Geoscience Reference
In-Depth Information
Fig. 12.
XMM-Newton
EPIC spectrum of Jupiter's disk and
best fit, with solar
mekal
abundances (see text for details).
temperature) is also a good representation of the low-latitude disk spectrum
(Fig. 12), after including additional MgXI and SiXIII emission (at 1.35 and
1.86 keV, respectively, likely consequences of enhanced solar activity) and
a small contribution of OVII (0.57 keV) and OVIII (0.65 keV, both residual
auroral contamination). However, the auroral spectra are better fitted when
using elemental abundances appropriate to the solar wind,
15
while solar
values
16
apply to the equatorial spectrum.
The higher resolution RGS
17
spectrum, which includes X-ray light from
the whole planet, agrees well, in flux and profile, with the EPIC one inte-
grated over the full disk of Jupiter (Fig. 13). The RGS clearly resolves the
strongest emission lines. A simultaneous fit (combination of
mod-
els as for the auroral spectra) shows some discrepancies from the data: this
highlights the diculty of fitting disk and auroral spectra together (because
they are clearly different and the RGS cannot easily separate the two spa-
tially) as well as the fact that a thin plasma model is not an adequate
approximation of the charge exchange mechanism (especially when fitting
high resolution spectra). More appropriate model descriptions are being
investigated.
12
mekal
