Production and Chemical Analysis of Cometary Ice Tholins

McDonald, G. D.; Whited, L.J.; DeRuiter, Cynthia; Khare, B. N.; Patnaik, Archita; Sagan, Carl

doi:10.1006/icar.1996.0112

Cited by 68 publications

(39 citation statements)

References 9 publications

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“…Alternatively, these molecules could be produced by UV irradiation of grain mantles: laboratory experiments have shown that ethylene glycol (but not ethanol) can be easily formed in such environment from water-methanol ice mixtures (McDonald et al 1996;Cottin et al 1999;Hudson & Moore 2000). Unlike in comet Hale-Bopp, glycolaldehyde and ethylene glycol are observed with similar abundances in Sgr B2(N) within a 1 region.…”

Section: Discussionmentioning

confidence: 99%

Ethylene glycol in comet C/1995 O1 (Hale-Bopp)

Crovisier

Bockelée‐Morvan

Biver

et al. 2004

A&A

121

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Section: Discussionmentioning

confidence: 99%

Ethylene glycol in comet C/1995 O1 (Hale-Bopp)

Crovisier

Bockelée‐Morvan

Biver

et al. 2004

A&A

121

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“…Notably, such spectra ( Fig. 3) were quite similar to those of major and minor HPLC fractions separated from ice tholins (McDonald et al 1996), thereby pointing out the dominance of hydroxylated compounds by photoirradiation. A very strong band at 3336 cm -1 supports the existence of O-H bonds associated by hydrogen bonding.…”

Section: Fig 2 Representative Glyoxal Hydrates In Aqueous Solutionmentioning

confidence: 55%

“…7). The spectrum resembles that of ice tholin II where glycerol and other alcohols formed upon irradiation (McDonald et al 1996). The major peak is a strong and broad O-H stretching band centered at 3372 cm -1 .…”

Section: Figmentioning

confidence: 82%

“…If polyalcohols were formed in oxygen-containing tholins, such molecules could have been delivered to the early Earth by cometary or meteoritic impacts (McDonald et al 1996). Such polyalcohols, glycerol in particular, yet achiral structures, were once proposed as surrogates for pentoses in acyclic nucleotide analogs (Joyce et al 1987, Joyce 1989, Schwartz 1993.…”

Section: Resultsmentioning

confidence: 99%

“…The resulting ice tholins were analyzed by Sagan and associates through GC-MS, who found a wide range of polyalcohols, including ethylene glycol and glycerol, along with ethers, esters, carbonyls, and organic acids (McDonald et al 1996). Polyoxymethylenes, generated by polymerization of formaldehyde, could not be detected, although the presence of ether linkages make them more volatile than higher alcohols containing OH groups bound by intermolecular hydrogen bonding.…”

Section: Introductionmentioning

confidence: 99%

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On the Plausibility of Pseudosugar Formation in Cometary Ices and Oxygen-rich Tholins

Lavado¹,

Авалос²,

Babiano³

et al. 2015

Orig Life Evol Biosph

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We revisit herein the formation and structure of dihydroxy dioxanes, which can be obtained from prebiotically available precursors and can be regarded as primeval sugar surrogates. Previous studies dealing with the heterogeneous composition of interstellar bodies point to the existence of significant amounts of small polyalcohols along with oxygen-containing oligomers. Even though such derivatives did not give rise to nucleosides and oligonucleotides, nor they were incorporated into subsequent metabolic routes, molecular chimeras based on sugar-like species could be opportunistic scaffolds in pre-evolutionary scenarios. We could figure out that pseudosugars, assembled by hemiacetalic bonds from available precursors in both interstellar and terrestrial scenarios, were presumably more abundant than thought. Moreover, these species share some key features with naturally-occurring sugar rings, such as anomeric preferences, coordinating ability, and the prevalent occurrence of racemic compounds.

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Electrical Properties of Tholins and Derived Constraints on the Huygens Landing Site Composition at the Surface of Titan

et al. 2018

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In 2005, the complex permittivity of the surface of Saturn's moon Titan was measured by the PWA‐MIP/HASI (Permittivity Wave Altimetry‐Mutual Impedance Probe/Huygens Atmospheric Structure Instrument) experiment on board the Huygens probe. The analysis of these measurements was recently refined but could not be interpreted in terms of composition due to the lack of knowledge on the low‐frequency/low‐temperature electrical properties of Titan's organic material, a likely key ingredient of the surface composition. In order to fill that gap, we developed a dedicated measurement bench and investigated the complex permittivity of analogs of Titan's organic aerosols called “tholins.” These laboratory measurements, together with those performed in the microwave domain, are then used to derive constraints on the composition of Titan's first meter below the surface based on both the PWA‐MIP/HASI and the Cassini Radar observations. Assuming a ternary mixture of water ice, tholin‐like dust and pores (filled or not with liquid methane), we find that at least 10% of water ice and 15% of porosity are required to explain observations. On the other hand, there should be at most 50–60% of organic dust. PWA‐MIP/HASI measurements also suggest the presence of a thin conductive superficial layer at the Huygens landing site. Using accurate numerical simulations, we put constraints on the electrical conductivity of this layer as a function of its thickness (e.g., in the range 7–40 nS/m for a 7‐mm thick layer). Potential candidates for the composition of this layer are discussed.

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Production and Chemical Analysis of Cometary Ice Tholins

Cited by 68 publications

References 9 publications

Ethylene glycol in comet C/1995 O1 (Hale-Bopp)

Ethylene glycol in comet C/1995 O1 (Hale-Bopp)

On the Plausibility of Pseudosugar Formation in Cometary Ices and Oxygen-rich Tholins

Electrical Properties of Tholins and Derived Constraints on the Huygens Landing Site Composition at the Surface of Titan

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