Thermal and non-thermal components of the X-ray emission from Jupiter

Abstract

Recent XMM-Newton and Chandra observations have revealed that Jupiter's X-ray emission comprises both, thermal and non-thermal spectral components. While the emission from the low-latitude planetary disk has the properties of scattered solar X-rays, with a thermal spectrum and typical coronal emission lines, the auroral soft (< 2 keV) X-rays are thought to be produced by ion charge exchange; very recently, a higher energy auroral component has been revealed by XMM-Newton: this is attributed to energetic electron bremsstrahlung, is dominant above 2 keV, and is variable, displaying both thermal and non-thermal characteristics. The disk and soft X-ray auroral components are separated spectroscopically in the high resolution data provided by the XMM-Newton Reflection Grating Spectrometer. Our results on the morphology, dynamics and energetics of the aurorae support current models developed to explain Jup iter's complex magnetosphere.