Interstellar Meteors from Tidal Disruption of Rocky Planets on Eccentric Orbits Around M Dwarfs

Fuente: arXiv
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Main Authors: Loeb, Abraham, MacLeod, Morgan
Format: Preprint
Published: 2023
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author Loeb, Abraham
MacLeod, Morgan
author_facet Loeb, Abraham
MacLeod, Morgan
contents Low-mass stars appear to frequently host planetary systems. When these rocky planets develop high eccentricities as a result of secular torques or dynamical scatterings, they occasionally pass close to the host star. In these close passages, planets can be tidally disrupted, and sheared into bound and unbound debris tails. To suffer such a disruption the stellar density must by higher than the planetary density. This condition is met for the most common star and planet systems, M-dwarf stars hosting rocky planets. We describe the dynamics of a tidal disruption, and estimate the typical velocities of unbound ejecta. We simulate the gas dynamics of a planetary tidal disruption, and show that disruptions preserve the layered structure of a rocky body, with the outermost layers flung into interstellar space with the highest velocities. We compare these properties to that of the candidate interstellar meteoroid CNEOS-2014-01-08 (IM1). IM1's approximately 60~km~s$^{-1}$ excess speed relative to the local standard of rest is naturally reproduced by the unbound debris of the disruption of an Earth-like planet around an M-dwarf star. We suggest that such an encounter might explain the interstellar kinematics of IM1, and its unusual composition, especially if it originated in the fastest-expelled crust of a differentiated rocky planet. Finally, we estimate that the disruption of $\sim 10M_\oplus$ reservoirs of rocky planets per M-dwarf are needed to reproduce the inferred rate of IM1-like objects.
format Preprint
id arxiv_https___arxiv_org_abs_2310_09399
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Interstellar Meteors from Tidal Disruption of Rocky Planets on Eccentric Orbits Around M Dwarfs
Loeb, Abraham
MacLeod, Morgan
Earth and Planetary Astrophysics
Astrophysics of Galaxies
Solar and Stellar Astrophysics
Low-mass stars appear to frequently host planetary systems. When these rocky planets develop high eccentricities as a result of secular torques or dynamical scatterings, they occasionally pass close to the host star. In these close passages, planets can be tidally disrupted, and sheared into bound and unbound debris tails. To suffer such a disruption the stellar density must by higher than the planetary density. This condition is met for the most common star and planet systems, M-dwarf stars hosting rocky planets. We describe the dynamics of a tidal disruption, and estimate the typical velocities of unbound ejecta. We simulate the gas dynamics of a planetary tidal disruption, and show that disruptions preserve the layered structure of a rocky body, with the outermost layers flung into interstellar space with the highest velocities. We compare these properties to that of the candidate interstellar meteoroid CNEOS-2014-01-08 (IM1). IM1's approximately 60~km~s$^{-1}$ excess speed relative to the local standard of rest is naturally reproduced by the unbound debris of the disruption of an Earth-like planet around an M-dwarf star. We suggest that such an encounter might explain the interstellar kinematics of IM1, and its unusual composition, especially if it originated in the fastest-expelled crust of a differentiated rocky planet. Finally, we estimate that the disruption of $\sim 10M_\oplus$ reservoirs of rocky planets per M-dwarf are needed to reproduce the inferred rate of IM1-like objects.
title Interstellar Meteors from Tidal Disruption of Rocky Planets on Eccentric Orbits Around M Dwarfs
topic Earth and Planetary Astrophysics
Astrophysics of Galaxies
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2310.09399