University of Illinois Urbana-Champaign

Laboratory Simulations Of Titan's Surface Composition And Its Relation To Atmospheric Haze Layers

Sebree, Joshua A.

Content Files
FE02_Abstract.pdf
FE02_Abstract.txt
FE02_Presentation.pptx

Permalink

https://hdl.handle.net/2142/50842

Description

Title
Laboratory Simulations Of Titan's Surface Composition And Its Relation To Atmospheric Haze Layers
Author(s)
Sebree, Joshua A.
Contributor(s)
  • Brinckerhoff, William B.
  • Anderson, Carrie M.
  • Loeffler, Mark
  • Getty, Stephanie A.
  • Pinnick, Veronica T.
  • Li, Xiang
  • Trainer, Melissa G.
  • Schmitt, Angela M.
Issue Date
2014-06-20
Keyword(s)
Planetary atmospheres
Date of Ingest
  • 2014-09-17T16:55:08Z
  • 2015-04-14T18:40:44Z
Abstract
The arrival of the Cassini spacecraft in orbit around Saturn has led to the discovery of benzene at ppm levels, as well as large positive ions evocative of polycyclic aromatic hydrocarbons (PAHs) in Titan’s atmosphere. Recently, the assignment of the band at 3.28 $\mu$m as observed by the Visual–Infrared Mapping Spectrometer (VIMS) to gas-phase PAHs provides further evidence that these molecules are prevalent on Titan. These observations suggest that aromatic reaction pathways play an important role in the photochemistry of Titan’s atmosphere, in particular in the formation of large organic species. These aerosols eventually settle out of the atmosphere onto the surface of Titan giving rise to the different surface albedos that are observed by the VIMS instrument onboard Cassini. We will present results from a laboratory study of the UV irradiation of ppm-level aromatic precursors to understand their influence on the observable characteristics of Titan’s surface. Spectroscopic measurements of our analog aerosols compare favorably to observations of Titan’s haze by VIMS and by the Composite Infrared Spectrometer (CIRS) in the far-infrared. In addition, the broad aerosol emission feature centered at approximately 145 \wn is of particular interest. From the broadness of this feature, we speculate that the emission is a blended composite of low-energy vibrations of large molecules such as polycyclic aromatic hydrocarbons (PAHs) and their nitrogen containing counterparts, polycyclic aromatic nitrogen heterocycles (PANHs). A further comparison of our aerosol spectra to the surface observations carried out by Cassini also shows a strong correlation between the aerosol makeup and the surface albedo of Titan. Using laser desorption mass spectrometry (LDMS) and collision-induced dissociation (CID) MS/MS techniques we confirm the presence of large (5+ rings) PAHs/PANHs in our aerosols and discuss possible formation pathways.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
English
Permalink
http://hdl.handle.net/2142/50842
DOI
https://doi.org/10.15278/isms.2014.FE02
Copyright and License Information
Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

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Abstracts & Presentations - 2014 International Symposium on Molecular Spectroscopy PRIMARY