Extrasolar multi-planet systems are key to advancing our understanding of the Solar System’s formation and the broader processes of planetary formation and evolution. The EXO-RESTART (EXOplanetary dynamics and stability: Reverse Engineering of STable multiplanetary ARchitecTures) project was initiated at Sofia University, Bulgaria, its main focus being on systematically re-examining the statistical and physical features of both previously known and newly discovered multi-planet systems.

Current characterization techniques, such as the reliance on multi-Keplerian models that overlook planetary dynamics or the inconsistent use of stability criteria, introduce biases that hinder theoretical progress in the field. A better understanding of planet formation requires analyzing the dynamical properties of these systems, such as the osculating orbital parameters, rather than the Keplerian best-fit parameters commonly used in studies.

EXO-RESTART aims to address these biases by using advanced numerical methods to investigate planetary formation and evolution. The immediate goal is to conduct the first consistent dynamical modeling of high-precision Doppler and transit photometry data for multi-planet systems, complemented by comprehensive long-term stability analysis to uncover their current dynamical architecture. Ultimately, the project seeks to run simulations of planet migration and planet-planet scattering, exploring the formation processes of high-order mean motion resonance (MMR) systems, eccentric multi-planet systems, and circumprimary planets in close binary systems, which remain underexplored. These efforts aim to reveal the early planet-disk conditions that shaped the planetary systems we observe today.