
arXiv: 2501.13166
Abstract 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 ejected, depending on the initial number in the system. Most ejections occur over ∼108–109 yr. The mean excess velocity of ejected planets lies in the range 2–6 km s−1 relative to the host star, and strongly depends on the semimajor axis of the innermost planet. Regardless of initial location, all planets are equally likely to be ejected. Bound and ejected planets show distinct mass distributions, with bound planets being more massive. Increasing planetary radii reduces the ejection fraction due to higher collision rates. The properties of ejected planets do not strongly depend on initial spacing, though ejection timescales increase with separation. The ejection fraction is also largely insensitive to the distance from the host star used to define unbound status. Comparing our results with observed free-floating planet populations, we conclude that fewer than five Jovian-mass planets need to form per star to match observations—consistent with current constraints from both observations and planet formation models.
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astrophysics - Astrophysics of Galaxies, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astrophysics - Astrophysics of Galaxies, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 0 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Average | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Average | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
