Seminars at FGG
Occurrence rates of Solar System-type architectures across spectral types: a multi-technique approach
Speaker: Matteo Pinamonti (INAF - Osservatorio di Torino (Italy))
Date and time: 2023-08-10 12:30
Despite being the most abundant classes of known exoplanets, super-Earths and sub-Neptunes are absent in our Solar System, and the exact reason for this is still unknown. However, some models suggest that cold-Jupiter planets prevent the formation of inner super Earths, and that this could be in fact the reason for their absence in our Solar System. In this framework, we take advantage of high-resolution echelle spectroscopy from HARPS-N@TNG, and high-precision astrometric data from Gaia to study planetary systems across different spectral types. First we present the high-cadence and high-precision Radial Velocity (RV) monitoring of stellar hosts to long-period giants with well-measured orbits, in search for short-period low-mass planets, conducted with HARPS-N over a large sample stars, from M-dwarf to Solar-type stars. We then present the combination of RV measurements and high-precision Gaia astrometry, that can greatly expand our knowledge of the long-period planets orbiting the observed systems. We show how the combination of RV information with proper-motion anomalies from GaiaDR3 and Hipparcos can measure the inclination and real masses of several long-period companions in our observed systems, and present a novel set of simulations of Gaia DR4 astrometric time series that, when combined with the RV data at our disposal, quantify the great boost in precision that these data will bring to the study of long-period exoplanetary companions. Finally, from an homogeneous Bayesian analysis of the observed sample, we highlight a very different behavior between G- and M-dwarfs: in the G-sample, the frequency of Super-Earths appears to be diminished by the presence of cold Jupiters, while the opposite is observed for M dwarfs. The presented results provide an important advancement in discriminating between proposed outcomes of different processes for the formation of super Earths in the presence of outer giant companions, and produce the first direct observation of a different influence of cold Jupiters in the formation of planetary systems around stars of different masses.