Speaker
Description
In this talk, I will present a summary of the observational efforts to characterise the planets that could be observed by Ariel and how these studies can support the selection of the future Ariel targets.
In particular, I will present the "Ariel Masses Survey (ArMS)" with the HARPS-N spectrograph at the Telescopio Nazionale Galileo, which is a five-year large program dedicated to the radial velocity monitoring of stars hosting transiting planets with radii spanning the so-called "Radius Valley" (1.3 – 2.5 $R_{\text{Earth}}$). These types of objects belong to the transition region between super-Earths and sub-Neptunes and may show very different internal and atmospheric composition. Up to now, the mechanisms behind their observed diversity are still not understood, partly because a robust knowledge of their planetary mass is not easy to obtain, due to the presence of additional companions or stellar activity signals. A reliable mass determination is also crucial in the context of Ariel, to obtain a robust retrieval of the chemical species and atmospheric properties of these planets. Placed within the activities of the Ariel Consortium Mass Determination WG and as part of the Italian GAPS Collaboration, ArMS is starting to deliver the first mass measurements of sub-Neptune planets hosted by single or multi-planet systems. Our program also includes simulations of the atmospheres of the analyzed planets, and thus provides useful information regarding the selection of the most suitable targets for future observations with Ariel.