Effects of pebble accretion on the growth and composition of planetesimals in the inner Solar System

Abstract

Recent work has shown that aside from the classical view of collisions by increasingly massive planetesimals, the accretion of mm- to m-sized 'pebbles' can also reproduce the mass-orbit distribution of the terrestrial planets. Here, we perform N-body simulations to study the effects of pebble accretion onto growing planetesimals of different diameters located in the inner Solar System. The simulations are run to occur during the lifetime of the gas disc while also simultaneously taking Jupiter's growth into account. We find that pebble accretion can increase the mass in the solid disc by at least a few times its initial mass with reasonable assumptions that pebbles fragment to smaller-sized grains at the snow line and that gas-disc-induced orbital migration effects are in force. Such a large contribution in mass by pebbles would seem to imply that the isotopic composition of the inner Solar System should be similar to the pebble source (i.e. outer Solar System). This implication appears to violate the observed nucleosynthetic isotopic dichotomy of the sampled Solar System. Thus, pebble accretion played little or no role in terrestrial planet formation.

18 pages, 11 figures, accepted for publication in MNRAS

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Cited by in corpus (8)

• Anatomy of rocky planets formed by rapid pebble accretion I. How icy pebbles determine the core fraction and FeO contents
• A race against the clock: Constraining the timing of cometary bombardment relative to Earth's growth
• Terrestrial planet formation during giant planet formation and giant planet migration I: The first 5 million years
• The effect of collisional erosion on the composition of Earth-analog planets in Grand Tack models: Implications for the formation of the Earth
• The Effect of Accretion Rate and Composition on the Structure of Ice-rich Super-Earths
• Spatial distribution of isotopes and compositional mixing in the inner protoplanetary disk
• Diversity of Exoplanets
• Forming Earth-like and Low-Mass Rocky Exoplanets Through Pebble and Planetesimal Accretion