Frankland, VL, James, AD, Carrillo Sanchez, JD et al. (4 more authors) (2016) Uptake of acetylene on cosmic dust and production of benzene in Titan’s atmosphere. Icarus, 278. pp. 88-99. ISSN 0019-1035
Abstract
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 en-countered in Titan’s atmosphere below 600 km. The uptake coefficient, γ, 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 γ 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 in Titan’s atmosphere, but was found to be below the detection limit ( γ < 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 μm) entering Titan’s atmosphere do not ablate ( < 1% mass loss through sputtering), thereby providing a significant surface for heterogeneous 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.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016, Elsevier Inc. This is an author produced version of a paper published in Icarus. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Titan, atmosphere; Kuiper belt; Interplanetary dust |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Physical Chemistry (Leeds) |
Funding Information: | Funder Grant number Leverhulme Trust F/00 122/BB EU - European Union 291332 Science & Technology Facilities Council(STFC) ST/L000628/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 14 Jul 2016 08:39 |
Last Modified: | 15 Oct 2017 22:09 |
Published Version: | http://dx.doi.org/10.1016/j.icarus.2016.06.007 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.icarus.2016.06.007 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:102174 |