Water versus land on temperate rocky planets

Fuente: arXiv
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Main Authors: Guimond, Claire Marie, Spohn, Tilman, Berdyugina, Svetlana, Byrne, Paul K., Coltice, Nicolas, Glaser, Donald M., Lingam, Manasvi, Lineweaver, Charles H., Cawood, Peter A.
Format: Preprint
Published: 2025
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author Guimond, Claire Marie
Spohn, Tilman
Berdyugina, Svetlana
Byrne, Paul K.
Coltice, Nicolas
Glaser, Donald M.
Lingam, Manasvi
Lineweaver, Charles H.
Cawood, Peter A.
author_facet Guimond, Claire Marie
Spohn, Tilman
Berdyugina, Svetlana
Byrne, Paul K.
Coltice, Nicolas
Glaser, Donald M.
Lingam, Manasvi
Lineweaver, Charles H.
Cawood, Peter A.
contents Water and land surfaces on a planet interact with gases in the atmosphere and with radiation from the star. These interactions define the environments that prevail on the planet, some of which may be more amenable to prebiotic chemistry, some to the evolution of more complex life. This review article covers (i) the physical conditions that determine the ratio of land to sea on a rocky planet, (ii) how this ratio would affect climatic and biologic processes, and (iii) whether future astronomical observations might constrain this ratio on exoplanets. Water can be delivered in multiple ways to a growing rocky planet -- and although we may not agree on the contribution of different mechanism(s) to Earth's bulk water, hydrated building blocks and nebular ingassing could at least in principle supply several oceans' worth. The water that planets sequester over eons in their solid deep mantles is limited by the water concentration at water saturation of nominally anhydrous mantle minerals, likely less than 2000 ppm of the planet mass. Water is cycled between mantle and surface through outgassing and ingassing mechanisms that, while tightly linked to tectonics, do not necessarily require plate tectonics in every case. The actual water/land ratio at a given time emerges from the balance between the volume of surface water on the one hand, and on the other hand, the shape of the planet (its ocean basin volume) that is carved out by dynamic topography, the petrologic evolution of continents, impact cratering, and other surface-sculpting processes. By leveraging the contrast in reflectance properties of water and land surfaces, spatially resolved 2D maps of Earth-as-an-exoplanet have been retrieved from models using real Earth observations, demonstrating that water/land ratios of rocky exoplanets may be determined from data delivered by large-aperture, high-contrast imaging telescopes in the future.
format Preprint
id arxiv_https___arxiv_org_abs_2512_09785
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Water versus land on temperate rocky planets
Guimond, Claire Marie
Spohn, Tilman
Berdyugina, Svetlana
Byrne, Paul K.
Coltice, Nicolas
Glaser, Donald M.
Lingam, Manasvi
Lineweaver, Charles H.
Cawood, Peter A.
Earth and Planetary Astrophysics
Water and land surfaces on a planet interact with gases in the atmosphere and with radiation from the star. These interactions define the environments that prevail on the planet, some of which may be more amenable to prebiotic chemistry, some to the evolution of more complex life. This review article covers (i) the physical conditions that determine the ratio of land to sea on a rocky planet, (ii) how this ratio would affect climatic and biologic processes, and (iii) whether future astronomical observations might constrain this ratio on exoplanets. Water can be delivered in multiple ways to a growing rocky planet -- and although we may not agree on the contribution of different mechanism(s) to Earth's bulk water, hydrated building blocks and nebular ingassing could at least in principle supply several oceans' worth. The water that planets sequester over eons in their solid deep mantles is limited by the water concentration at water saturation of nominally anhydrous mantle minerals, likely less than 2000 ppm of the planet mass. Water is cycled between mantle and surface through outgassing and ingassing mechanisms that, while tightly linked to tectonics, do not necessarily require plate tectonics in every case. The actual water/land ratio at a given time emerges from the balance between the volume of surface water on the one hand, and on the other hand, the shape of the planet (its ocean basin volume) that is carved out by dynamic topography, the petrologic evolution of continents, impact cratering, and other surface-sculpting processes. By leveraging the contrast in reflectance properties of water and land surfaces, spatially resolved 2D maps of Earth-as-an-exoplanet have been retrieved from models using real Earth observations, demonstrating that water/land ratios of rocky exoplanets may be determined from data delivered by large-aperture, high-contrast imaging telescopes in the future.
title Water versus land on temperate rocky planets
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2512.09785