magma ocean
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2022 ◽  
Vol 49 (2) ◽  
Author(s):  
Chloé Michaut ◽  
Jerome A. Neufeld
Keyword(s):  

Icarus ◽  
2022 ◽  
Vol 371 ◽  
pp. 114699
Author(s):  
Giuliano Kraettli ◽  
Max W. Schmidt ◽  
Christian Liebske

2021 ◽  
Author(s):  
Surya Pachhai ◽  
Mingming Li ◽  
Michael S. Thorne ◽  
Jan Dettmer ◽  
Hrvoje Tkalčić

2021 ◽  
Vol 2 (6) ◽  
pp. 230
Author(s):  
Noah Jäggi ◽  
Diana Gamborino ◽  
Dan J. Bower ◽  
Paolo A. Sossi ◽  
Aaron S. Wolf ◽  
...  

Abstract MESSENGER observations suggest a magma ocean formed on proto-Mercury, during which evaporation of metals and outgassing of C- and H-bearing volatiles produced an early atmosphere. Atmospheric escape subsequently occurred by plasma heating, photoevaporation, Jeans escape, and photoionization. To quantify atmospheric loss, we combine constraints on the lifetime of surficial melt, melt composition, and atmospheric composition. Consideration of two initial Mercury sizes and four magma ocean compositions determines the atmospheric speciation at a given surface temperature. A coupled interior–atmosphere model determines the cooling rate and therefore the lifetime of surficial melt. Combining the melt lifetime and escape flux calculations provides estimates for the total mass loss from early Mercury. Loss rates by Jeans escape are negligible. Plasma heating and photoionization are limited by homopause diffusion rates of ∼106 kg s−1. Loss by photoevaporation depends on the timing of Mercury formation and assumed heating efficiency and ranges from ∼106.6 to ∼109.6 kg s−1. The material for photoevaporation is sourced from below the homopause and is therefore energy limited rather than diffusion limited. The timescale for efficient interior–atmosphere chemical exchange is less than 10,000 yr. Therefore, escape processes only account for an equivalent loss of less than 2.3 km of crust (0.3% of Mercury’s mass). Accordingly, ≤0.02% of the total mass of H2O and Na is lost. Therefore, cumulative loss cannot significantly modify Mercury’s bulk mantle composition during the magma ocean stage. Mercury’s high core:mantle ratio and volatile-rich surface may instead reflect chemical variations in its building blocks resulting from its solar-proximal accretion environment.


2021 ◽  
Vol 922 (1) ◽  
pp. L4
Author(s):  
Caroline Dorn ◽  
Tim Lichtenberg

Abstract We demonstrate that the deep volatile storage capacity of magma oceans has significant implications for the bulk composition, interior, and climate state inferred from exoplanet mass and radius data. Experimental petrology provides the fundamental properties of the ability of water and melt to mix. So far, these data have been largely neglected for exoplanet mass–radius modeling. Here we present an advanced interior model for water-rich rocky exoplanets. The new model allows us to test the effects of rock melting and the redistribution of water between magma ocean and atmosphere on calculated planet radii. Models with and without rock melting and water partitioning lead to deviations in planet radius of up to 16% for a fixed bulk composition and planet mass. This is within the current accuracy limits for individual systems and statistically testable on a population level. Unrecognized mantle melting and volatile redistribution in retrievals may thus underestimate the inferred planetary bulk water content by up to 1 order of magnitude.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haruka Sakuraba ◽  
Hiroyuki Kurokawa ◽  
Hidenori Genda ◽  
Kenji Ohta

AbstractEarth’s surface environment is largely influenced by its budget of major volatile elements: carbon (C), nitrogen (N), and hydrogen (H). Although the volatiles on Earth are thought to have been delivered by chondritic materials, the elemental composition of the bulk silicate Earth (BSE) shows depletion in the order of N, C, and H. Previous studies have concluded that non-chondritic materials are needed for this depletion pattern. Here, we model the evolution of the volatile abundances in the atmosphere, oceans, crust, mantle, and core through the accretion history by considering elemental partitioning and impact erosion. We show that the BSE depletion pattern can be reproduced from continuous accretion of chondritic bodies by the partitioning of C into the core and H storage in the magma ocean in the main accretion stage and atmospheric erosion of N in the late accretion stage. This scenario requires a relatively oxidized magma ocean ($$\log _{10} f_{{\mathrm{O}}_2}$$ log 10 f O 2 $$\gtrsim$$ ≳ $${\mathrm{IW}}$$ IW $$-2$$ - 2 , where $$f_{{\mathrm{O}}_2}$$ f O 2 is the oxygen fugacity, $$\mathrm{IW}$$ IW is $$\log _{10} f_{{\mathrm{O}}_2}^{\mathrm{IW}}$$ log 10 f O 2 IW , and $$f_{{\mathrm{O}}_2}^{\mathrm{IW}}$$ f O 2 IW is $$f_{{\mathrm{O}}_2}$$ f O 2 at the iron-wüstite buffer), the dominance of small impactors in the late accretion, and the storage of H and C in oceanic water and carbonate rocks in the late accretion stage, all of which are naturally expected from the formation of an Earth-sized planet in the habitable zone.


2021 ◽  
Vol 7 (41) ◽  
Author(s):  
Natalia V. Solomatova ◽  
Razvan Caracas
Keyword(s):  

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