BASILICATA, MarioMarioBASILICATAGIACOBBE, PaoloPaoloGIACOBBEBONOMO, ALDO STEFANOALDO STEFANOBONOMOSCANDARIATO, GAETANOGAETANOSCANDARIATOBrogi, M.M.BrogiSINGH, VIKASHVIKASHSINGHDI PAOLA, AndreaAndreaDI PAOLAMancini, L.L.ManciniSOZZETTI, AlessandroAlessandroSOZZETTILANZA, Antonino FrancescoAntonino FrancescoLANZACubillos, P. E.P. E.CubillosDAMASSO, MarioMarioDAMASSODESIDERA, SilvanoSilvanoDESIDERABIAZZO, KatiaKatiaBIAZZOBIGNAMINI, ANDREAANDREABIGNAMINIBORSA, FrancescoFrancescoBORSACABONA, LorenzoLorenzoCABONACARLEO, IlariaIlariaCARLEOGHEDINA, AdrianoAdrianoGHEDINAGUILLUY, GloriaGloriaGUILLUYMAGGIO, AntonioAntonioMAGGIOMainella, GiovanniGiovanniMainellaMICELA, GiuseppinaGiuseppinaMICELAMOLINARI, Emilio CarloEmilio CarloMOLINARIMOLINARO, MarcoMarcoMOLINARONARDIELLO, DomenicoDomenicoNARDIELLOPedani, M.M.PedaniPINO, LorenzoLorenzoPINOPORETTI, EnnioEnnioPORETTISouthworth, J.J.SouthworthSTANGRET, Monika BeataMonika BeataSTANGRETTURRINI, DiegoDiegoTURRINI2024-09-242024-09-2420240004-6361http://hdl.handle.net/20.500.12386/35318The atmospheric characterisation of hot and warm Neptune-size exoplanets is challenging due to their small radius and atmospheric scale height. The warm-Neptune HAT-P-11b is a remarkable target for such characterisation due to the large brightness of its host star (V=9.46 mag; H=7.13 mag). The aims of this work are to review the main physical and architectural properties of the HAT-P-11 planetary system, and to probe the presence of 8 molecular species in the atmosphere of HAT-P-11b at high spectral resolution in the near-infrared. The planetary system was reviewed by analysing transits and occultations of HAT-P-11b from the Kepler data set as well as HIRES at Keck archival radial-velocity (RV) data. We modelled the latter with Gaussian-process regression and a combined quasi-periodic and squared-exponential kernel to account for stellar variations on both (short-term) rotation and (long-term) activity-cycle timescales. In order to probe the atmospheric composition of HAT-P-11b, we observed 4 transits of this target with GIANO-B at TNG. We find that the long-period ($P\sim9.3$ years) RV signal previously attributed to planet HAT-P-11c is more likely due to the stellar magnetic activity cycle. Nonetheless, the Hipparcos-Gaia difference in the proper-motion anomaly suggests that an outer-bound companion might still exist. For HAT-P-11b, we measure a radius $R_{\rm p}=0.4466\pm0.0059\,R_{\rm J}$, a mass $M_{\rm p}=0.0787\pm0.0048\,M_{\rm J}$, and an eccentricity $e=0.2577^{+0.0033}_{-0.0025}$, in accordance with values in the literature. Probing its atmosphere, we detect $NH_3$ (S/N$=5.3$, significance$=5.0\sigma$) and confirm the presence of $H_2O$ (S/N$=5.1$, significance$=3.4\sigma$). We also tentatively detect the signal of $CO_2$ (S/N$=3.0$, significance$=3.2\sigma$) and $CH_4$ (S/N$=4.8$, significance$=2.6\sigma$), whose presence need to be confirmed by further observations.STAMPAenArticle10.1051/0004-6361/2023476592-s2.0-85195498763https://www.aanda.org/articles/aa/full_html/2024/06/aa47659-23/aa47659-23.htmlhttp://arxiv.org/abs/2403.01527v3FIS/05 - ASTRONOMIA E ASTROFISICA