The discoveries of the first planets outside the Solar System in the 1990s opened the completely new
research topic of exoplanetary science. Since then, the existence of over 4300 exoplanets has been
confirmed and exoplanetary science has become one of the main branches of astrophysics.
Exoplanets are discovered with several techniques providing complementary information on the
objects: transit photometry can unveil the planet’s radius, while the radial velocity technique can give
estimates of the planet’s mass. New insights on exoplanet characterization will soon come also from
space missions like TESS, CHEOPS (already online) and JWST and PLATO (planned).
However, two of the most critical aspects of exoplanetary systems remain very difficult to assess:
1) The magnetisation of exoplanets, which plays a central role in planetary habitability. A planetary
magnetic field shields the planetary surface from the destructive flux of charged particles of stellar
winds, so that life can evolve. Knowing planetary magnetism it is necessary to understand exoplanetary
climates and address exoplanetary habitability.
2) The interaction between the planet and its host star, which is mediated by gravitation, radiation,
magnetic fields, and the stellar wind. While it is clear that these star-planet interactions (SPIs) affect the
planet, it is unclear whether they have an observable effect on the star. Understanding the physics
governing SPIs is essential to push exoplanetary science into the next era.
REVErSI is an ambitious project that aims to provide access to these two characteristics for the first
time. By developing analytical and numerical models of SPIs, and constraining them on available stellar
observables, this project unravels the effect of magnetic and tidal SPIs on the activity of the
host star. As a second step, REVErSI will use models of magnetic SPI to predict the magnetic field
strength of some exoworlds.
Being able to characterize exoworlds is central for the human need of exploring and discovering the universe. Ask any kid around the world, or almost any kid, and they are fascinated by understanding remote areas of the universe where, possibly, life exists. This project is a step in this direction.
