The consequences of planetary migration on the minor bodies of the early Solar System. (arXiv:1902.04591v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Pirani_S/0/1/0/all/0/1">S. Pirani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johansen_A/0/1/0/all/0/1">A. Johansen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bitsch_B/0/1/0/all/0/1">B. Bitsch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mustill_A/0/1/0/all/0/1">A. J. Mustill</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Turrini_D/0/1/0/all/0/1">D. Turrini</a>
Pebble accretion is an efficient mechanism able to build up the core of the
giant planets within the lifetime of the protoplanetary disc gas-phase. The
core grows via this process until the protoplanet reaches its pebble isolation
mass and starts to accrete gas. During the growth, the protoplanet undergoes a
rapid, large-scale, inward migration due to the interactions with the gaseous
protoplanetary disc. In our work, we investigate how this early migration would
have affected the minor body populations in our solar system. In particular, we
focus on the Jupiter Trojans and the Hildas asteroids. We found that a massive
and eccentric Hilda group is captured during the migration from a region
between 5 and 8 au and subsequently depleted during the late instability of the
giant planets. Our simulations also show that inward migration of the giant
planets always produces a Jupiter Trojans’ leading swarm more populated than
the trailing one, with a ratio comparable to the current observed Trojan
asymmetry ratio. The in situ formation of Jupiter, on the other hand, produces
symmetric leading/trailing swarms. The reason for the asymmetry is the relative
drift between the migrating planet and the particles in the coorbital
resonance. The capture happens during the growth of Jupiter’s core and Trojan
asteroids are afterwards carried along during the giant planet’s migration to
their final orbits. The asymmetry and eccentricity of the captured Trojans
correspond well to observations, but their inclinations are near zero and their
total mass is 3-4 orders of magnitude higher than the current population.
Future modelling will be needed to understand whether the dynamical evolution
of the Trojans over billions of years will raise the inclinations and deplete
the masses to observed values.
Pebble accretion is an efficient mechanism able to build up the core of the
giant planets within the lifetime of the protoplanetary disc gas-phase. The
core grows via this process until the protoplanet reaches its pebble isolation
mass and starts to accrete gas. During the growth, the protoplanet undergoes a
rapid, large-scale, inward migration due to the interactions with the gaseous
protoplanetary disc. In our work, we investigate how this early migration would
have affected the minor body populations in our solar system. In particular, we
focus on the Jupiter Trojans and the Hildas asteroids. We found that a massive
and eccentric Hilda group is captured during the migration from a region
between 5 and 8 au and subsequently depleted during the late instability of the
giant planets. Our simulations also show that inward migration of the giant
planets always produces a Jupiter Trojans’ leading swarm more populated than
the trailing one, with a ratio comparable to the current observed Trojan
asymmetry ratio. The in situ formation of Jupiter, on the other hand, produces
symmetric leading/trailing swarms. The reason for the asymmetry is the relative
drift between the migrating planet and the particles in the coorbital
resonance. The capture happens during the growth of Jupiter’s core and Trojan
asteroids are afterwards carried along during the giant planet’s migration to
their final orbits. The asymmetry and eccentricity of the captured Trojans
correspond well to observations, but their inclinations are near zero and their
total mass is 3-4 orders of magnitude higher than the current population.
Future modelling will be needed to understand whether the dynamical evolution
of the Trojans over billions of years will raise the inclinations and deplete
the masses to observed values.
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