Stellar and planetary characterization of two Kepler multi-planet systems from high-quality Gem- ini/GRACES spectra

JOFRE, E.; PETRUCCI, R.; SAFFE, C.; MARTIOLI, E.

La Plata

Workshop; Workshop Gemini en Argentina: Actualidad y Prospección; 2018

Our understanding of exoplanets structure, composition, formation and evolution is strongly linked to our knowledge of a series of fundamental parameters of their host stars. On the one hand, there is strongevidence that stellar composition and mass have a major influence in the formation, evolution and architecture of planetary systems. On the other hand, models of planetary structure and composition require accurate estimations of their mass and radii, which for transiting planets, depend critically on the mass and radius of the parent star. These stellar properties, in turn, depend on the atmospheric parameters of the star (effective temperature, surface gravity, and metallicity), which can be derived from high-quality spectra. However, this kind of spectra is notcommonly available for faint planet host stars such as those in the Kepler field. In this context, based on GRACES high resolution and high signal-to-noise ratio spectra obtained at Gemini North, we present detailed chemical abundance analysis of two Kepler evolved objects that host multi-planet candidates. We determine atmospheric parameters and chemical abundances of 25 elements from equivalent widths and synthesis analysis. In addition, from the new precise atmospheric parameters, we derive refined stellar and planetary physical properties.