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Fig. 4. Chandra X-ray image of Jupiter on December 18, 2000 generated from 10 h of
continuous observations. A jovicentric graticule with 30 intervals is overplotted, along
with the L =5 . 9and L = 30 footprints of the magnetic field model. The image shows
strong auroral X-ray emissions from high latitudes and rather uniform emissions from
the disk [see Ref. 25 for details].
significantly poleward ( > 30 R J ) of the latitudes connected to the inner mag-
netosphere (Figs. 4 and 8) and (2) the auroral hot spot X-rays pulsate with
periodicity that is regular (
45 min) at time 25 and chaotic at other times 26
(vary over the 20-70 min range, cf. Fig. 5). Chandra observations also found
(Fig. 5) that X-rays from the north and south auroral regions are neither
in phase nor in anti-phase, but that the peaks in the south are shifted from
those in the north by about 120 (i.e., one-third of a planetary rotation). 26
Periodic oscillations on time scale of 20-70 min are not observed in the
XMM-Newton data, 27 , 28 perhaps due to lower spatial resolution of XMM-
Newton relative to the Chandra.
The Chandra-ACIS 26 and XMM-Newton 27 - 29 observations have pro-
vided soft X-ray spectra from the Jovian aurora, which consist of line
emissions that are consistent with high-charge states of precipitating heavy
(C, O, S) ions, and not a continuum as might be expected from electron
bremsstrahlung (see Figs. 6 and 9(a,b)).
XMM-Newton has provided spectral information on the X-rays from
Jupiter, which is somewhat better than Chandra. The RGS on XMM-
Newton clearly resolves the strongest lines in the spectra, while the EPIC
camera has provided images of the planets in the strong OVII and OVIII
lines present in the Jovian auroral emissions. 28 , 29
The spectral interpretation of Chandra and XMM-Newton observations
is consistent with a source due to energetic ion precipitation that undergoes
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