The D/H ratio in Titan's acetylene from high spectral resolution IRTF/Texes observations - Observatoire de Paris Access content directly
Conference Papers Year : 2022

The D/H ratio in Titan's acetylene from high spectral resolution IRTF/Texes observations

Abstract

<p>In July 2017, we used the Texes high-resolution spectrometer at the NASA Infrared Telescope Facility to observe Titan in the 19.3-&#181;m (519 cm<sup>-1</sup>) region where the &#957;<sub>4</sub> band of deuterated acetylene (C<sub>2</sub>HD) is located. Six individual lines were clearly detected with a S/N ratio up to 10. Spectral intervals around 8.0 (745 cm<sup>-1</sup>) and 13.4 &#181;m (1247 cm<sup>-1</sup>) were observed during the same run to constrain the disk-averaged temperature profile and acetylene (C<sub>2</sub>H<sub>2</sub>) abundance profile respectively. Telluric correction and flux calibration were obtained from observations of asteroid Hygiea. Constraints from Cassini/CIRS observations in 2017 around the sub-Earth latitude were also used to constrain the atmospheric model and check the flux calibration. The D/H ratio is derived from the C<sub>2</sub>HD/C<sub>2</sub>H<sub>2</sub> abundance ratio. Preliminary results of this analysis indicate a D/H ratio in acetylene around 1.7&#215;10<sup>-5</sup> with an uncertainty of about 10%, in agreement with the previous, less precise, determination from Cassini/CIRS measurements. This ratio is slightly larger than that in methane (approximately 1.3&#215;10<sup>-5</sup>), which suggests some fractionation at work in the photochemical production of acetylene from methane.</p>
No file

Dates and versions

obspm-03904128 , version 1 (16-12-2022)

Identifiers

Cite

Bruno Bézard, Sandrine Vinatier, Tommy Greathouse, Rohini Giles, Conor Nixon, et al.. The D/H ratio in Titan's acetylene from high spectral resolution IRTF/Texes observations. Europlanet Science Congress 2022, Sep 2022, Grenade, Spain. ⟨10.5194/epsc2022-363⟩. ⟨obspm-03904128⟩
11 View
0 Download

Altmetric

Share

Gmail Facebook X LinkedIn More