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

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 ± 0.08)%.

C. Richard (ICB), V. Boudon (ICB), L. Manceron (LISA (UMR_7583)), J. Vander Auwera (ULB, SQUARES), S. Vinatier, B. Bézard, 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
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