Scientists compile Cassini’s unique observations of Saturn’s rings

Southwest Analysis Institute scientists have compiled 41 solar occultation observations of Saturn’s rings from the Cassini mission. The compilation, revealed lately within the journal Icarus, will inform future investigations of the particle dimension distribution and composition of Saturn’s rings, key components to understanding their formation and evolution.

“For almost 20 years, NASA’s Cassini spacecraft shared the wonders of Saturn and its household of icy moons and signature rings, however we nonetheless do not definitively know the origins of the ring system,” mentioned Dr. Stephanie Jarmak, a researcher within the SwRI House Science Division. “Proof signifies that the rings are comparatively younger and will have shaped from the destruction of an icy satellite or a comet. Nevertheless, to assist anybody origin idea, we have to have a good suggestion of the dimensions of particles making up the rings.”

Cassini’s Ultraviolet Imaging Spectrograph (UVIS) was uniquely delicate to a few of the smallest ring particles, significantly with the observations it made within the excessive ultraviolet wavelength.

To find out the dimensions of the ring particles, UVIS noticed them when the instrument was pointed on the sun, wanting by way of the rings in what is called a solar occultation. Ring particles partially blocked the trail of the sunshine, offering a direct measurement of the optical depth, a key parameter for figuring out the dimensions and composition of the ring particles.

“Given the wavelength of the sunshine coming from the sun, these observations gave us perception into the smallest particle sizes with Saturn’s rings,” Jarmak mentioned. “UVIS can detect dust particles on the micron degree, serving to us perceive the origin, collisional exercise and destruction of the ring particles throughout the system.”

The compilation additionally delves into the variations within the optical depth of occultation observations, which can assist decide particle size and composition. Throughout an occultation, mild emitted by a background supply, such because the sun, is absorbed and scattered by the particles within the mild’s path. The quantity of sunshine blocked by ring particles offers a direct measurement of the ring optical depth.

Together with optical depth is important to understanding the construction of the rings. The analysis measured the optical depth as a operate of the viewing geometry, which refers back to the remark angles of the ring system with respect to the Cassini spacecraft. As mild passing by way of the rings modifications at numerous angles, scientists can kind an image of the rings’ buildings.

“Ring programs round giant planets additionally present take a look at beds for investigating basic bodily properties and processes in our solar system normally,” Jarmak mentioned. “These particles are thought to consequence from objects colliding and forming in a disk and increase bigger particles. Understanding how they kind these ring programs may assist us perceive how planets kind as nicely.”

The paper seems in Icarus.