2022RNAAS...6..129Z

We analyzed archival data of the warm Neptune HD 106315c, an exoplanet with an extended atmosphere orbiting an F-type star with a 21 days period. We used data from the HARPS instrument covering three transits and employed the high-resolution transmission spectroscopy technique. Our analysis yielded a non-detection of sodium with an upper limit of 0.24% on the depth of the planetary feature. This can hint at the presence of Rayleigh scattering in the atmosphere and/or clouds in the upper atmosphere. The HD 106315 system with its two Neptune-sized planets remains an intriguing target for comparative planetology in the starting era of JWST and the upcoming Ariel mission.