Detection and characterisation of star-planet magnetic interactions

Antoine Strugarek

CEA/Laboratoire Dynamique des Étoiles, Exoplanète et de leur Environnement

Over the last two decades, a large population of close-in planets has been detected around a wide variety of host stars. Such planets are thought to strongly interact with their host star by means of the irradiation they receive, the tidal forces they induce, as well as their interaction with the ambient magnetised stellar atmosphere and wind they orbit in. Can we use these interactions to better constrain these planets and their hosting stars? And where does this population of hot planets originate from? The properties of the host star determine the key ingredients at the heart of these interactions. The stellar spectrum is the primary driver of the interaction in the upper atmosphere of exoplanets. The stellar structure determines its response to the tidal forcing from his hot exoplanet. Finally, the stellar global magnetic field is at the heart of star-planet magnetic interaction: its strength sets the magnetic energy available for the interaction, its shape determines the connection path between the star and the planet, and its temporal modulation (e.g. magnetic cycles) is at the source of an on/off behavior of the magnetic interaction. I will give an overview of our understanding of star-planet magnetic interactions. I will focus on describing short term ?intra-orbit? and long term ?secular? effects of these interactions. I will reflect on our present capability to detect and characterise them, both in individual systems and in the hot exoplanets population. When detected, star-planet interactions indeed provide a fantastic opportunity to better understand the environment of the host star, as well as the properties of the exoplanet triggering them.

Date:	Thursday, 7 December 2023
Time:	11:30
Where:	Université de Montréal
	Pavillon MIL A-3561