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Callisto's Atmosphe...
Callisto's Atmosphere : First Evidence for H-2 and Constraints on H2O
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- Mogan, Shane R. Carberry R. (författare)
- KTH,Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA.;NYU, New York, NY 10012 USA.;New York Univ Abu Dhabi, Abu Dhabi, U Arab Emirates.;Univ Bern, Bern, Switzerland.
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- Tucker, Orenthal J. J. (författare)
- NASA, Goddard Space Flight Ctr, Greenbelt, MD USA.
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- Johnson, Robert E. E. (författare)
- NYU, New York, NY 10012 USA.;Univ Virginia, Charlottesville, VA USA.
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- Roth, Lorenz (författare)
- KTH,Rymd- och plasmafysik
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- Alday, Juan (författare)
- Univ Oxford, Oxford, England.;Open Univ, Milton Keynes, England.
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- Vorburger, Audrey (författare)
- Univ Bern, Bern, Switzerland.
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- Wurz, Peter (författare)
- Univ Bern, Bern, Switzerland.
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- Galli, Andre (författare)
- Univ Bern, Bern, Switzerland.
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- Smith, H. Todd (författare)
- Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA.
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- Marchand, Benoit (författare)
- New York Univ Abu Dhabi, Abu Dhabi, U Arab Emirates.
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- Oza, Apurva V. V. (författare)
- Univ Bern, Bern, Switzerland.;CALTECH, Jet Prop Lab, Pasadena, CA USA.
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KTH Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA;NYU, New York, NY 10012 USA.;New York Univ Abu Dhabi, Abu Dhabi, U Arab Emirates.;Univ Bern, Bern, Switzerland. (creator_code:org_t)
- American Geophysical Union (AGU), 2022
- 2022
- Engelska.
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Ingår i: Journal of Geophysical Research - Planets. - : American Geophysical Union (AGU). - 2169-9097 .- 2169-9100. ; 127:11
- Relaterad länk:
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https://doi.org/10.1...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- We explore the parameter space for the contribution to Callisto's H corona observed by the Hubble Space Telescope from sublimated H2O and radiolytically produced H-2 using the Direct Simulation Monte Carlo method. The spatial morphology of this corona produced via photoelectron and magnetospheric electron-impact-induced dissociation is described by tracking the motion of and simulating collisions between the hot H atoms and thermal molecules including a near-surface O-2 component. Our results indicate that sublimated H2O produced from the surface ice, whether assumed to be intimately mixed with or distinctly segregated from the dark nonice or ice-poor regolith, cannot explain the observed structure of the H corona. On the other hand, a global H-2 component can reproduce the observation, and is also capable of producing the enhanced electron densities observed at high altitudes by Galileo's plasma-wave instrument, providing the first evidence of H-2 in Callisto's atmosphere. The range of H-2 surface densities explored, under a variety of conditions, that are consistent with these observations is similar to(0.4-1) x 10(8) cm(-3). The simulated H-2 escape rates and estimated lifetimes suggest that Callisto has a neutral H-2 torus. We also place a rough upper limit on the peak H2O number density (less than or similar to 10(8) cm(-3)), column density (less than or similar to 10(15) cm(-2)), and sublimation flux (less than or similar to 10(12) cm(-2) s(-1)), all of which are 1-2 orders of magnitude less than that assumed in previous models. Finally, we discuss the implications of these results, as well as how they compare to Europa and Ganymede.
Ämnesord
- NATURVETENSKAP -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)
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Mogan, Shane R. ...
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Tucker, Orenthal ...
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Johnson, Robert ...
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Roth, Lorenz
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Alday, Juan
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Vorburger, Audre ...
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visa fler...
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Wurz, Peter
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Galli, Andre
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Smith, H. Todd
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Marchand, Benoit
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Oza, Apurva V. V ...
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visa färre...
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