Cuzzi Jeffrey N, Marouf Essam A, French Richard G, Murray Carl D, Cooper Nicholas J
Ames Research Center, NASA, Moffett Field CA 94035, USA.
San Jose State University, San Jose, CA, USA.
Sci Adv. 2024 May 10;10(19):eadl6601. doi: 10.1126/sciadv.adl6601.
One of the stranger planetary rings is Saturn's narrow, clumpy F ring, lying just outside the main rings, in a region disturbed by chaotic orbital dynamics. We show that the F ring has a stable "true core" that dominates its mass and is confined into discontinuous short arcs of particles larger than a few millimeters in radius. The more obvious micron-size particles seen in images, outlining and obscuring the true core, contribute only a small fraction of its mass. We found that these arcs of large particles orbit Saturn in a specific corotational resonance with the nearby 100-kilometer diameter ringmoon Prometheus, which stabilizes the F ring material and allows it to persist within the disturbed region for decades or longer. Toward the end of the observing period, a small chaotic glitch in the orbit of Prometheus temporarily disrupted the confinement, but the arcs seem to be able to adapt.
较为奇特的行星环之一是土星狭窄且块状的F环，它位于主环之外，处于一个受混乱轨道动力学干扰的区域。我们发现F环有一个稳定的“真正核心”，该核心主导着其质量，并被限制在半径大于几毫米的粒子组成的不连续短弧内。图像中更明显的微米级粒子勾勒并掩盖了真正的核心，但其质量仅占一小部分。我们发现，这些大粒子弧与附近直径100公里的卫星土卫十六以特定的共转共振环绕土星运行，这使F环物质得以稳定，并使其在受干扰区域内持续存在数十年甚至更久。在观测期即将结束时，土卫十六轨道上的一个小的混沌波动暂时扰乱了这种限制，但这些弧似乎能够自行调整。
