Titan

Self and N2 Collisional Broadening Of Far-infrared Methane Lines At Low-temperature With Application To Titan

By Keith Cowing
Status Report
astro-ph.EP
July 5, 2023
Filed under , , ,
Self and N2 Collisional Broadening Of Far-infrared Methane Lines At Low-temperature With Application To Titan
Analysis of the R(11) region of the far-infrared spectrum of 12CH4, taken at room temperature with a mixture of nitrogen at 133 mbar (see Ref. [13]). The observed spectrum is shown in the upper part, in red and the fitted spectrum in blue. The fit residuals are presented in the lower panel. A water vapor line, included in the fit, is also identified. astro-ph.EP

We report the measurement of broadening coefficients of pure rotational lines of methane at different pressure and temperature conditions.

A total of 27 far-infrared spectra were recorded at the AILES beamline of the SOLEIL synchrotron at room-temperature, 200 K and 120 K, in a range of 10 to 800 mbar. Self and N 2 broadening coefficients and temperature dependence exponents of methane pure rotational lines have been measured in the 73-136 cm –1 spectral range using multi-spectrum non-linear least squares fitting of Voigt profiles.

These coefficients were used to model spectra of Titan that were compared to a selection of equatorial Cassini/CIRS spectra, showing a good agreement for a stratospheric methane mole fraction of (1.17 Ā± 0.08)%.

C. Richard (ICB), V. Boudon (ICB), L. Manceron (LISA (UMR_7583)), J. Vander Auwera (ULB, SQUARES), S. Vinatier, B. BĆ©zard, M. Houelle (ObsGE)

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2307.00810 [astro-ph.EP] (or arXiv:2307.00810v1 [astro-ph.EP] for this version)
Journal reference: Icarus, inPress, pp.115692 (2023)
Related DOI:
https://doi.org/10.1016/j.icarus.2023.115692
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Submission history
From: Richard Cyril [via CCSD proxy]
[v1] Mon, 3 Jul 2023 07:49:51 UTC (336 KB)
https://arxiv.org/abs/2307.00810
Astrobiology

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Naā€™Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) šŸ––šŸ»