Abstract
Solar and extrasolar planets are the subject of numerous studies aiming to
determine their chemical composition and internal structure. In the case of
extrasolar planets, the composition is important as it partly governs their
potential habitability. Moreover, observational determination of chemical
composition of planetary atmospheres are becoming available, especially for
transiting planets. The present works aims at determining the chemical
composition of planets formed in stellar systems of solar chemical composition.
The main objective of this work is to provide valuable theoretical data for
models of planet formation and evolution, and future interpretation of chemical
composition of solar and extrasolar planets. We have developed a model that
computes the composition of ices in planets in different stellar systems with
the use of models of ice and planetary formation. We provide the chemical
composition, ice/rock mass ratio and C:O molar ratio for planets in stellar
systems of solar chemical composition. From an initial homogeneous composition
of the nebula, we produce a wide variety of planetary chemical compositions as
a function of the mass of the disk and distance to the star. The volatile
species incorporated in planets are mainly composed of H2O, CO, CO2, CH3OH, and
NH3. Icy or ocean planets have systematically higher values of molecular
abundances compared to giant and rocky planets. Gas giant planets are depleted
in highly volatile molecules such as CH4, CO, and N2 compared to icy or ocean
planets. The ice/rock mass ratio in icy or ocean and gas giant planets is,
respectively, equal at maximum to 1.01+-0.33 and 0.8+-0.5, and is different
from the usual assumptions made in planet formation models, which suggested
this ratio to be 2-3. The C:O molar ratio in the atmosphere of gas giant
planets is depleted by at least 30% compared to solar value.
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