HTLup B spectrum estimates by the SGF (in blue) and LPM (in orange) methods. The H_α, H_β, and [OI] lines as well as the CaII infrared triplet are detected by the SGF method. Absorptions of TiO and Na are revealed by the LPM method in addition, thanks to its greater preservation of the continuum. On the contrary, it reveals the absence of any VO absorptions, suggesting that the star should be a late-M type. Further improvements of the LPM method are planned to improve the continuum recovery and its quantification (see Sect. 4.2) so that it would be indeed usable for physical interpretations. Yet, a more complex study is beyond the scope of this paper, which is primarily focused on the H_α line (or, similarly, any other emission line).