  We present the first X-ray observation of Jupiter by XMM-Newton. Images taken
with the EPIC cameras show prominent emission, essentially all confined to the
0.2-2.0 keV band, from the planet's auroral spots; their spectra can be
modelled with a combination of unresolved emission lines of highly ionised
oxygen (OVII and OVIII), and a pseudo-continuum which may also be due to the
superposition of many weak lines. A 2.8 sigma enhancement in the RGS spectrum
at 21-22 A (~0.57 keV) is consistent with an OVII identification. Our spectral
analysis supports the hypothesis that Jupiter's auroral emissions originate
from the capture and acceleration of solar wind ions in the planet's
magnetosphere, followed by X-ray production by charge exchange. The X-ray flux
of the North spot is modulated at Jupiter's rotation period. We do not detect
evidence for the ~45 min X-ray oscillations observed by Chandra more than two
years earlier. Emission from the equatorial regions of the planet's disk is
also observed. Its spectrum is consistent with that of scattered solar X-rays.
