Interaction Cross Sections and Survival Rates for Proposed Solar System Member Planet Nine

Abstract

Motivated by the report of a possible new planetary member of the Solar System, this work calculates cross sections for interactions between passing stars and this proposed Planet Nine. Evidence for the new planet is provided by the orbital alignment of Kuiper Belt objects, and other Solar System properties, which suggest a Neptune-mass object on an eccentric orbit with semimajor axis $a_9\approx 400-1500$ AU. With such a wide orbit, Planet Nine has a large interaction cross section, and is susceptible to disruption by passing stars. Using a large ensemble of numerical simulations (several million), and Monte Carlo sampling, we calculate the cross sections for different classes of orbit-altering events: [A] scattering the planet into its proposed orbit from a smaller orbit, [B] ejecting it from the Solar System from its current orbit, [C] capturing the planet from another system, and [D] capturing a free-floating planet. Results are presented for a range of orbital elements with planetary mass $m_9=10M_{earth}$. Removing Planet Nine from the Solar System is the most likely outcome. Specifically, we obtain ejection cross sections ${\sigma }_{int}\sim 5\times 10^6$ AU${}^2$ ($5\times 10^4$ AU${}^2$) for environments corresponding to the birth cluster (field). With these cross sections, Planet Nine is likely to be ejected if the Sun resides within its birth cluster longer than $\Delta t\gtrsim 100$ Myr. The probability of ejecting Planet Nine due to passing field stars is $\lesssim 3\%$ over the age of the Sun. Probabilities for producing the inferred Planet Nine orbit are low $(\lesssim 5\%)$.

16 pages, 3 figures Accepted for publication in ApJL

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Cited by in corpus (48)

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• Constraints on Planet Nine's Orbit and Sky Position within a Framework of Mean Motion Resonances
• Dynamics of Planetary Systems Within Star Clusters: Aspects of the Solar System's Early Evolution
• Fly-by encounters between two planetary systems I: solar system analogues
• Consequences of a Distant Massive Planet on the Large Semi-major Axis Trans-Neptunian Objects
• The fates of Solar system analogues with one additional distant planet
• Identifying Interstellar Objects Trapped in the Solar System through Their Orbital Parameters
• The rate of stellar encounters along a migrating orbit of the Sun
• The Hunt for Planet Nine: Atmosphere, Spectra, Evolution, and Detectability
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• Making Planet Nine: A Scattered Giant in the Outer Solar System
• Making Planet Nine: Pebble Accretion at 250--750 AU in a Gravitationally Unstable Ring
• Was Planet 9 captured in the Sun's natal star-forming region?
• Mildly-Hierarchical triple dynamics and applications to the outer solar system
• Evaluating the Dynamical Stability of Outer Solar System Objects in the Presence of Planet Nine
• The Secular Dynamics of TNOs and Planet Nine Interactions
• Preliminary constraints on the location of the recently hypothesized new planet of the Solar System from planetary orbital dynamics
• Dynamical impact of the Planet Nine scenario: N-body experiments
• Periodic repeating fast radio bursts: interaction between a magnetized neutron star and its planet in an eccentric orbit
• Finding Planet Nine: a Monte Carlo approach
• The Generation of the Distant Kuiper Belt by Planet Nine from an Initially Broad Perihelion Distribution
• Finding Planet Nine: apsidal anti-alignment Monte Carlo results
• Chaotic Dynamics of Trans-Neptunian Objects Perturbed by Planet Nine
• Stellar Flybys Interrupting Planet-Planet Scattering Generates Oort Planets
• Simulations of the Solar System's Early Dynamical Evolution with a Self-Gravitating Planetesimal Disk
• Circularizing Planet Nine through dynamical friction with an extended, cold planetesimal belt
• Dark Exoplanets
• Binary stripping as a plausible origin of correlated pairs of extreme trans-Neptunian objects
• The Case for an Early Solar Binary Companion
• H-Atmospheres of Icy Super-Earths Formed in situ in the Outer Solar System: An Application to a Possible Planet Nine
• Tilting Uranus via Secular Spin-Orbit Resonance with Planet 9
• Dynamics of the clumps partially disrupted from a planet around a neutron star
• On the origin of extreme trans-Neptunian objects within Modified Newtonian Dynamics
• The New Astronomical Frontier of Interstellar Objects
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• The Influence of Planet 9 on the Orbits of Distant TNOs: The Case for a Low Perihelion Planet
• Very-wide-orbit planets from dynamical instabilities during the stellar birth cluster phase
• A new approach to distant solar system object detection in large survey data sets
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• Secular Eccentricity Oscillations in Axisymmetric Disks of Eccentric Orbits
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• The Great Planetary Heist: Theft and capture in star-forming regions
• Distant TNO Inclinations as a Constraint on Primordial Cluster Perturbations in the Presence of Planet Nine