The thought of the long-completed Galileo mission kept coming to my mind,” Roussos remembers. To his own surprise, amongst numerous unusable information sets there were likewise some that might be processed and evaluated with much effort.
Enigmatic oxygen ions
With the aid of this clinical treasure, the authors of the present research study have actually now had the ability to figure out for the very first time the ion structure within the inner radiation belts, in addition to the ions’ speeds and spatial circulation. In contrast to the radiation belts of Earth and Saturn, which are controlled by protons, the area within the orbit of Io likewise includes big quantities of the much heavier oxygen and sulfur ions, with oxygen ions dominating amongst the 2. “The energy distribution of the heavy ions outside the orbit of Amalthea suggests that they are largely introduced from a more distant region of the radiations belts,” Roussos states. The moon Io with its more than 400 active volcanoes, which consistently toss big quantities of sulfur and sulfur dioxide into area, and to a lower degree, Europa, are most likely the primary sources.
Further inward, within Amalthea’s orbit, the ion structure modifications significantly in favor of oxygen. “The concentration and the energy of oxygen ions there is much higher than expected,” Roussos states. Actually, the concentration ought to be reducing in this area, as the moons Amalthea and Thebe soak up inbound ions; the 2 little moons’ orbits hence form a sort of natural ion barrier. This habits is, for instance, understood from radiation belts of the Saturnian system with its numerous moons.
The just description for the increased concentration of oxygen ions is for that reason another, regional source in the inner area of the radiation belts. The release of oxygen following the crashes of sulfur ions with the great dust particles of Jupiter’s rings make up one possibility, as the scientists’ computer system simulations reveal. The rings, which are much fainter than the Saturnian ones, extend roughly as far as the orbit ofThebe However, it is likewise possible that low-frequency electro-magnetic waves in the magnetospheric environment of the innermost radiation belts heat oxygen ions to the observed energies.
“Currently, it is not possible to distinguish in favor of either of these possible sources,” Roussos states. Any of these 2 prospect systems, nonetheless, have parallels to high energy particle production in outstanding or extrasolar environments, even more developing that Jupiter’s radiation belts extend into the astrophysical world, a truth that the scientist hopes would validate their future expedition with a devoted area objective.
References:
“A source of very energetic oxygen located in Jupiter’s inner radiation belts” by Elias Roussos, Christina Cohen, Peter Kollmann, Marco Pinto, Norbert Krupp, Patricia Gon çalves and Konstantinos Dialynas, 12 January 2022, Science Advances
DOI: 10.1126/ sciadv.abm4234
“The in-situ exploration of Jupiter’s radiation belts” by Elias Roussos, Oliver Allanson, Nicolas Andr é, Bruna Bertucci, Graziella Branduardi-Raymont, George Clark, Konstantinos Dialynas, Iannis Dandouras, Ravindra T. Desai, Yoshifumi Futaana, Matina Gkioulidou, Geraint H. Jones, Peter Kollmann, Anna Kotova, Elena A. Kronberg, Norbert Krupp, Go Murakami, Quentin Nénon, Tom Nordheim, Benjamin Palmaerts, Christina Plainaki, Jonathan Rae, Daniel Santos-Costa, Theodore Sarris, Yuri Shprits, Ali Sulaiman, Emma Woodfield, Xin Wu and Zonghua Yao, 30 October 2021, Experimental Astronomy
DOI: 10.1007/ s10686-021-09801 -0
