Exploring the impact of Stellar Multiplicity on planet formation Across Disc Evolution – Stellar-MADE

ABSTRACT. In regions of active star formation, the protoplanetary discs around young stars act as planetary factories. Recent observing campaigns have shown that the majority of protostars belong to multiple stellar systems: the younger the stars, the higher the degree of multiplicity. Young discs are then strongly affected by stellar multiplicity, unavoidably modifying the way in which planets form. The detailed evolution of multiple systems with discs and planets however remains to be explored. Since most current models have been designed for single stars, there is an urgent need to extend these models to multiple stars. This will pave the way for a better understanding of the process of planet formation within our galaxy.

The Stellar-MADE project aims to provide a comprehensive view of disc dynamics and planet formation within multiple stellar systems. My team and I will thoroughly study multiples to:
(1) Establish the formation channels of protoplanetary discs around young stellar objects;
(2) Follow disc dynamics and grain growth in order to identify the regions of planetesimal formation;
(3) Characterise planetary architectures and the resulting exoplanet population.

To achieve our goals we will perform hydrodynamical and N-body simulations, developing and adapting state-of-the-art codes (Phantom, mcfost, Rebound). Our calculations will include a broad range of physical processes: disc thermodynamics, radiative transfer, gravitational perturbations, aerodynamic friction, dust growth, and Mean-Motion Resonances. This will allow us to identify and quantify stellar multiplicity effects across evolution. My previous work on binary stars constitutes proof-of-concept that it is possible to coherently connect protoplanetary disc evolution to planetary architectures. Unveiling the effects of stellar multiplicity on planet formation will be a major breakthrough.

PROJECT OBJECTIVES. The aim of this project is to study the impact of stellar multiplicity on planet formation: from the onset of disc formation in gaseous clouds to the final stage where stars host stable planetary systems. Three scientific questions will drive the proposed investigation:
i) What are the initial protoplanetary disc conditions around young stellar multiple objects?
ii) Where do solid bodies and planetesimals grow within discs in multiple stellar systems?
iii) What are the most stable planetary architectures in multiple stellar systems?

SCIENTIFIC IMPACT. This project will unveil the effects of stellar multiplicity on planet formation, which will allow us to interpret the whole exoplanetary population under a new prism. Our expected results will become the stepping stone for future research on multiple stellar systems. As a matter of fact, stellar multiplicity is the norm – rather than the exception – in active star-forming regions. It is therefore key to understand the impact of stellar multiplicity on planet formation. The ground- breaking nature of this proposal will guarantee a high impact at the international level, placing the Stellar- MADE team at the forefront of the emerging field of research on disc and planet dynamics in multiples. Our results are expected to open new avenues for studying the disc chemical reservoir across stellar evolution, planetesimal formation, and its impact on exoplanet composition.