How disc initial conditions sculpt the atmospheric composition of giant planets

Fuente: arXiv
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Autori principali: Franco, Angie Daniela Guzmán, Savvidou, Sofia, Bitsch, Bertram
Natura: Preprint
Pubblicazione: 2026
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author Franco, Angie Daniela Guzmán
Savvidou, Sofia
Bitsch, Bertram
author_facet Franco, Angie Daniela Guzmán
Savvidou, Sofia
Bitsch, Bertram
contents Past studies have revealed the dependency of the disc parameters (mass, radius, viscosity, grain fragmentation velocity, dust-to-gas ratio) on the formation of giant planets, where more massive discs seem beneficial for giant planet formation. It is unclear how the different disc properties influence the composition of forming giant planets. The idea that the atmospheric abundances can trace directly the formation location of planets is put into question, due to the chemical evolution of the disc, caused by inward drifting and evaporating pebbles. This complicates the idea of a relation between atmospheric abundances and planet formation locations. We use planet formation simulations that include the effects of pebble drift and evaporation and investigate how the different disc parameters influence the atmospheric composition of giant planets. We focus on the atmospheric C/O, C/H, O/H and S/H ratios allowing us to probe tracers for volatiles and refractories and thus different accretion pathways of giant planets. We find that most of the disc parameters have only a limited influence on the atmospheric abundances of gas giants, except for the dust-to-gas ratio, where a larger value results in higher atmospheric abundances. However the atmospheric abundances are determined by the planetary formation location, even in the pebble drift and evaporation scenario. Our study suggests that volatile-rich giant exoplanets predominantly form in the inner disc regions, where they can accrete large fractions of vapour-enhanced gas. Our study shows that simulations that try to trace the origin of giant planets via their atmospheric abundances do not have to probe all disc parameters, as long as the disc parameters allow the formation of giant planets. Our study thus suggests that the diversity of observed planetary compositions is a direct consequence of their formation location and migration history.
format Preprint
id arxiv_https___arxiv_org_abs_2601_10285
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle How disc initial conditions sculpt the atmospheric composition of giant planets
Franco, Angie Daniela Guzmán
Savvidou, Sofia
Bitsch, Bertram
Earth and Planetary Astrophysics
Past studies have revealed the dependency of the disc parameters (mass, radius, viscosity, grain fragmentation velocity, dust-to-gas ratio) on the formation of giant planets, where more massive discs seem beneficial for giant planet formation. It is unclear how the different disc properties influence the composition of forming giant planets. The idea that the atmospheric abundances can trace directly the formation location of planets is put into question, due to the chemical evolution of the disc, caused by inward drifting and evaporating pebbles. This complicates the idea of a relation between atmospheric abundances and planet formation locations. We use planet formation simulations that include the effects of pebble drift and evaporation and investigate how the different disc parameters influence the atmospheric composition of giant planets. We focus on the atmospheric C/O, C/H, O/H and S/H ratios allowing us to probe tracers for volatiles and refractories and thus different accretion pathways of giant planets. We find that most of the disc parameters have only a limited influence on the atmospheric abundances of gas giants, except for the dust-to-gas ratio, where a larger value results in higher atmospheric abundances. However the atmospheric abundances are determined by the planetary formation location, even in the pebble drift and evaporation scenario. Our study suggests that volatile-rich giant exoplanets predominantly form in the inner disc regions, where they can accrete large fractions of vapour-enhanced gas. Our study shows that simulations that try to trace the origin of giant planets via their atmospheric abundances do not have to probe all disc parameters, as long as the disc parameters allow the formation of giant planets. Our study thus suggests that the diversity of observed planetary compositions is a direct consequence of their formation location and migration history.
title How disc initial conditions sculpt the atmospheric composition of giant planets
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2601.10285