Beyond Five Scale Heights: Composition- and Cloud-dependent Ariel Tier-2 Requirements for sub-Neptunes
The Ariel Mission Candidate Sample (MCS) Tier-2 requirements provide a common screening reference by assuming a clear H$_2$/He atmosphere and a five-scale-height transmission signal. We quantify how those requirements change for 197 known planets with $1.5\leq R_{\rm p}/R_\oplus<4.0$ when composition and clouds are specified...