The Origin and Evolution of Saturn: A Post-Cassini Perspective

Fuente: arXiv
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Main Authors: Atreya, Sushil K., Crida, Aurélien, Guillot, Tristan, Li, Cheng, Lunine, Jonathan I., Madhusudhan, Nikku, Mousis, Olivier, Wong, Michael H.
Format: Preprint
Published: 2022
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author Atreya, Sushil K.
Crida, Aurélien
Guillot, Tristan
Li, Cheng
Lunine, Jonathan I.
Madhusudhan, Nikku
Mousis, Olivier
Wong, Michael H.
author_facet Atreya, Sushil K.
Crida, Aurélien
Guillot, Tristan
Li, Cheng
Lunine, Jonathan I.
Madhusudhan, Nikku
Mousis, Olivier
Wong, Michael H.
contents The Saturn System has been studied in detail by the Cassini-Huygens Mission. A major thrust of those investigations has been to understand how Saturn formed and evolved and to place Saturn in the context of other gas giants and planetary systems in general. Two models have been proposed for the formation of the giant planets,the core accretion model and the disk instability model. The heavy element enrichment, core size, and internal structure of Saturn, compared to Jupiter strongly favor the core accretion model as for Jupiter. Two features of the core accretion model that are distinct from the disk instability model are the growth of a core with a mass several times that of the Earth, followed by runaway collapse of gas onto the core once a mass threshold is reached. The heavy element core grows slowly over millions of years through accretion of cm-m sized pebbles, even larger bodies, and moon sized embryos in the gaseous disk. The abundance pattern of heavy elements is thus a key constraint on formation models. C, N, S, and P at Saturn are presently known to varying degree of uncertainty. The He to H ratio in the atmosphere is crucial for understanding heat balance, interior processes, and planetary evolution, but present values at Saturn range from low to high, allowing for a wide range of possibilities. While the very low values are favored to explain excess luminosity, high values might indicate presence of layered convection in the interior, resulting in slow cooling. Additional insight into Saturn's formation comes from the unique data on the rings from Cassini's Grand Finale orbits. While the solar system is the only analog for the extra solar systems, detection of the alkali metals and water in giant exoplanets is useful for understanding the formation and evolution of Saturn, where such data are presently lacking.
format Preprint
id arxiv_https___arxiv_org_abs_2205_06914
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle The Origin and Evolution of Saturn: A Post-Cassini Perspective
Atreya, Sushil K.
Crida, Aurélien
Guillot, Tristan
Li, Cheng
Lunine, Jonathan I.
Madhusudhan, Nikku
Mousis, Olivier
Wong, Michael H.
Earth and Planetary Astrophysics
The Saturn System has been studied in detail by the Cassini-Huygens Mission. A major thrust of those investigations has been to understand how Saturn formed and evolved and to place Saturn in the context of other gas giants and planetary systems in general. Two models have been proposed for the formation of the giant planets,the core accretion model and the disk instability model. The heavy element enrichment, core size, and internal structure of Saturn, compared to Jupiter strongly favor the core accretion model as for Jupiter. Two features of the core accretion model that are distinct from the disk instability model are the growth of a core with a mass several times that of the Earth, followed by runaway collapse of gas onto the core once a mass threshold is reached. The heavy element core grows slowly over millions of years through accretion of cm-m sized pebbles, even larger bodies, and moon sized embryos in the gaseous disk. The abundance pattern of heavy elements is thus a key constraint on formation models. C, N, S, and P at Saturn are presently known to varying degree of uncertainty. The He to H ratio in the atmosphere is crucial for understanding heat balance, interior processes, and planetary evolution, but present values at Saturn range from low to high, allowing for a wide range of possibilities. While the very low values are favored to explain excess luminosity, high values might indicate presence of layered convection in the interior, resulting in slow cooling. Additional insight into Saturn's formation comes from the unique data on the rings from Cassini's Grand Finale orbits. While the solar system is the only analog for the extra solar systems, detection of the alkali metals and water in giant exoplanets is useful for understanding the formation and evolution of Saturn, where such data are presently lacking.
title The Origin and Evolution of Saturn: A Post-Cassini Perspective
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2205.06914