Can the giant planets of the Solar System form via pebble accretion in a smooth protoplanetary disc?
Abstract
Context. Prevailing N-body planet formation models typically start with lunar-mass embryos and show a general trend of rapid migration of massive planetary cores to the inner Solar System in the absence of a migration trap. This setup cannot capture the evolution from a planetesimal to embryo, which is crucial to the final architecture of the system.
Aims: We aim to model planet formation with planet migration starting with planetesimals of ~10−6−10−4 M⊕ and reproduce the giant planets of the Solar System.
Methods: We simulated a population of 1000-5000 planetesimals in a smooth protoplanetary disc, which was evolved under the effects of their mutual gravity, pebble accretion, gas accretion, and planet migration, employing the parallelized N-body code SyMBAp.
Results: We find that the dynamical interactions among growing planetesimals are vigorous and can halt pebble accretion for excited bodies. While a set of results without planet migration produces one to two gas giants and one to two ice giants beyond 6 au, massive planetary cores readily move to the inner Solar System once planet migration is in effect.
Conclusions: Dynamical heating is important in a planetesimal disc and the reduced pebble encounter time should be considered in similar models. Planet migration remains a challenge to form cold giant planets in a smooth protoplanetary disc, which suggests an alternative mechanism is required to stop them at wide orbits.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- March 2024
- DOI:
- arXiv:
- arXiv:2401.05036
- Bibcode:
- 2024A&A...683A.204L
- Keywords:
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- methods: numerical;
- planets and satellites: formation;
- planet-disk interactions;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 17 pages, 14 figures, replaced with published version on A&