YSES1 b spectrum estimates, by the SGF (in blue) and LPM (in orange) methods. Left: zoom in on 821 channels around the H_α line. The self-subtraction caused by the SGF method as well as its correction by the proposed LPM method are visible. Two HeI lines are also revealed. Right: zoom in on 821 channels around the CaII infrared triplet. The self-subtraction around the lines is less visible here, because both the lines are weaker and the continuum is (likely) stronger at these wavelengths (yet, in turn, the heights of the lines are theoretically further underestimated); the mask used by the LPM method during this estimation process was adapted to cover the full triplet. A noticeable Na absorption is also revealed.