Irregular moons possibly injected from the outer solar system by a stellar flyby

Abstract

The irregular moons orbit the giant planets on distant, inclined, and eccentric trajectories, in sharp contrast with the coplanar and quasicircular orbits of the regular moons. The origin of these irregular moons is still an open question, but these moons have a lot in common with the objects beyond Neptune (trans-Neptunian objects -- TNOs), suggestive of a common origin. Here, we show that the close flyby of a star may be the connecting element. A stellar flyby can simultaneously reproduce the complex TNO dynamics quantitatively while explaining the origin of the irregular moons and the colour distributions of both populations. This flyby would have catapulted 7.2% of the original TNO population into the region of the planets, many on retrograde orbits. Most injected TNOs would have been subsequently ejected from the solar system (85%). However, a considerable fraction would have had the potential to be captured by the planets. The exclusively distant origin of the injected TNOs may also explain the lack of very red irregular moons.

5 pages, 4 figures

References in corpus (22)

• LSST: from Science Drivers to Reference Design and Anticipated Data Products
• IAS15: A fast, adaptive, high-order integrator for gravitational dynamics, accurate to machine precision over a billion orbits
• Observations of Protoplanetary Disk Structures
• Irregular Satellites of the Planets: Products of Capture in the Early Solar System
• Stellar encounters as the origin of distant solar system objects in highly eccentric orbits
• The three-body problem
• The evolution of dust-disk sizes from a homogeneous analysis of 1-10 Myr-old stars
• The albedo-color diversity of transneptunian objects
• The Effects of a Stellar Encounter on a Planetesimal Disk
• Capture of Irregular Satellites at Jupiter
• The GENGA Code: Gravitational Encounters in N-body simulations with GPU Acceleration
• Stability of prograde and retrograde planets in circular binary systems
• Solution to the debris disc mass problem: planetesimals are born small?
• Col-OSSOS: The Colours of the Outer Solar System Origins Survey
• Outer solar system possibly shaped by a stellar fly-by
• Mass of the Kuiper Belt
• Disc-mass distribution in star-disc encounters
• Colors and Shapes of the Irregular Planetary Satellites
• The secular evolution of the Kuiper belt after a close stellar encounter
• Can comets deliver prebiotic molecules to rocky exoplanets?
• JWST Spectrophotometry of the Small Satellites of Uranus and Neptune
• Colors of Irregular Satellites of Saturn with DECam

Cited by in corpus (1)

• Oort Cloud Ecology. III. The Sun left the parent star cluster shortly after the giant planets formed