The origin of Titan's atmosphere: some recent advances

Owen, Tobias; Niemann, H. B.

doi:10.1098/rsta.2008.0247

Cited by 26 publications

(17 citation statements)

References 34 publications

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“…The instrument simply did not have the sensitivity to detect Kr and Xe given the observed abundance of 36 Ar in any of these reservoirs. Although the processes proposed for the nondetection of krypton and xenon may be operating on Titan, the available data do not reveal or require them [ Owen and Niemann , 2009]. Of course, Titan might have collected its noble gases from a completely different mixture from those we know.…”

Section: Discussionmentioning

confidence: 99%

Composition of Titan's lower atmosphere and simple surface volatiles as measured by the Cassini‐Huygens probe gas chromatograph mass spectrometer experiment

et al. 2010

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The Cassini‐Huygens probe gas chromatograph mass spectrometer (GCMS) determined the composition of the Titan atmosphere from ∼140 km altitude to the surface. After landing, it returned composition data of gases evaporated from the surface. Height profiles of molecular nitrogen (N2), methane (CH4), and molecular hydrogen (H2) were determined. Traces were detected on the surface of evaporating methane, ethane (C2H6), acetylene (C2H2), cyanogen (C2N2), and carbon dioxide (CO2). The methane data showed evidence that methane precipitation occurred recently. The methane mole fraction was (1.48 ± 0.09) × 10−2 in the lower stratosphere (139.8–75.5 km) and (5.65 ± 0.18) × 10−2 near the surface (6.7 km to the surface). The molecular hydrogen mole fraction was (1.01 ± 0.16) × 10−3 in the atmosphere and (9.90 ± 0.17) × 10−4 on the surface. Isotope ratios were 167.7 ± 0.6 for 14N/15N in molecular nitrogen, 91.1 ± 1.4 for 12C/13C in methane, and (1.35 ± 0.30) × 10−4 for D/H in molecular hydrogen. The mole fractions of 36Ar and radiogenic 40Ar are (2.1 ± 0.8) × 10−7 and (3.39 ± 0.12) × 10−5, respectively. 22Ne has been tentatively identified at a mole fraction of (2.8 ± 2.1) × 10−7. Krypton and xenon were below the detection threshold of 1 × 10−8 mole fraction. Science data were not retrieved from the gas chromatograph subsystem as the abundance of the organic trace gases in the atmosphere and on the ground did not reach the detection threshold. Results previously published from the GCMS experiment are superseded by this publication.

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Section: Discussionmentioning

confidence: 99%

Composition of Titan's lower atmosphere and simple surface volatiles as measured by the Cassini‐Huygens probe gas chromatograph mass spectrometer experiment

et al. 2010

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“…The presence of radiogenic 40 Ar, outgassed from Titan's rocky interior, indicates that the interior and atmosphere are connected [ Niemann et al , ]. The nondetection of Kr and Xe is not particularly surprising; the upper limits are consistent with solar abundances and a number of other atmospheres in the solar system [ Owen and Niemann , ]. Additionally, there are a number of possible noble gas sequestration mechanisms, both prior to and after formation:

H_{3}^{+}

complexes [ Pauzat et al , ], trapping in hazes [ Jacovi and Bar‐Nun , ], dissolution in lakes and seas [ Cordier et al , ; Hodyss et al , ], and trapping in clathrate hydrates [ Mousis et al , ; Tobie et al , ].…”

Section: The Age and Origin Of Titan's Atmospherementioning

confidence: 99%

Titan's atmosphere and climate

2017

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Titan is the only moon with a substantial atmosphere, the only other thick N2 atmosphere besides Earth's, the site of extraordinarily complex atmospheric chemistry that far surpasses any other solar system atmosphere, and the only other solar system body with stable liquid currently on its surface. The connection between Titan's surface and atmosphere is also unique in our solar system; atmospheric chemistry produces materials that are deposited on the surface and subsequently altered by surface‐atmosphere interactions such as aeolian and fluvial processes resulting in the formation of extensive dune fields and expansive lakes and seas. Titan's atmosphere is favorable for organic haze formation, which combined with the presence of some oxygen‐bearing molecules indicates that Titan's atmosphere may produce molecules of prebiotic interest. The combination of organics and liquid, in the form of water in a subsurface ocean and methane/ethane in the surface lakes and seas, means that Titan may be the ideal place in the solar system to test ideas about habitability, prebiotic chemistry, and the ubiquity and diversity of life in the universe. The Cassini‐Huygens mission to the Saturn system has provided a wealth of new information allowing for study of Titan as a complex system. Here I review our current understanding of Titan's atmosphere and climate forged from the powerful combination of Earth‐based observations, remote sensing and in situ spacecraft measurements, laboratory experiments, and models. I conclude with some of our remaining unanswered questions as the incredible era of exploration with Cassini‐Huygens comes to an end.

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“…One possibility is that the icy planetesimals formed at temperatures >75 K so that the noble gases and CH 4 were not captured, but NH 3 and CO 2 were. However, Owen and Niemann (2009) showed that the detection of Ar but not Kr or Xe could instead be due to the limited sensitivity of the Huygens probe instrument given the relative abundance of these elements in other solar system bodies, making such arguments inconclusive.…”

Section: Saturn Systemmentioning

confidence: 94%