Description
The orbital stability of planetary systems is not straightforward because of chaotic diffusion in the orbits. Mean-motion and/or secular resonances can help to stabilize the systems and hence put constraints on their orbital parameters to be determined from the observations.
The remarkable diversity of exoplanetary systems has challenged our understanding of planet formation and evolution. While many systems exhibit orderly, compact architectures, others appear dynamically excited or even sculpted by past instabilities. Interpreting this diversity requires connecting theoretical models of system evolution with emerging observational constraints.
In the first...
Recent works on three-planet mean motion resonances (MMRs) have highlighted their importance for understanding the details of the dynamics of planet formation and evolution. While the dynamics of two-planet MMRs are well understood and approximately described by a one-degree-of-freedom Hamiltonian, little is known of the exact dynamics of three-body resonances besides the cases of zeroth-order...
The ejection of planets by the instability of planetary systems is a potential source of free-floating planets. We numerically simulate multi-planet systems to study the evolution process, the properties of surviving systems, and the statistics of ejected planets. For systems with only super-Earth planets, we find that the time (in units of the orbital period of the innermost planet) for the...
AU Mic is a highly active M dwarf star with an edge-on debris disk and two known transiting sub-Neptunes, with a possible third planetary companion. The two transiting planets exhibit significant transit-timing variations (TTVs). We conducted ultra-high-precision photometric observations with the CHaracterizing ExOPlanet Satellite (CHEOPS) in 2022 and 2023. We combined our new measurements...
In this work, I study the relation between the fixed points of the averaged model and the libration centers of the complete system. I find that while averaged model are good at predicting the libration centers of the complete systems, they are poorly adapted to the computation of ephemeris.
The growing number of exoplanets detected over the past three decades has created a need for fast, reliable methods to study the long-term survival of planetary systems. Here, we investigate the challenging problem of the stability of compact three-planet systems, in which resonant and chaotic processes are intrinsically linked. Four completely different chaos indicators are tested on a data...
Observations with the TESS and Kepler have revealed that practically all close-in sub-Neptunes form in mean-motion resonant chains, most of which unravel on timescales of 100 Myr. Using a series of N-body integrations, we study how planetary collisions resulting from the destabilization of resonant chains produce the distribution of orbital periods observed among mature systems, focusing on...
In nearly integrable Hamiltonian systems with n degrees of freedom, KAM theory guarantees, under suitable conditions, the existence of invariant tori of maximal dimension n , foliated by quasiperiodic orbits. In addition to these maximal tori, resonant tori of lower dimension p < n may also exist. These lower-dimensional tori play an important role in the study of extrasolar planetary systems....
Many transit-detected extrasolar systems harbor complex dynamical evolution governed by two-body resonances and/or chains of resonances. I will discuss how formation and dynamical studies can be useful to constrain the orbital parameters of these systems, which generally suffer from significant observational uncertainties. More precisely, I will show how i) periodic orbits can serve as...
Planetary migration models predict multiple planets captured into a chain of mean-motion resonances during the disk phase. Over a dozen systems have been observed in these configurations, nearly all close-in planets, with a lack of resonant chains for planets with orbital periods larger than ∼300 days. Dynamical studies often overlook the fact that stars do not evolve in isolation. In this...
Multi-planetary systems reveal diverse dynamical histories. Stellar obliquity is a key diagnostic of these histories, linking past dynamical interactions to migration pathways (e.g., quiescent disc vs. violent high-eccentricity). To measure the remaining dynamical violence of planetary systems, we introduce an obliquity-based NAMD (Normalized Angular Momentum Deficit), improving on the...
Young planetary systems are subjected to different dynamical effects that can influence their orbital structure over time. In systems with more than one planet, other planets can internally influence each other, e.g. via planet-planet scattering. In addition, external perturbing effects also need to be taken into account, as stars do not form by themselves but together with other stars in...
Extrasolar planetary systems commonly exhibit planets on eccentric orbits, with many systems located near or within mean-motion resonances, showcasing a wide diversity of orbital architectures. Such complex systems challenge traditional secular theories, which are limited to first-order approximations in planetary masses or rely on expansions in orbital elements—eccentricities, inclinations,...
More than a decade ago, several studies were published in order to investigate the nature of the periodic signal in radial velocity data for the 𝞶 Octantis binary system. The most likely explanation is the existence of a planet in a retrograde orbit with respect to the binary [1]. The ratio of the orbital periods between the potential planet and the binary is close to 5/2, so the possibility...
We consider the dynamic evolution of the compact four-planetary system K2-72. Star K2-72 is an M-type dwarf. The system contains three Earth-like planets and one super-Earth. We searched for low-order resonances within the uncertainty of determining the periods of the planets. We considered a few scenarios for the evolution of the K2-72 system over 100 Myr using the Posidonius software, which...
Evolution models of planetary systems find that resonant chains of planets often arise from their formation within protoplanetary disks. However, the occurrence of observed resonant chains, such as the notable TRAPPIST-1 system, is relatively low. This suggests that most of these chains become destabilized after the dissipation of the protoplanetary disk. Stellar tides, particularly the...
The orbital eccentricities of exoplanets quantify their current dynamical states and encode information about the predominant processes in their dynamical histories (e.g., the role of giant impacts vs. photoevaporation and core-powered mass loss in sculpting a system's dynamical state). Recent studies have demonstrated a relationship between orbital eccentricity and planet radius, showing...
