Categories: SaturnSolar Astronomy

Temporary Radiation Belt Discovered at Saturn

[/caption]
A new, temporary radiation belt has been detected at Saturn, located about 377,000 km from the center of the planet, near the orbit of the moon Dione. The temporary radiation belt was short-lived and formed three times in 2005. It was observed as sudden increases in the intensity of high energy charged particles in the inner part of Saturn’s magnetosphere, in the vicinity of the moons Dione and Tethys, and likely was caused by a change in the intensities of cosmic rays at Saturn.

“These intensifications, which could create temporary satellite atmospheres around these moons,” said Dr. Elias Roussos, “occurred three times in 2005 as a response to an equal number of solar storms that hit Saturn’s magnetosphere and formed a new, temporary component to Saturn’s radiation belts.”

The discovery was made possible by Cassini’s five-plus year mission, allowing scientists to observe and assess changes in Saturn’s radiation belts. An international team of astronomers made the discovery analyzing data from the Magnetospheric Imaging instrument (MIMI) on Cassini MIMI’s LEMMS sensor, which measures the energy and angular distribution of charged particles in the magnetic bubble that surrounds Saturn.

Saturn's moon Dione. Credit: NASA

The new belt, which has been named “the Dione belt”, was only detected by MIMI/LEMMS for a few weeks after each of its three appearances. The team believe that newly formed charged particles in the Dione belt were gradually absorbed by Dione itself and another nearby moon, named Tethys, which lies slightly closer to Saturn at an orbit of 295 000km.

Unlike the Van Allen belts around the Earth, Saturn’s radiation belts inside the orbit of Tethys are very stable, showing negligible response to solar storm occurrences and no variability over the five years that they have been monitored by Cassini.

Interestingly, it was found that the transient Dione belt was only detected outside the orbit of Tethys. It appeared to be clearly separated from the inner belts by a permanent radiation gap all along the orbit of Tethys.

“Our observations suggest that Tethys acts as a barrier against inward transport of energetic particles and is shielding the planet’s inner radiation belts from solar wind influences. That makes the inner, ionic radiation belts of Saturn the most isolated magnetospheric structure in our solar system“, said Dr Roussos.

The radiation belts within Tethys’s orbit probably arise from the interaction of the planet’s main rings and atmosphere and galactic cosmic ray particles that, unlike the solar wind, have the very high energies needed to penetrate the innermost Saturnian magnetosphere. This means that the inner radiation belts will only vary if the cosmic ray intensities at the distance of Saturn change significantly.

However, Roussos emphasized that outside the orbit of Tethys, the variability of Saturn’s radiation belt might be enhanced in the coming years as solar maximum approaches. “If solar storms occur frequently in the new solar cycle, the Dione belt might become a permanent, although highly variable, component of Saturn’s magnetosphere, which could affect significantly Saturn’s global magnetospheric dynamics,” he said.

The new findings were presented at the European Planetary Science Congress in Potsdam, Germany.

Nancy Atkinson

Nancy has been with Universe Today since 2004, and has published over 6,000 articles on space exploration, astronomy, science and technology. She is the author of two books: "Eight Years to the Moon: the History of the Apollo Missions," (2019) which shares the stories of 60 engineers and scientists who worked behind the scenes to make landing on the Moon possible; and "Incredible Stories from Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos" (2016) tells the stories of those who work on NASA's robotic missions to explore the Solar System and beyond. Follow Nancy on Twitter at https://twitter.com/Nancy_A and and Instagram at and https://www.instagram.com/nancyatkinson_ut/

Recent Posts

New View of Venus Reveals Previously Hidden Impact Craters

Think of the Moon and most people will imagine a barren world pockmarked with craters.…

27 mins ago

Multimode Propulsion Could Revolutionize How We Launch Things to Space

In a few years, as part of the Artemis Program, NASA will send the "first…

11 hours ago

China Trains Next Batch of Taikonauts

China has a fabulously rich history when it comes to space travel and was among…

12 hours ago

NASA Focusses in on Artemis III Landing Sites.

It was 1969 that humans first set foot on the Moon. Back then, the Apollo…

13 hours ago

The Connection Between Black Holes and Dark Energy is Getting Stronger

The discovery of the accelerated expansion of the Universe has often been attributed to the…

15 hours ago

Will Advanced Civilizations Build Habitable Planets or Dyson Spheres

Freeman Dyson proposed that advanced civilizations might eventually harvest all the energy coming from their…

18 hours ago