Transmission spectrum of WASP-69b

We performed retrievals on the full spectrum with combined stellar activity and planet atmosphere models. We directly detect a facula in the form of a hot spot crossing event in one of the transits and indirectly detect unocculted faculae through an apparently decreasing radius towards the blue end of the transmission spectrum. We determine a facula temperature of {Delta}T=+644^+427^_-263_K for the former and a stellar coverage fraction of around 30% with a temperature of {Delta}T=+231+/-72K for the latter.

The planetary atmosphere is best fit with a high-altitude cloud deck at 1.4mbar that mutes atomic and molecular features. We find indications of water and ammonia with logH_2_O)=-2.01^+0.54^_-0.86_ and log(NH_3_)=-3.4^+0.96^_-5.20_ respectively and place 3{sigma} upper limits on TiO (<10^-7.65^) and K (<10^-7^). We see no evidence of Na which we attribute to the presence of clouds.