Planetary systems at young ages are valuable resources that can help us to understand formation and migration processes, the physical evolution of the planet themselves (e.g., gravitational contraction), and the atmospheric evaporation under high-energy irradiation. Early planet-searching surveys generally avoided young stars, since their strong and variable stellar activity poses a serious challenge to exoplanet detections. However, with the continuous development of high-precision instruments and advanced analyses techniques, more and more observations of young planets have been recently gathered, leading to many interesting results and discoveries. This fastly developing field of research is earning an ever increasing interest from the community, attracting more and more people, working with different techniques and tackling this problem from different points of view. The study of young exoplanetary systems can help us understand the general population of observed exoplanets, since theoretical evolution models suggest that several of its main features, such as the 'hot Neptunian desert' and the 'radius valley', are caused by physical mechanisms that occur during the first millions of years of evolution. However, these models are always, to some extent, degenerated with their initial conditions, which are, in turn, set by the parameters of young planetary systems, which remain poorly constrained. This way, the same features of the planetary population can be feasibly explained through the work of very different physical processes - for various assumptions on the properties of young systems. The goal of this session is to bring together different people working on the fascinating and complex topic of close-in exoplanets orbiting young stars, to facilitate the discussion between different groups across Europe and beyond, and the exchange of expertise between observers and theorists. In particular, within the context of the search and characterization of close-in planets around young stars, the Session will focus on these three major topics:

• Detection of close-in young exoplanets via the Radial Velocity (RV) and transit methods. Thanks to dedicated space missions such as Kepler and TESS, many transiting exoplanets have been discovered orbiting young stars during the recent years. Observing such planets at different ages offers the opportunity to observe how the planetary orbit and internal structure evolves with time, after dissipation of the protoplanetary disk. However, observing planetary signatures around young stars is a challenging task due to the strong stellar activity, particularly in the framework of RV follow-ups aiming to measure the planet mass. Therefore, their treatment requires state-of-the-art techniques tailored to disentangle planetary and stellar signals.
• Atmospheric characterization of young exoplanets with high- and low-resolution spectroscopy. Atmospheric characterization is a key element in the detailed study of young close-in planets: although mainly possible to date for giant planets, it allows us to study in detail the chemical composition of their outer layers, and offers a unique opportunity to help solving the puzzle of the formation and migration of close-in giant planets, because different formation and evolution channels leave different imprints in the physical and chemical properties of the planetary atmospheres. It also allows us to gather direct measurements of ongoing atmospheric escape, testing the mechanisms governing planetary evolution.
• Theoretical modeling of early planetary evolution and star-planet interactions. To complete the well-rounded study of young close-in exoplanets, the theoretical modeling cannot be ignored: the physical processes driving the dynamics of young planets and the evolution of their atmospheres are thought to be different from those occurring at later ages, due to their specific conditions, set by both the host stars (e.g. strong variability, stellar winds, X-ray emission) and the planets themselves (e.g. large internal energy budget). Therefore, a more specialized theoretical approach is required to model such planets, in particular for the exploitation and interpretation of observational data.

Programme

The Session is scheduled for Friday, July 5th, 2024. The Session will be divided into three blocks, each of them covering one of the main topics:

• Detection of close-in young exoplanets;
• Atmospheric characterization of young exoplanets;
• Theoretical modeling of early planetary evolution.

Invited speakers

• Alejandro Suárez Mascareño (Instituto de Astrofísica de Canarias, Spain)
• Antonija Oklopčić (Universiteit van Amsterdam, Netherlands)
• Adina Feinstein (University of Colorado Boulder, USA)

Scientific organisers

• Matteo Pinamonti, chair (INAF-Osservatorio Astrofisico di Torino, Italy)
• Ilaria Carleo, co-chair (Instituto de Astrofísica de Canarias, Spain)
• Oscar Barragán (University of Oxford, UK)
• Serena Benatti (INAF-Osservatorio Astronomico di Palermo, Italy)
• Aline Vidotto (Leiden Observatory, Netherlands)
• Felipe Murgas (Instituto de Astrofísica de Canarias, Spain)
• Daria Kubyshkina (Austrian Academy of Sciences, Austria)
• Elisabeth R. Newton (Dartmouth College, USA)
• Michael Zhang (University of Chicago, USA)
• Domenico Nardiello (INAF-Osservatorio Astronomico di Padova, Italy)

Contact

Please contact Dr. Matteo Pinamonti (matteo.pinamonti @ inaf.it) for any questions about this Special Session.