“IDENTIFICAÇÃO E CARACTERIZAÇÃO DE EXOPLANETAS ROCHOSOS ASTROBIOLOGICAMENTE INTERESSANTES”

Abstract

The primary objective of this dissertation is the search for astrobiologically interesting rocky exoplanets through the characterization of their physical and orbital parameters, as well as their positions within the Habitable Zone (HZ) of their host stars. Physical parameters and the HZ were calculated for a sample of more than 6,000 exoplanets available in the NASA database (NASA Exoplanet Archive). The calculations were performed using codes developed by the author of this research together with a one-dimensional radiative-convective climate model (ATMOS). By combining the climate model with the orbital distances of the planets, it is possible to infer their likely atmospheric composition, as well as assume their surface temperature and surface pressure. These parameters make it possible to rank exoplanets according to their Earth Similarity Index (ESI). Two samples with distinct limiting physical parameters were analyzed: Rocky Planets Including Super-Earths/Hycean Planets and Small Rocky Planets. A total of 1,447 Small Rocky Exoplanets (0.1 M⊕ < Mp < 4.37 M⊕ or 0.1 R⊕ < RP < 1.64 R⊕) were compiled. Of these, 44 are located within the Optimistic Habitable Zone, and 26 within the Conservative Habitable Zone. By following the ATMOS model, 25 of these exoplanets were classified within the Conservative Habitable Zone, of which 20 are consistent with a possible Earth-like atmosphere and 15 exhibit an ESI > 0.8. Further, a total of 1,161 Rocky Super-Earth/Hycean Exoplanets (4.37 M⊕ < MP < 10 M⊕ or 1.64 R⊕ < RP < 2.5 R⊕) were compiled. Of these, 31 are located within the Optimistic Habitable Zone, and 14 within the Conservative Habitable Zone. By following the ATMOS model, 14 of these exoplanets were classified within the Conservative Habitable Zone, of which 15 are consistent with a possible Earth-like atmosphere and 9 exhibit an ESI > 0.8. The analysis identifies eight exoplanets with surface temperatures capable of sustaining liquid water: GJ 1002b, GJ 180c, GJ 433d, Kepler-1652b, Kepler-22b, Kepler-442b, Kepler-443b, and TOI-700d. Only two of these are classified as Super-Earth/Hycean planets: Kepler-22b and Kepler-443b. Nearly all exhibit an ESI > 0.8, with the sole exception of Kepler-443b. Among them, GJ 1002b stands out as the most promising candidate because of its strong similarity to Earth across the four parameters used in the ESI calculation. The results reinforce the potential of rocky planets located within habitable zones as priority targets for future observations with instruments such as the JWST (James Webb Space Telescope) and high-resolution spectrographs. At the same time, they highlight methodological limitations that should be addressed, including the need for a broader range of atmospheric models and more accurate mass-radius relationships.