Can laboratory tholins mimic the chemistry producing Titan's aerosols? A review in light of ACP experimental results

Coll, Patrice; Navarro‐González, R.; Szopa, Cyril; Poch, Olivier; Ramírez, Sandra I.; Coscia, David; Raulin, F.; Cabane, Michel; Buch, Arnaud; Israël, G.

doi:10.1016/j.pss.2012.07.006

Cited by 53 publications

(46 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5 compared to the residue obtained after C 4 N 2 irradiation and tholins generated by different methods. Our HC 5 N residue spectrum presents common tholin absorption bands (Coll et al 2013;Imanaka et al 2004Imanaka et al , 2012CouturierTamburelli et al 2014a;Gudipati et al 2013). We can observe the presence of intense and broad bands in the νNH stretching area due to the presence of amines functions (∼3250 cm −1 ).…”

Section: Infrared Spectrum Of the Hc 5 N Residuesupporting

confidence: 60%

Simulation of Titan’s atmospheric photochemistry

Couturier-Tamburelli

Piétri

Gudipati

2015

A&A

View full text Add to dashboard Cite

We studied the photochemistry of frozen ice of a polar Titan's atmospheric molecule cyanodiacetylene (HC 5 N) to determine the possible contribution of this compound to the lower altitude photochemistry of haze layers found on Titan. We used infrared analysis to examine the residue produced by irradiation of solid HC 5 N at λ > 300 nm. The resulting polymer is orange-brown in color. Based on theoretical analysis and the general tendency of HC 5 N and C 4 N 2 to undergo similar ice photochemistry at longer wavelengths accessible in Titan's lower atmosphere, we conclude that Titan's lower atmosphere is photochemically active in the regions of cloud, ice, and aerosol formation. C 4 N 2 is a symmetric molecule with no net dipole moment whereas, HC 5 N has a large dipole moment of ∼4 D. Consequently, though both these molecules have very similar molecular weight and size, their sublimation temperatures are different, HC 5 N subliming around 170 K compared to 160 K for C 4 N 2 . Based on our studies we conclude that in Titan's atmosphere the cyanoacetylene class of molecules (HCN, HC 3 N, HC 5 N, etc.) would condense first followed by the dicyanoacetylenes (C 2 N 2 , C 4 N 2 , C 6 N 2 , etc.), leading to fractionation of different class of molecules. From the fluxes used in the laboratory and depletion of the original HC 5 N signals, we estimate Titan's haze ice photochemistry involving polar nitriles to be significant and very similar to their non-polar counterparts.

show abstract

Section: Infrared Spectrum Of the Hc 5 N Residuesupporting

confidence: 60%

Simulation of Titan’s atmospheric photochemistry

Couturier-Tamburelli

Piétri

Gudipati

2015

A&A

View full text Add to dashboard Cite

show abstract

“…Laboratory studies have formed tholins in a N2/CH4 gas mixture by electron discharge and photochemistry (Cable et al, 2012;Coll et al, 2013). A range of nitrogen-rich organics and hydrocarbons are present in the tholin-like material, suggesting that co-polymerization or incorporation of small precursors (such as C2H2) is occurring.…”

Section: Titanmentioning

confidence: 99%

Uptake of acetylene on cosmic dust and production of benzene in Titan's atmosphere

Frankland

James

Carrillo‐Sánchez

et al. 2016

Icarus

View full text Add to dashboard Cite

A low-temperature flow tube and ultra-high vacuum apparatus were used to explore the uptake and heterogeneous chemistry of acetylene (C2H2) on cosmic dust analogues over the temperature range encountered T below 600 km. The uptake coefficient, , was measured at 181 K to be (1.6 ± 0.4) × 10 -4 , (1.9 ± 0.4) × 10 -4 and (1.5 ± 0.4) × 10 -4 for the uptake of C2H2 on Mg2SiO4, MgFeSiO4 and Fe2SiO4, respectively, indicating that  is independent of Mg or Fe active sites. The uptake of C2H2 was also measured on SiO2 and SiC as analogues for meteoric smoke particles T but was found to be below the detection limit ( < 6 × 10 -8 and < 4 × 10 -7 , respectively). The rate of cyclo-trimerization of C2H2 to C6H6 was found to be 2.6 × 10 -5 exp(-741/T) s -1 , with an uncertainty ranging from ± 27 % at 115 K to ± 49 % at 181 K. A chemical ablation model was used to show that the bulk of cosmic dust particles (radius 0.02 -10  T mass loss through sputtering), thereby providing a significant surface for heterogeneous 2 chemistry. A 1D model of dust sedimentation shows that the production of C6H6 via uptake of C2H2 on cosmic dust, followed by cyclo-trimerization and desorption, is probably competitive with gas-phase production of C6H6 between 80 and 120 km.

show abstract

“…All the pyrolyzers used for space exploration are based on the oven pyrolysis principle whereas flash pyrolyzers (using Curie Point filament for example) are more commonly used in the laboratory (e.g. Coll et al, 2013). In all cases, the sample is automatically collected and transferred to the oven where it is heated to temperatures reaching from 500°C (Viking GCMS experiment) to about 1000°C (Curiosity SAM experiment).…”

Section: Introductionmentioning

confidence: 99%