Japanese researchers have revealed that Saturn’s F ring and its shepherd satellites are natural outcome of the final stage of formation of Saturn’s satellite system.
According to the latest satellite formation theory, Saturn used to have ancient rings containing many more particles than they do today, and satellites formed from spreading and accretion of these particles. During the final stage of satellite formation, multiple small satellites tend to form near the outer edge of the ring.
In their simulations using in part computer systems at the National Astronomical Observatory of Japan, professor Ohtsuki Keiji and student Hyodo Ryuki from Kobe University revealed that the F ring and its shepherd satellites formed as these small satellites with a dense core collided and partially disintegrated. In other words, the system of the F ring and its shepherd satellites is a natural outcome of the formation process of Saturn’s ring-satellite system.
“As plans are underway in and outside of Japan to explore the satellite system of Jupiter and the satellites of Mars, we will continue to unravel the origin of satellite systems, which is key to understanding the formation process of planetary systems,” Ohtsuki said. The F ring is very narrow with a width of only a few hundred km and has two shepherd satellites called Prometheus and Pandora, which orbit inside and outside the ring, respectively.
Although the Voyager and Cassini spacecraft later made detailed observations of the F ring and its shepherd satellites, their origin has not been clarified till now. Saturn, which is the second largest planet in our solar system, is known to have multiple rings and satellites. This new finding is expected to help elucidate the formation of satellite systems both within and outside our solar system.
The paper was published online in the journal Nature Geoscience.