Compound clathrate hydrate on Titan's surface

Osegovic, John P.; Max, M. D.

doi:10.1029/2005je002435

Cited by 59 publications

(56 citation statements)

References 12 publications

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“…Fortes and Stofan 2005;Osegovic and Max 2005;. Furthermore, if Titan had formed at such high temperatures, the D/H in water ice of Titan would be lower than that of OCCs (Owen 2008), which disagrees with the D/H measurement at Enceladus (Mousis et al 2009a).…”

Section: Titancontrasting

confidence: 42%

Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites

et al. 2015

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Comets play a dual role in understanding the formation and evolution of the solar system. First, the composition of comets provides information about the origin of the giant planets and their moons because comets formed early and their composition is not expected to have evolved significantly since formation. They, therefore serve as a record of conditions during the early stages of solar system formation. Once comets had formed, their orbits were perturbed allowing them to travel into the inner solar system and impact the planets. In this way they contributed to the volatile inventory of planetary atmospheres. We review here how knowledge of comet composition up to the time of the Rosetta mission has contributed to understanding the formation processes of the giant planets, their moons and small icy bodies in the solar system. We also discuss how comets contributed to the volatile inventories of the giant and terrestrial planets.

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Section: Titancontrasting

confidence: 42%

Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites

et al. 2015

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“…In situ clathrate hydrate formations (not involving ammonia) have been considered important in determining the surface composition and structures of this moon (40)(41)(42) and the presence of ammonia may play a role in these processes.…”

Section: Discussionmentioning

confidence: 99%

Ammonia clathrate hydrates as new solid phases for Titan, Enceladus, and other planetary systems

Shin

Kumar

Udachin

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

129

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There is interest in the role of ammonia on Saturn's moons Titan and Enceladus as the presence of water, methane, and ammonia under temperature and pressure conditions of the surface and interior make these moons rich environments for the study of phases formed by these materials. Ammonia is known to form solid hemi-, mono-, and dihydrate crystal phases under conditions consistent with the surface of Titan and Enceladus, but has also been assigned a role as water-ice antifreeze and methane hydrate inhibitor which is thought to contribute to the outgassing of methane clathrate hydrates into these moons' atmospheres. Here we show, through direct synthesis from solution and vapor deposition experiments under conditions consistent with extraterrestrial planetary atmospheres, that ammonia forms clathrate hydrates and participates synergistically in clathrate hydrate formation in the presence of methane gas at low temperatures. The binary structure II tetrahydrofuran + ammonia, structure I ammonia, and binary structure I ammonia + methane clathrate hydrate phases synthesized have been characterized by X-ray diffraction, molecular dynamics simulation, and Raman spectroscopy methods.ice | single crystal X-ray diffraction | hydrogen bonding | hydrate inhibitors | ethane A mmonia has long been seen as a key species in extraterrestrial space, both interstellar and on outer planets, moons, and comets and the interplay of ammonia, methane, and water has been the subject of a considerable number of studies and speculation (1-8). The main role assigned to ammonia has been that of an antifreeze for ice and clathrate hydrate formation, modifying the stability region of the solid ice and methane clathrate hydrate phases as a thermodynamic inhibitor (2, 5, 9). However, ammonia is a methane-sized molecule, thus based on size alone it has the potential for being a suitable guest for clathrate hydrate cages. Issues that may have prevented ammonia from being considered as a suitable clathrate guest molecule include the notion that guest species need to be hydrophobic in order to be incorporated into clathrates, and the observation of a number of stoichiometric nonclathrate phases of ammonia and water obtained upon cooling aqueous ammonia solutions (2). Previous experimental work on the water-ammonia and water-methaneammonia systems had not shown evidence for the enclathration of ammonia (5,(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). Close inspection, however, shows that the low pressure ammonia dihydrate (18) and the high pressure phase II of ammonia monohydrate (19) have structural features in common with canonical clathrate and semiclathrate structures.Recent structural analysis and molecular simulations have shown that some guest molecules which form strong hydrogen bonds with the water framework of the clathrate hydrate lattice may nonetheless produce stable phases (20-23). It is therefore reasonable to consider that ammonia has potential as a clathrate guest molecule. Furthermore, previous experimental and computational studies hav...

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“…Thomas et al (2007) have proposed the formation of clathrate hydrates on Titan's surface as a sink for krypton and xenon, while Osegovic & Max (2005) have calculated that compound clathrates could explain the absence of xenon and presumably krypton as well. The arguments presented above show that the special conditions required for clathrate formation are not required to explain the T. Owen and H. B. Niemann upper limits on these two gases given the detection threshold of the GCMS.…”

Section: (D ) Noble Gasesmentioning

confidence: 99%

The origin of Titan's atmosphere: some recent advances

Owen

Niemann

2008

Phil. Trans. R. Soc. A.

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It is possible to make a consistent story for the origin of Titan's atmosphere starting with the birth of Titan in the Saturn subnebula. If we use comet nuclei as a model, Titan's nitrogen and methane could have easily been delivered by the ice that makes up approximately 50 per cent of its mass. If Titan's atmospheric hydrogen is derived from that ice, it is possible that Titan and comet nuclei are in fact made of the same protosolar ice. The noble gas abundances are consistent with relative abundances found in the atmospheres of Mars and Earth, the Sun, and the meteorites.

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Compound clathrate hydrate on Titan's surface

Cited by 59 publications

References 12 publications

Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites

Constraints from Comets on the Formation and Volatile Acquisition of the Planets and Satellites

Ammonia clathrate hydrates as new solid phases for Titan, Enceladus, and other planetary systems

The origin of Titan's atmosphere: some recent advances

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