1. The GAPS Programme at TNG LV. Multiple molecular species in the atmosphere of HAT-P-11 b and review of the HAT-P-11 planetary system
- Author
-
Basilicata, M., Giacobbe, P., Bonomo, A. S., Scandariato, G., Brogi, M., Singh, V., Di Paola, A., Mancini, L., Sozzetti, A., Lanza, A. F., Cubillos, P. E., Damasso, M., Desidera, S., Biazzo, K., Bignamini, A., Borsa, F., Cabona, L., Carleo, I., Ghedina, A., Guilluy, G., Maggio, A., Mainella, G., Micela, G., Molinari, E., Molinaro, M., Nardiello, D., Pedani, M., Pino, L., Poretti, E., Southworth, J., Stangret, M., and Turrini, D.
- Subjects
Astrophysics - Earth and Planetary Astrophysics - Abstract
The 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., Comment: 25 pages, 19 figures, accepted for publication in Astronomy & Astrophysics (A&A) journal. Version corrected by the language editor, title edited
- Published
- 2024
- Full Text
- View/download PDF