Hydrogen cyanide (HCN) may be present in hot Super-Earths with nitrogen-dominated atmospheres and may become a primary specie to be searched for in thermal emission. In this study, we derived an HCN vertical distribution reference for modelling the atmospheres of hot super-Earths or Titan-like exoplanets. Our mean HCN vertical profile reference is based on our measurements of HCN in the most HCN-rich atmosphere in the Solar System, Titan. The measurements consisted of ground-based submillimetre observations acquired quasi-simultaneously with the Herschel ones. We applied a line-by-line radiative transfer code to calculate the synthetic spectra of HCN, and a retrieval algorithm to retrieve the HCN vertical distributions. Our HCN-intercomparisons allowed us also to perform a consistent check between space and ground-based observations and to obtain a profile that could be assimilated into climate models, chemistry calculations, as a guide to understand what to expect in a N-dominated atmosphere, and a reference in preparation for future observations of Titan and Titan-like exoplanets for example.
{"references":["Rengel et al. A&A 658, A88 (2022)"]}