During the last days of the legendary Cassini mission, the NASA spacecraft performed a series of orbiting circuits around Saturn and snatched unprecedented images of the gas giant's enigmatic ring moons. These photos and other data have now been analyzed by astronomers, depicting new light on these ambiguities and the origins of Saturn's majestic rings.
Saturn has about 60 known moons, where a small handful is parked inside or closely interacting with the planet's ring system. New research published today in Science releases new knowledge on five of these ring month-Pan, Daphnis, Atlas, Pandora and Epimetheus ̵
Cassini's six ring grazing pathways took place between December 2016 and April 2017, when the mission ended in September 2017, when the probe deliberately struck down in Saturn. The pictures taken by Cassini were amazing and showed moons as opposed to anything that had ever been seen.
Take Pan, for example a femmile wide (8 km) moon with distinctive grooves on its surface and a rolling equatorial frame reminiscent of a tutu. Daphnis sits in an uncertain circuit in a hole in Saturn's ring, and it also has a "skirt" around its equator.
In fact, these are five inner moons, none of which are wider than approx. 12 km (20 km). They are quite distinctive and have unconventional shapes, surface properties and colors. Moreover, they seem to have a close but poorly understood relationship with Saturn's rings. Equipped with the new Cassini data and these unprecedented close-ups, Buratti and her colleagues could take a deeper look at these mysterious objects.
"We tried to understand how the ring moons and the head ring are related," Buratti said to Gizmodo. "Mostly they are the same?"
Buratti and her colleagues also looked for clues to find out if Saturn's rings formed in the wake of a celestial collision, and if the abundance of material in the rings gave birth to the ring-moons. In fact, the disk of stone and ice around Saturn may be analogous and involve similar processes, to the Sun's protoplanetary disk (from which the planets, including Earth, formed) in the early days of the Solar System. Finally, the researchers hoped to see if there were volatile chemicals other than water ice on these ring moons.
According to the analysis, the distinctive geology of these five months was due to a complex multi-strand process in which the objects are formed by conical ring material. Strong tidal pressure and the slow accumulation of ring particles caused the grooves and heights to form on the surface. It thus appears that the moons and the ring system are formed by a huge impact.
"The moons are gigantic swathes back from the impact," Buratti said to Gizmodo. The "skirts" around their equators are particles from the rings that continue to appear. The way the moons play particles in their path could be a minor example of how planets form from smaller particles. "
With regard to the nice colors, Pan is the redest, while Epimetheus is the bluest. Buratti said she was "totally surprised at how red in color Pan was" noting that the moons " Being rescued when coming close to Saturn, further suggesting that their surfaces have accumulated ring particles. "The chemicals responsible for the colors and processes involved are not yet fully understood, but it may involve red chromophores. a mixture of organic and iron, ice particles or water vapor from Saturn's E-ring and water vapor from volcanic plum on Saturn's moon Enceladus could be contributing factors, according to the paper.
"The study confirms the effect of the isis particles being launched from plum of Enceladus ha It's across the Saturn system, "said Tracy Becker, a planetary scientist at the southwestern research institute who was not involved in the new study, Gizmodo said. "It's fascinating to see how these tiny particles really change the moon's color and agility closest to Enceladus, and also exciting to see how well Saturn's rings protect the embedded satellites from some of these particles."
As far as volatile others than water ice were concerned, it was not found to exist on the surface of the ring moon.
"The presence of molecules with higher volatility than water ice would indicate material originating from a colder area outside the saturn system," the authors wrote in a new study. "For example, the discovery of CO2 ice on the irregular outer moon suggested Phoebe that it originates from the Kuiper Belt."
Therefore, the lack of volatiles is yet another proof that the ring-moons formed within the rings and became Saturn's intense gravity.
"The results of this paper help us better understand the complex cosmic interaction at work in the Saturnian system," Tanya says. Harrison, an astronomer at Arizona State University who is not affiliated with new study, told Gizmodo. "The moons, the ring particles, and even Saturn itself, are all interactive to create worlds and environments as opposed to elsewhere in our solar system."
The coolest part of the study, Harrison said, is that the strange ravioli-shaped moons -Pan, Daphnis and Atlas acquired their appearance by collecting ice and dust particles from Saturn's rings around their equators as they moved in their Fields. As for her favorite ring moon, this distinction goes to Pan.
"I want to know how it seems to stand at the bottom of his ring" belt "and look up at it," she said, "it looks pretty steep so I imagine it is a bit like The Wall in Game of Thrones . "
Like Harrison, Becker is also fascinated by Pan, especially the variations observed along its equatorial ridge. She wants to know why the thickness and extent of the back is so variable around the surface. Becker said that future studies should look at this and find out how and where the ring particles are assembled on the moon's surface.
Another interesting (but not completely surprising) observation, said Harrison, is that the closer a moon is to Enceladus, the bluer it is probably the result of all water ice and steam spears from Enceladus' south polar geysers.
"These things make up the whole of Saturn's E-ring and" snow "down on nearby moons, Harrison told Gizmodo." Enceladus makes a big but beautiful mess on the Saturnian system. "
The new paper is also important , Becker said in how Saturn's rings can be used as proxy for young stars discs where planets are formed the beginning of our own solar system.
"Having pictures and measurements of the satellites embedded in the rings is one of the best ways you can imagine how planets form, grow and interact with the disk, "Becker said.
Saturn is one of the most fascinating and exciting objects in the entire solar system, containing worlds of worlds and thanks to the late big Cassini we are fortunate enough to witness these alien places.