Particles Co-orbital to Janus and to Epimetheus: A Firefly Planetary Ring

• Autor(a) principal: Winter, Othon C. [UNESP]
• Data de Publicação: 2018
• Outros Autores: Souza, Alexandre P. S. [UNESP], Sfair, Rafael [UNESP], Winter, Silvia M. Giuliatti [UNESP], Mourão, Daniela C. [UNESP], Foryta, Dietmar W.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.3847/1538-4357/aa9c7f; http://hdl.handle.net/11449/179499
• topic: planets and satellites: dynamical evolution and stability; planets and satellites: individual (Epimetheus, Janus); planets and satellites: rings

The Cassini spacecraft found a new and unique ring that shares the trajectory of Janus and Epimetheus, co-orbital satellites of Saturn. Performing image analysis, we found this to be a continuous ring. Its width is between 30% and 50% larger than previously announced. We also verified that the ring behaves like a firefly. It can only be seen from time to time, when Cassini, the ring, and the Sun are arranged in a particular geometric configuration, in very high phase angles. Otherwise, it remains in the dark, invisible to Cassini's cameras. Through numerical simulations, we found a very short lifetime for the ring particles, less than a couple of decades. Consequently, the ring needs to be constantly replenished. Using a model of particle production due to micrometeorites impacts on the surfaces of Janus and Epimetheus, we reproduce the ring, explaining its existence and the firefly behavior.