资源环境科技发展态势分析平台

In April 2011 Saturn's midlatitude ionospheric H-3(+) emissions were detected, exhibiting anomalous (nonsolar) H-3(+) latitudinal variations consistent with the transport of water from specific locations in Saturn's rings, known as "ring rain". These products, transported to the planet along the magnetic field, may help to explain the unusual pattern of peaks and troughs in electron densities discovered in Saturn's ionosphere by spacecraft flybys. In the present study, we analyzed H-3(+) emissions recorded on 23 April 2013, showing for the first time since the original detection that Saturn's H-3(+) emissions are indeed heavily modified. Although the 2013 emissions are dimmer by almost a factor of 3.7, the latitudinal contrast is greater and uncertainties are lower. Increased H-3(+) intensities were found near planetocentric latitudes of 43 degrees, 51 degrees, and 63 degrees, previously identified with sources at the inner edge of the B ring, A ring, and the orbit of Enceladus and associated E ring.