Seminars at FGG
Characterising young Exoplanets and their host stars
Speaker: Simone Filomeno (INAF - Osservatorio Astronomico di Roma (Italy))
Date and time: 2023-08-31 12:30
It is currently known that planets form within a few million years of star formation. Consequently, stars and planets are interconnected, and precise and homogeneous measurements of stellar parameters and abundances are essential for the accurate characterization of the properties of planets belonging to the system. For young stars (<1Gyr), there are not yet many systematic studies characterizing them and understanding the correlations between their properties and those of the planetary environment at the first evolutionary stages of the system. This work is going towards that direction and the results that will be obtained will help to clarify how much the young stellar environment affects the planetary formation process, the timescales of evolution, and the relationship with diverse typesof planets (e.g., super-Earths, sub-Neptunes). The goal of this work is to characterize a sample of 11 young transiting planet host stars, observed as part of the Global Architecture of Planetary System program, homogeneously and accuratelyby deriving stellar parameters (effective temperature, surface gravity, rotation speed), elemental abundances of 18 elements (light, iron-peak, alpha-, s-process...) and discuss them in the context of planetary formation. The analysis is mainly based on the use of high-resolution HARPS-N@TNG spectra of targets with temperatures higher than 5000K and projected rotational speed (vsini) of less than 10 km/s. Both methods based on line equivalent widths (EWs) and spectral synthesis are used to derive stellar parameters and elemental abundances. We are also deriving star ages by exploiting a new method which makes use of lithium EWs and the effective temperature of the star. Among the first results obtained, all elemental abundances are compatible with solar and older stars' abundances analysed by Biazzo et al. (2022). All targets with measured C and O abundances show compatibility with silicate planets. In the future, we will study more systematically the correlation between stellar abundances and planetary parameters, such as mass, eccentricity, and density. In addition, we will investigate the possibility of these stars to provide information on planetary abundances. Finally, we will attempt to trace the scenario of planetary migration.