Chaotic diffusion of asteroids in the exterior 1:2 mean motion resonance with Mars. (arXiv:2207.14047v2 [astro-ph.EP] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Christou_A/0/1/0/all/0/1">Apostolos A. Christou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dermott_S/0/1/0/all/0/1">Stanley F. Dermott</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_D/0/1/0/all/0/1">Dan Li</a>
The inner asteroid belt between 2.1 and 2.5 au is of particular dynamical
significance because it is the dominant source of both chondritic meteorites
and near-Earth asteroids. This inner belt is bounded by an eccentricity-type
secular resonance and by the 1:3 mean motion resonance with Jupiter. Unless
asteroid perihelia are low enough to allow scattering by Mars, escape requires
transport to one of the bounding resonances. In addition Yarkovsky forces are
generally ineffective in changing either the eccentricity and/or inclination
for asteroids with diameter $gtrsim$30 km. Thus, large asteroids with
pericentres far from Mars may only escape from the inner belt through large
changes in their eccentricities. In this paper we study chaotic diffusion of
orbits near the 1:2 mean motion resonance with Mars in a systematic way. We
show that, while chaotic orbital evolution in both resonant and non-resonant
orbits increase the dispersion of the inclinations and eccentricities, it does
not significantly change their mean values. We show further that, while the
dispersive growth is greatest for resonant orbits, at high $e$ the resonance
acts to mitigate asteroid scattering by Mars – making the asteroid lifetime in
the belt longer than it would have been for a non-resonant orbit. For asteroids
of all sizes in both resonant and non-resonant orbits, the changes in
eccentricity needed to account for the observations cannot be achieved by
gravitational forces alone. The role of resonant trapping in protecting
asteroids from encounters with Mars is also analysed.
The inner asteroid belt between 2.1 and 2.5 au is of particular dynamical
significance because it is the dominant source of both chondritic meteorites
and near-Earth asteroids. This inner belt is bounded by an eccentricity-type
secular resonance and by the 1:3 mean motion resonance with Jupiter. Unless
asteroid perihelia are low enough to allow scattering by Mars, escape requires
transport to one of the bounding resonances. In addition Yarkovsky forces are
generally ineffective in changing either the eccentricity and/or inclination
for asteroids with diameter $gtrsim$30 km. Thus, large asteroids with
pericentres far from Mars may only escape from the inner belt through large
changes in their eccentricities. In this paper we study chaotic diffusion of
orbits near the 1:2 mean motion resonance with Mars in a systematic way. We
show that, while chaotic orbital evolution in both resonant and non-resonant
orbits increase the dispersion of the inclinations and eccentricities, it does
not significantly change their mean values. We show further that, while the
dispersive growth is greatest for resonant orbits, at high $e$ the resonance
acts to mitigate asteroid scattering by Mars – making the asteroid lifetime in
the belt longer than it would have been for a non-resonant orbit. For asteroids
of all sizes in both resonant and non-resonant orbits, the changes in
eccentricity needed to account for the observations cannot be achieved by
gravitational forces alone. The role of resonant trapping in protecting
asteroids from encounters with Mars is also analysed.
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