Secular and local time dependence of Jovian X ray emissions

Gladstone, G. Randall; Waite, J. H.; Lewis, William S.

doi:10.1029/98je00737

Cited by 40 publications

(42 citation statements)

References 8 publications

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“…We note that the model produces the largest x-ray brightnesses at the sub-solar point with values as high as 0.03 R. A solar source might thus explain the correlation of peak x-ray emission with the bright visible limb [Gladstone et al, 1998] and with modeled solar activity (figure 4). However, the model predicts non-auroral luminosities of at most 3 x 107 W which are approximately an order of magnitude less than the power output derived from the observations.…”

Section: Discussionmentioning

confidence: 99%

Jovian X‐ray emission from solar X‐ray scattering

Maurellis

Cravens

Gladstone

et al. 2000

Geophysical Research Letters

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Section: Discussionmentioning

confidence: 99%

Jovian X‐ray emission from solar X‐ray scattering

Maurellis

Cravens

Gladstone

et al. 2000

Geophysical Research Letters

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“…Since the first detection of X rays from Jupiter by the Einstein observatory in the 1980s [ Metzger et al , 1983], debate has persisted regarding the mechanism by which this emission arises. Owing to the limited spatial and spectral resolution of the first generation of X‐ray satellites, observations in the X‐ray band of 0.1–1 keV [ Waite et al , 1994; Gladstone et al , 1998] were insufficient to distinguish between the models seeking to explain them (cf. Bhardwaj and Gladstone [2000] for discussion).…”

Section: Introductionmentioning

confidence: 99%

Comparative analysis and variability of the Jovian X‐ray spectra detected by the Chandra and XMM‐Newton observatories

et al. 2010

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[1] Expanding upon recent work, a more comprehensive spectral model based on charge exchange induced X-ray emission by ions precipitating into the Jovian atmosphere is used to provide new understanding of the polar auroras. In conjunction with the Xspec spectral fitting software, the model is applied to analyze observations from both Chandra and XMM-Newton by systematically varying the initial precipitating ion parameters to obtain the best fit model for the observed spectra. In addition to the oxygen and sulfur ions considered previously, carbon is included to discriminate between solar wind and Jovian magnetospheric ion origins, enabled by the use of extensive databases of both atomic collision cross sections and radiative transitions. On the basis of fits to all the Chandra observations, we find that carbon contributes negligibly to the observed polar X-ray emission suggesting that the highly accelerated precipitating ions are of magnetospheric origin. Most of the XMM-Newton fits also favor this conclusion with one exception that implies a possible carbon contribution. Comparison among all the spectra from these two observatories in light of the inferred initial energies and relative abundances of precipitating ions from the modeling show that they are significantly variable in time (observation date) and space (north and south polar X-ray auroras).

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“…X‐ray emission from Jupiter was first unambiguously observed nearly 2 1/2 decades ago by the Earth‐orbiting Einstein observatory [ Metzger et al , 1983] (see Bhardwaj and Gladstone [2000] for a review of earlier searches for X‐ray emission from Jupiter). These initial observations were followed about a decade later by a series of ROSAT observations spanning a period of about 6 years [ Waite et al , 1994, 1995, 1997; Gladstone et al , 1998]. More recently, both X‐ray cameras on the Chandra X‐ray Observatory (CXO), the spectroscopy array of the Advanced CCD Imaging Spectrometer (ACIS‐S) and the imaging array of the High‐Resolution Camera (HRC‐I), have observed Jupiter [ Gladstone et al , 2002; Elsner et al , 2002, 2005a, 2005b, 2005c], as has the XMM‐Newton X‐ray Observatory [ Branduardi‐Raymont et al , 2004, 2006a, 2006b; Bhardwaj et al , 2005a].…”

Section: Introductionmentioning

confidence: 99%

Low‐ to middle‐latitude X‐ray emission from Jupiter

et al. 2006

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[1] The Chandra X-ray Observatory (CXO) observed Jupiter during the period 24-26 February 2003 for $40 hours (4 Jupiter rotations), using both the spectroscopy array of the Advanced CCD Imaging Spectrometer (ACIS-S) and the imaging array of the High-Resolution Camera (HRC-I). Two ACIS-S exposures, each $8.5 hours long, were separated by an HRC-I exposure of $20 hours. The low-to middle-latitude nonauroral disk X-ray emission is much more spatially uniform than the auroral emission. However, the low-to middle-latitude X-ray count rate shows a small but statistically significant hour angle dependence and depends on surface magnetic field strength. In addition, the X-ray spectra from regions corresponding to 3-5 gauss and 5-7 gauss surface fields show significant differences in the energy band 1.26-1.38 keV, perhaps partly due to line emission occurring in the 3-5 gauss region but not the 5-7 gauss region. A similar correlation of surface magnetic field strength with count rate is found for the 18 December 2000 HRC-I data, at a time when solar activity was high. The low-to middle-latitude disk X-ray count rate observed by the HRC-I in the February 2003 observation is about 50% of that observed in December 2000, roughly consistent with a decrease in the solar activity index (F10.7 cm flux) by a similar amount over the same time period. The low-to middle-latitude X-ray emission does not show any oscillations similar to the $45 min oscillations sometimes seen from the northern auroral zone. The temporal variation in Jupiter's nonauroral X-ray emission exhibits similarities to variations in solar X-ray flux observed by GOES and TIMED/SEE. The two ACIS-S 0.3-2.0 keV low-to middle-latitude X-ray spectra are harder than the auroral spectrum and are different from each other at energies above 0.7 keV, showing variability in Jupiter's nonauroral X-ray emission on a timescale of a day. The 0.3-2.0 keV X-ray power emitted at low to middle latitudes is 0.21 GW and 0.39 GW for the first and second ACIS-S exposures, respectively. We suggest that X-ray emission from Jupiter's disk may be largely generated by the scattering and fluorescence of solar X rays in its upper atmosphere, especially at times of high incident solar X-ray flux. However, the dependence of count rate on surface magnetic-field strength may indicate the presence of some secondary component, possibly ion precipitation from radiation belts close to the planet.

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Secular and local time dependence of Jovian X ray emissions

Cited by 40 publications

References 8 publications

Jovian X‐ray emission from solar X‐ray scattering

Jovian X‐ray emission from solar X‐ray scattering

Comparative analysis and variability of the Jovian X‐ray spectra detected by the Chandra and XMM‐Newton observatories

Low‐ to middle‐latitude X‐ray emission from Jupiter

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