Trajectory of the stellar flyby that shaped the outer solar system

Fuente: arXiv
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Main Authors: Pfalzner, Susanne, Govind, Amith, Zwart, Simon Portegies
Format: Preprint
Published: 2024
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author Pfalzner, Susanne
Govind, Amith
Zwart, Simon Portegies
author_facet Pfalzner, Susanne
Govind, Amith
Zwart, Simon Portegies
contents Unlike the Solar System planets, thousands of smaller bodies beyond Neptune orbit the Sun on eccentric ($e >$ 0.1) and ($i>$ 3$^\circ$) orbits. While migration of the giant planets during the early stages of Solar System evolution can induce substantial scattering of trans-Neptunian objects (TNO), this process cannot account for the small number of distant TNOs ($r_p >$ 60 au) outside the planets' reach. The alternative scenario of the close flyby of another star can instead produce all these TNO features simultaneously, but the possible parameter space for such an encounter is vast. Here, we compare observed TNO properties with thousands of flyby simulations to determine the specific properties of a flyby that reproduces all the different dynamical TNO populations, their location and their relative abundance and find that a 0.8$^{+0.1}_{-0.1}$ $M_{\odot}$ star passing at a distance of $ r_p =$ 110 $\mathbf{\pm}$ 10 au, inclined by $i$ = 70$^\circ$ $^{+5}_{-10}$ gives a near-perfect match. This flyby also replicates the retrograde TNO population, which has proved difficult to explain. Such a flyby is reasonably frequent; at least 140 million solar-type stars in the Milky Way are likely to have experienced a similar one. In light of these results, we predict that the upcoming Vera Rubin telescope will reveal that distant and retrograde TNOs are relatively common.
format Preprint
id arxiv_https___arxiv_org_abs_2409_03342
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Trajectory of the stellar flyby that shaped the outer solar system
Pfalzner, Susanne
Govind, Amith
Zwart, Simon Portegies
Earth and Planetary Astrophysics
Astrophysics of Galaxies
Solar and Stellar Astrophysics
Unlike the Solar System planets, thousands of smaller bodies beyond Neptune orbit the Sun on eccentric ($e >$ 0.1) and ($i>$ 3$^\circ$) orbits. While migration of the giant planets during the early stages of Solar System evolution can induce substantial scattering of trans-Neptunian objects (TNO), this process cannot account for the small number of distant TNOs ($r_p >$ 60 au) outside the planets' reach. The alternative scenario of the close flyby of another star can instead produce all these TNO features simultaneously, but the possible parameter space for such an encounter is vast. Here, we compare observed TNO properties with thousands of flyby simulations to determine the specific properties of a flyby that reproduces all the different dynamical TNO populations, their location and their relative abundance and find that a 0.8$^{+0.1}_{-0.1}$ $M_{\odot}$ star passing at a distance of $ r_p =$ 110 $\mathbf{\pm}$ 10 au, inclined by $i$ = 70$^\circ$ $^{+5}_{-10}$ gives a near-perfect match. This flyby also replicates the retrograde TNO population, which has proved difficult to explain. Such a flyby is reasonably frequent; at least 140 million solar-type stars in the Milky Way are likely to have experienced a similar one. In light of these results, we predict that the upcoming Vera Rubin telescope will reveal that distant and retrograde TNOs are relatively common.
title Trajectory of the stellar flyby that shaped the outer solar system
topic Earth and Planetary Astrophysics
Astrophysics of Galaxies
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2409.03342