SMAUG helps generate infrared spectroscopy data for Hot Jupiter-type exoplanets

Analyzing data on the atmospheric conditions of Hot Jupiter-type exoplanets is extremely complex and often incurs obstacles such as spectral confusion. Dudás et al. developed a diagnostic tool for gathering high-temperature infrared spectroscopy data essential for interpreting the atmospheric properties of Hot Jupiter type exoplanets.

“We developed a highly sensitive device capable of probing methane accelerated to hypersonic speeds, reducing the complexity of the recorded data but preserving the information about the intense molecular vibration,” said author Robert Georges.

The device, known as Spectroscopy of Molecules Accelerated in Uniform Gas flow (SMAUG), uses a small dimension Laval nozzle that can freeze the rotation of molecules without interfering with their vibration, allowing researchers to obtain simpler data and extract precise information on the vibration of the molecules.

Equipped with an isostatic graphite nozzle that can withstand temperatures of up to 2000 kelvins, SMAUG produces non-local thermal equilibrium infrared spectra based on a hypersonic expansion probed by cavity ring-down spectroscopy.

“The information extracted from our spectra will be used to verify and improve the accuracy of the theoretical models used to generate synthetic spectra at high temperatures,” said Georges. “They will be able to feed high-temperature spectroscopic databases made available to the astrophysical community to improve the radiative models that are used to describe the atmospheres of hot Jupiters and hot Neptunes.”

The authors hope to apply this method to other relevant molecules such as ethylene and acetylene, and intend on working with molecular physicists to develop a model capable of accurately simulating the infrared spectrum of methane up to 2000 kelvins.

Source: “High-temperature hypersonic Laval nozzle for non-LTE cavity ringdown spectroscopy,” by Eszter Dudás, Nicolas Suas-David, Shuvayan Brahmachary, Vinayak Kulkarni, Abdessamad Benidar, Samir Kassi, Christine Charles, and Robert Georges, Journal of Chemical Physics (2020). The article can be accessed at https://doi.org/10.1063/5.0003886 .