Composition Of Outer Satellite Ices, What are Jupiter's moons made of? |
Composition Of Outer Satellite Ices, What are Jupiter's moons made of? |
Oct 31 2005, 03:41 PM
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
Paper: astro-ph/0510798
Date: Fri, 28 Oct 2005 10:23:28 GMT (316kb) Title: Modeling the Jovian subnebula: II - Composition of regular satellites ices Authors: Olivier Mousis and Yann Alibert Comments: 9 pages, A&A, in press \\ We use the evolutionary turbulent model of Jupiter's subnebula described by Alibert et al. (2005a) to constrain the composition of ices incorporated in its regular icy satellites. We consider CO2, CO, CH4, N2, NH3, H2S, Ar, Kr, and Xe as the major volatile species existing in the gas-phase of the solar nebula. All these volatile species, except CO2 which crystallized as a pure condensate, are assumed to be trapped by H2O to form hydrates or clathrate hydrates in the solar nebula. Once condensed, these ices were incorporated into the growing planetesimals produced in the feeding zone of proto-Jupiter. Some of these solids then flowed from the solar nebula to the subnebula, and may have been accreted by the forming Jovian regular satellites. We show that ices embedded in solids entering at early epochs into the Jovian subdisk were all vaporized. This leads us to consider two different scenarios of regular icy satellites formation in order to estimate the composition of the ices they contain. In the first scenario, icy satellites were accreted from planetesimals that have been produced in Jupiter's feeding zone without further vaporization, whereas, in the second scenario, icy satellites were accreted from planetesimals produced in the Jovian subnebula. In this latter case, we study the evolution of carbon and nitrogen gas-phase chemistries in the Jovian subnebula and we show that the conversions of N2 to NH3, of CO to CO2, and of CO to CH4 were all inhibited in the major part of the subdisk. Finally, we assess the mass abundances of the major volatile species with respect to H2O in the interiors of the Jovian regular icy satellites. Our results are then compatible with the detection of CO2 on the surfaces of Callisto and Ganymede and with the presence of NH3 envisaged in subsurface oceans within Ganymede and Callisto. \\ ( http://arXiv.org/abs/astro-ph/0510798 , 316kb) -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Dec 15 2005, 04:30 PM
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#2
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
Astrophysics, abstract
astro-ph/0504649 From: Paul Estrada [view email] Date (v1): Thu, 28 Apr 2005 20:20:34 GMT (67kb) Date (revised v2): Tue, 10 May 2005 23:19:41 GMT (68kb) Date (revised v3): Tue, 13 Dec 2005 21:42:03 GMT (107kb) A Gas-poor Planetesimal Capture Model for the Formation of Giant Planet Satellite Systems Authors: P. R. Estrada, I. Mosqueira Comments: 45 pages, 11 figures, 3 appendices, uses rgfmacro.tex, accepted for publication to Icarus Assuming that an unknown mechanism (e.g., gas turbulence) removes most of the subnebula gas disk in a timescale shorter than that for satellite formation, we develop a model for the formation of regular (and possibly at least some of the irregular) satellites around giant planets in a gas-poor environment. In this model, which follows along the lines of the work of Safronov et al. (1986), heliocentric planetesimals collide within the planet's Hill sphere and generate a circumplanetary disk of prograde and retrograde satellitesimals extending as far out as $\sim R_H/2$. At first, the net angular momentum of this proto-satellite swarm is small, and collisions among satellitesimals leads to loss of mass from the outer disk, and delivers mass to the inner disk (where regular satellites form) in a timescale $\lesssim 10^5$ years. This mass loss may be offset by continued collisional capture of sufficiently small $< 1$ km interlopers resulting from the disruption of planetesimals in the feeding zone of the giant planet. As the planet's feeding zone is cleared in a timescale $\lesssim 10^5$ years, enough angular momentum may be delivered to the proto-satellite swarm to account for the angular momentum of the regular satellites of Jupiter and Saturn.(abridged) http://arxiv.org/abs/astro-ph/0504649 -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Feb 3 2006, 04:08 PM
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#3
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
Paper: astro-ph/0602033
Date: Thu, 2 Feb 2006 02:50:36 GMT (387kb) Title: A low density of 0.8 g/cc for the Trojan binary asteroid 617 Patroclus Authors: Franck Marchis, Daniel Hestroffer, Pascal Descamps, Jerome Berthier, Antonin H. Bouchez, Randall D. Campbell, Jason C. Y. Chin, Marcos A. van Dam, Scott K. Hartman, Erik M. Johansson, Robert E. Lafon, David Le Mignant, Imke de Pater, Paul J. Stomski, Doug M. Summers, Frederic Vachier, Peter L. Wizinovich, Michael H. Wong Comments: 10 pages, 3 figures, 1 table Journal-ref: Nature, 439, 565-567, 2006 \\ The Trojan population consists of two swarms of asteroids following the same orbit as Jupiter and located at the L4 and L5 Lagrange points of the Jupiter-Sun system (leading and following Jupiter by 60 degrees). The asteroid 617 Patroclus is the only known binary Trojan (Merline et al. 2001). The orbit of this double system was hitherto unknown. Here we report that the components, separated by 680 km, move around the system centre of mass, describing roughly a circular orbit. Using the orbital parameters, combined with thermal measurements to estimate the size of the components, we derive a very low density of 0.8 g/cc. The components of Patroclus are therefore very porous or composed mostly of water ice, suggesting that they could have been formed in the outer part of the solar system. \\ ( http://arXiv.org/abs/astro-ph/0602033 , 387kb) -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Feb 5 2006, 12:10 AM
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#4
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Merciless Robot Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
QUOTE (ljk4-1 @ Feb 3 2006, 09:08 AM) Paper: astro-ph/0602033 Date: Thu, 2 Feb 2006 02:50:36 GMT (387kb) Title: A low density of 0.8 g/cc for the Trojan binary asteroid 617 Patroclus Authors: Franck Marchis, Daniel Hestroffer, Pascal Descamps, Jerome Berthier, Antonin H. Bouchez, Randall D. Campbell, Jason C. Y. Chin, Marcos A. van Dam, Scott K. Hartman, Erik M. Johansson, Robert E. Lafon, David Le Mignant, Imke de Pater, Paul J. Stomski, Doug M. Summers, Frederic Vachier, Peter L. Wizinovich, Michael H. Wong Comments: 10 pages, 3 figures, 1 table Journal-ref: Nature, 439, 565-567, 2006 \\ The Trojan population consists of two swarms of asteroids following the same orbit as Jupiter and located at the L4 and L5 Lagrange points of the Jupiter-Sun system (leading and following Jupiter by 60 degrees). The asteroid 617 Patroclus is the only known binary Trojan (Merline et al. 2001). The orbit of this double system was hitherto unknown. Here we report that the components, separated by 680 km, move around the system centre of mass, describing roughly a circular orbit. Using the orbital parameters, combined with thermal measurements to estimate the size of the components, we derive a very low density of 0.8 g/cc. The components of Patroclus are therefore very porous or composed mostly of water ice, suggesting that they could have been formed in the outer part of the solar system. \\ ( http://arXiv.org/abs/astro-ph/0602033 , 387kb) Should this be moved to the KBO thread, then? Suddenly, the Jovian Trojans are begging for a mission...Dawn 2, anyone? From a manned SF perspective, this could be quite significant as well in the distant future. The Jovian Trojans may have the most economically accessible supply of volatiles in the whole Solar System! -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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