SPECTROSCOPY OF HYDROCARBONS RELEVANT TO THE ATMOSPHERES OF HOT JUPITER EXOPLANETS IN THE 1.6-1.7 μm RANGE: UNAMBIGUOUS ASSIGNMENT OF ETHYLENE TRANSITIONS

Perot, Solène

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Description

Title

SPECTROSCOPY OF HYDROCARBONS RELEVANT TO THE ATMOSPHERES OF HOT JUPITER EXOPLANETS IN THE 1.6-1.7 μm RANGE: UNAMBIGUOUS ASSIGNMENT OF ETHYLENE TRANSITIONS

Author(s)

Perot, Solène

Contributor(s)

• Georges, Robert
• Rutkowski, Lucile
• Kassi, Samir
• Lecomte, Julien
• Suas-David, Nicolas
• Tyuterev, Vladimir
• Rey, Michael

Issue Date

2023-06-22

Keyword(s)

Mini-symposium: Infrared Spectroscopy in the JWST Era

Abstract

Accurate knowledge of the absorption fingerprint of the species expected in the atmospheres of the hot Jupiter exoplanets is required to allow their detection. Methaneᵃ and acetyleneᵇ were already detected in such environments, and the presence of other small hydrocarbons such as ethylene (C₂H₄) is expected. However, spectral assignment of C₂H₄ transitions is not available at wavenumbers higher than 3500 cm⁻¹, partly due to its highly congested absorption spectrum at room temperature. To provide accurate assignments of the cold transitions, we perform cavity ring-down spectroscopy of a jet-cooled ethylene gas sample in the 1.6-1.7 µm spectral range. The gas contained in a high-pressure reservoir is expanded into a low-pressure chamber through an 8.5cm-long slit with a tunable opening width ranging from 0 to 350 µm. This process induces a simplification of the absorption spectrum by reducing drastically the rotational temperature and by narrowing the absorption line widths. Three spectra were recorded with a vibrational temperature of about 220K but different rotational temperatures: 5K, 35K, and 75K. Unambiguous assignment of the observed lines is performed using the TheoReTS ab initio line listᶜ and the temperature dependence of the transition intensities.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Handle URL

https://hdl.handle.net/2142/122492

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