Multiple studies show that planet–planet scattering plays a key role in the dynamical evolution of planetary systems. It can also contribute to the census of free-floating planets. In this work, we run an ensemble of N-body simulations and record the properties of ejected planets. Our simulations sample a wide range of orbital and physical parameters. We find that 40%–80% of planets are...
There is strong evidence from the broad eccentricity distribution of giant exoplanets that dynamical instabilities are ubiquitous. During the ejection of a planet, it may spend time on a wide enough orbit to be subject to external torques, from both passing stars (in particular, for early instabilities while the Sun was in its birth cluster) and the Galactic tidal field (for later dynamical...
The discovery of free-floating planets (FFPs) firmly confirms the fact that during the formation of a planetary system, fully-formed and still-forming planets are scattered out of the system. As planet formation is an inefficient process, meaning that the large majority of the material in a protoplanetary disk is scattered out and does not contribute to the growth of planetary bodies, question...
The role of massive stellar death in the production of free-floating planets remains poorly explored. We model type II supernovae as a rogue planet formation channel through 2.5 million simulations of planetary and stellar companions exposed to homologous mass loss with typical SN II ejecta velocities of 1000–10,000 km/s. Nearly all companions are destabilized, yielding rogue planets with...
Disc instability (DI) remains the leading formation pathway for some of the observed giant planets. In particular, this model can more naturally explain giant planets at large separation, giant planets around M stars, and very young giant planets. However, there are still many open questions regarding this formation mechanism, and the expected population of planets is currently unknown. We...
Abstract: Metallicity correlations and other observed statistics indicate that disc fragmentation due to Gravitational Instability (GI) is the likely origin of massive companions to stars, such as giant planets orbiting M-dwarf stars, Brown Dwarf (BD) companions to FGK stars, and binary stars with separations smaller than about 100 au. In paper I of this series, we showed that disc...
Over the past 25 years, observations have uncovered a large population of free-floating planets (FFPs), whose origins remain debated. Massive FFPs (several Jupiter masses or more) may form via gravitational collapse of molecular clouds, similar to stars. Lower-mass FFPs likely originate in planetary systems and are later ejected through dynamical interactions. We show that disc fragmentation...
Multiplanet systems are expected to form in resonance chains as a consequence of disk-driven migration. We investigate the dynamical evolution of cold Neptune systems initially assembled in resonance chains that later interact with planetesimals leftover from planet formation. We find that planetesimal masses comprising only 1–2% of the total planetary mass are sufficient not only to break the...
The traditional view of planet formation often treats planetary systems as isolated environments. However, dynamical processes are highly stochastic, and the "release" of material—from planetesimals to fully-formed planets—is a common, if not dominant, outcome. Planet-planet scattering, for instance, is a chaotic "release" mechanism that can eject 40-80% of a system's planets, populating the...
