Characterizing the atmospheres of the two warm Neptune-liked planets HD 106315 c and HD 3167 c with the HST/WFC3 Camera

We present an atmospheric characterization of two intermediate-sized planets: HD 06315c (RP=4.98±0.23 R⊕) and HD3167c (RP=2.74±0.11 R⊕) whose results have been published in the ARES IV article, i.e Guilluy et al 2020. We analyzed spatially scanned spectroscopic observations obtained with the G141 grism (1.125 - 1.650 μm) of the Wide Field Camera 3 (WFC3) onboard the Hubble Space Telescope. We use the publicly available Iraclis pipeline and TauREx3 atmospheric retrieval code and we found a strong water spectroscopic signature in HD 106315 c transmission spectrum corresponding to an abundance of log (H2O)=2.1±0.7 (5.7σ). We also found evidences of water and carbon dioxide in HD 3167 c' s atmosphere with log (H2O)=4.1±0.9 (3.2σ) and log (CO2)=2.4±0.7 (3.3σ). Different scenarios including additional contribution of clouds, ammonia and carbon bearing species are discussed. HD 106315 c and HD3167c will be interesting targets for upcoming telescopes such as the James Webb Space Telescope (JWST) and the Atmospheric Remote-Sensing Infrared Exoplanet Large- Survey (ARIEL).