References of "Espinosa, S A"
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See detailChandra X-ray Observations of the Jovian System
Elsner, R. F.; Waite, J. H.; Crary, F. et al

Conference (2002)

High-spatial resolution Chandra x-ray obsrvations have demonstrated that most of Jupiter's northern auroral x-rays come from a hot spot located significantly poleward of the latitudes connected to the ... [more ▼]

High-spatial resolution Chandra x-ray obsrvations have demonstrated that most of Jupiter's northern auroral x-rays come from a hot spot located significantly poleward of the latitudes connected to the inner magnetosphere. This hot spot appears fixed in magnetic latitude and longitude and coincides with a region exhibiting anomalous ultraviolet and infrared emissions. The hot spot also exhibited approximately 45 minute quasi-periodic oscillations, a period similar to those reported for high-latitude radio and energetic electron bursts observed by near-Jupiter spacecraft. These results invalidate the idea that jovian auroral x-ray emissions are mainly excited by steady precipitation of energetic heavy ions from the inner magnetosphere. Instead, the x-rays appear to result from currently unexplained processes in the outer magnetosphere that produce highly localized and highly variable emissions over an extremely wide range of wavelengths. The Chandra observations also revealed for the first time x-ray emission (about 0.1 GW) from the Io Plasma Torus, as well as very faint x-ray emission (about 1-2 MW) from the Galilean moons Io, Europa, and possibly Ganymede. The emission from the moons is almost certainly due to Kalpha emission of surface atoms (and possibly impact atoms) excited by the impact of highly energetic protons, oxygen, and sulfur atoms and ions from the Torus. The Torus emission is less well understood at present, although bremsstrahlung from the non-thermal tail of the electron distribution may provide a significant fraction. In any case, further observations, already accepted and in the process of being planned, with Chandra, some with the moderate energy resolution of the CCD camera, together with simultaneous Hubble Space Telescope observations and hopefully ground-based IRTF observations should soon provide greater insight into these various processes. [less ▲]

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See detailSoft X-ray emissions from planets, moons, and comets
Bhardwaj, A.; Gladstone, G. R.; Elsner, R. F. et al

Conference (2002)

A wide variety of solar system bodies are now known to radiate in the soft X-ray energy (<5 keV) regime. These include planets (Earth, Jupiter, Venus, Saturn, Mars): bodies having thick atmospheres, with ... [more ▼]

A wide variety of solar system bodies are now known to radiate in the soft X-ray energy (<5 keV) regime. These include planets (Earth, Jupiter, Venus, Saturn, Mars): bodies having thick atmospheres, with or without intrinsic magnetic field; planetary satellites (Moon, Io, Europa, Ganymede): bodies with thin or no atmospheres; and comets and Io plasma torus: bodies having extended tenuous atmospheres. Several different mechanisms have been proposed to explain the generation of soft X-rays from these objects, whereas in the hard X-ray energy range (>10 keV) X-rays mainly result from the electron bremsstrahlung process. In this paper we present a brief review of the X-ray observations on each of the planetary bodies and discuss their characteristics and proposed source mechanisms. [less ▲]

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See detailObservations of the Jovian System with the Chandra X-ray Observatory
Elsner, R. F.; Gladstone, G. R.; Lewis, W. S. et al

Conference (2002)

Sensitive, very high spatial-resolution x-ray observations with the Chandra X-ray Observatory have revealed that Jupiter's northern x-ray aurora originates at a spot fixed in a coordinate system rotating ... [more ▼]

Sensitive, very high spatial-resolution x-ray observations with the Chandra X-ray Observatory have revealed that Jupiter's northern x-ray aurora originates at a spot fixed in a coordinate system rotating with the planet at latitude (60-70 deg north) and longitude (160-180 deg System III). The northern auroral x-ray emission varies with a period about 45 minute and has an average power of about 1 GW. Jupiter's disk also emits x-rays with a power of about 2 GW, perhaps resulting from reprocessing of solar x-rays in its atmosphere. These observations reveal for the first time x-ray emission from the Io Plasma Torus, with a power of about 0.1 GW. Finally, we report the discovery of very faint (about 1-2 MW) soft x-ray emission from the Galilean satellites Io, Europa, and probably Ganymede. [less ▲]

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