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Unraveling the origin of giant exoplanets Observational implications of convective mixing

delete2025-05-23
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PRE
AI
H
Henrik Knierim *
R
Ravit Helled
DOI:10.1051/0004-6361/202554506delete
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Abstract

Abstract

En 中文
The connection between the atmospheric composition of giant planets and their origin remains elusive. In this study, we explore how convective mixing can link the primordial planetary state to its atmospheric composition. We simulate the long-term evolution of gas giants with masses between 0.3 and 3 M-J, considering various composition profiles and primordial entropies (assuming no entropy-mass dependence). Our results show that when convective mixing is considered, the atmospheric metallicity increases with time and that this time evolution encodes information about the primordial planetary structure. Additionally, the degree of compositional mixing affects the planetary radius, altering its evolution in a measurable way. By applying mock observations, we demonstrate that combining radius and atmospheric composition can help to constrain the planetary formation history. Young systems emerge as prime targets for such characterization, with lower-mass gas giants (approaching Saturn's mass) being particularly susceptible to mixing-induced changes. Our findings highlight convective mixing as a key mechanism for probing the primordial state of giant planets, offering new constraints on formation models and demonstrating that the conditions inside giant planets shortly after their formation are not necessarily erased over billions of years and can leave a lasting imprint on their evolution.
Keywords:
convection
planets and satellites: atmospheres
planets and satellites: composition
planets and satellites: gaseous planets
planets and satellites: interiors
planets and satellites: physical evolution

Journal

Astronomy and Astrophysics cover
Astronomy and Astrophysics
IF:
5.8
Papers:
5.0W
Citations:
18.3W

Organization

U
Univ Zurich
Scholars:
1.9K
Papers: 875
Citations: 447
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