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Dependence of X-ray emission from Europa on solar activity cycle

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Title Dependence of X-ray emission from Europa on solar activity cycle
 
Creator K B, Smart
Babu, C A
 
Subject Solar corona
Europa
Tenuous
Exosphere
X-ray fluorescence
Rayleigh scattering
 
Description 16-22
The atmosphere of the Jovian Europa being tenuous, the interaction of the energetic solar photons is a probable source of
excitation for the emission of X-rays from the surface of the satellite. Solar photons in the X-region of the electromagnetic
spectrum have energies greater than the binding energy of the elemental constituents of the surface, cause excitation of
electrons, and on de-excitation cause emission of X-rays through X-ray fluorescence. We developed models for the
computation of the solar X-ray flux during the representative phases of a solar activity cycle (1-100 Å), and using these
fluxes, we computed the photon-induced X-ray fluorescent and Rayleigh scattering emission flux from the regolith of the
Europa by taking into account its predominant H2O ice composition. This work observed that during the extreme case of the
quiet Sun condition and an X2-class flare, the X-ray energy flux at the Europa distance of 4.96 AU vary from 1.08 × 10-7 to
5.23 × 10-4 ergs-cm-2s-1. This flux from the H2O ice composition can generate a total X-ray energy flux, inclusive of the
X-ray fluorescent and Rayleigh scattering events, varying as 1.40 × 10-23 to 6.21 × 10-20 ergs-cm-2s-1. These computed
numbers of the X-ray energy fluxes at the telescope of the Chandra X-ray Observatory are of lesser magnitude in
comparison to its observed numbers (3.0 × 10-16). This deduction reveals the influence of a stronger excitation source than
the photon-induced mechanisms of the generation of X-rays from the surface of the Europa.
 
Date 2022-01-21T11:34:31Z
2022-01-21T11:34:31Z
2022-01
 
Type Article
 
Identifier 0975-0959 (Online); 0301-1208 (Print)
http://nopr.niscair.res.in/handle/123456789/58943
 
Language en
 
Publisher NIScPR-CSIR, India
 
Source IJPAP Vol.60(01) [January 2022]