Low volcanic outgassing rates for a stagnant lid Archean earth with graphite-saturated magmas

Guimond, Claire Marie; Noack, Lena; Ortenzi, Gianluigi; Sohl, F.

doi:10.1016/j.pepi.2021.106788

Cited by 19 publications

(11 citation statements)

References 95 publications

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“…3 and SI Appendix , Fig. S2 ), consistent with observations of Mercury’s graphite-enriched crust ( 64 ). Rocky exoplanets with ultrareduced magma compositions are unlikely to outgas significant quantities of CH 4 due to graphite saturation, although more experiments are needed to confirm reduced magmas’ outgassing compositions.…”

Section: Resultssupporting

confidence: 87%

The case and context for atmospheric methane as an exoplanet biosignature

Thompson

Krissansen‐Totton

Wogan

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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Significance Astronomers will soon begin searching for biosignatures, atmospheric gases or surface features produced by life, on potentially habitable planets. Since methane is the only biosignature that the James Webb Space Telescope could readily detect in terrestrial atmospheres, it is imperative to understand methane biosignatures to contextualize these upcoming observations. We explore the necessary planetary context for methane to be a persuasive biosignature and assess whether, and in what planetary environments, abiotic sources of methane could result in false-positive scenarios. With these results, we provide a tentative framework for assessing methane biosignatures. If life is abundant in the universe, then with the correct planetary context, atmospheric methane may be the first detectable indication of life beyond Earth.

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Section: Resultssupporting

confidence: 87%

The case and context for atmospheric methane as an exoplanet biosignature

Thompson

Krissansen‐Totton

Wogan

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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“…Carbon partitions into melt also depending on the redox state (Holloway et al 1992;Grott et al 2011;Ortenzi et al 2020), whereas partitioning of water into the melt depends mainly on the melt fraction (Katz et al 2003). The melt and outgassing models are described in detail in Noack et al (2017) and Guimond et al (2021).…”

Section: Interior Evolution and Outgassing Modelmentioning

confidence: 99%

Interior heating and outgassing of Proxima Centauri b: Identifying critical parameters

Noack

Kislyakova

Johnstone

et al. 2021

A&A

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Context. Since the discovery of a potentially low-mass exoplanet around our nearest neighbour star Proxima Centauri, several works have investigated the likelihood of a shielding atmosphere and therefore the potential surface habitability of Proxima Cen b. However, outgassing processes are influenced by several different (unknown) factors such as the actual planet mass, mantle and core composition, and different heating mechanisms in the interior. Aims. We aim to identify the critical parameters that influence the mantle and surface evolution of the planet over time, as well as to potentially constrain the time-dependent input of volatiles from mantle into the atmosphere. Methods. To study the coupled star–planet evolution, we analysed the heating produced in the interior of Proxima Cen b due to induction heating, which strongly varies with both depth and latitude. We calculated different rotation evolutionary tracks for Proxima Centauri and investigated the change in its rotation period and magnetic field strength. Unlike the Sun, Proxima Centauri possesses a very strong magnetic field of at least a few hundred Gauss, which was likely even stronger in the past. We applied an interior structure model for varying planet masses (derived from the unknown inclination of observation of the Proxima Centauri system) and iron weight fractions, that is, different core sizes, in the range of observed Fe-Mg variations in the stellar spectrum. We used a mantle convection model to study the thermal evolution and outgassing efficiency of Proxima Cen b. For unknown planetary parameters such as initial conditions, we chose randomly selected values. We took heating in the interior due to variable radioactive heat sources and induction heating into account and compared the heating efficiency to tidal heating. Results. Our results show that induction heating may have been significant in the past, leading to local temperature increases of several hundreds of Kelvin. This early heating leads to an earlier depletion of the interior and volatile outgassing compared to if the planet had not been subject to induction heating. We show that induction heating has an impact comparable to tidal heating when assuming latest estimates on its eccentricity. Furthermore, we find that the planet mass (linked to the planetary orbital inclination) has a first-order influence on the efficiency of outgassing from the interior.

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“…Previous work has focused on how factors such as the mass, bulk composition, tectonic regime, early volatile content, graphite saturation of magmas, and orbital distance of a planet can affect volcanic outgassing and the resultant secondary atmosphere. These past studies have identified several key features of volcanic secondary atmospheres and how they relate to the broader geodynamic state of the planet: planets which are more massive (>2× the mass of Earth, Noack et al, 2017;Dorn et al, 2018), which have graphite saturated magmas (Guimond et al, 2021), or which have a high iron to silicon ratio (Spaargaren et al, 2020) will have lower outgassing rates; stagnant lid planets tend to grow more massive atmospheres than those with plate tectonics (Spaargaren et al, 2020); plate tectonics is not a pre-requisite for a habitable atmosphere (Tosi et al, 2017); and rocky planets which form with thick primary atmospheres are less likely to have long-lived secondary atmospheres (Kite & Barnett, 2020). Ortenzi et al (2020) have also recently investigated the effect of mantle f O 2 on the atmospheres of rocky planets; however, they only model the atmospheric chemistry in terms of H 2 O, CO 2 , CO and H 2 at very high temperatures (around 2000 K).…”

Section: Atmospheric Modification Processesmentioning

confidence: 99%

Growth and evolution of secondary volcanic atmospheres: I. Identifying the geological character of warm rocky planets

Liggins,

Jordan,

Rimmer

et al. 2021

Preprint

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The geology of Earth and super-Earth sized planets will, in many cases, only be observable via their atmospheres. Here, we use the creation of volcanic atmospheres as a key window into planetary geochemistry. We couple volcanic outgassing with atmospheric chemistry models to simulate the growth of C-O-H-S-N atmospheres in thermochemical equilibrium, aiming to establish what information about the planet's mantle f O 2 and bulk silicate H/C ratio can be determined by atmospheric observation. Warm (800 K) volcanic atmospheres develop distinct compositional groups as the mantle f O 2 is varied, which can be identified using sets of (often minor) indicator species: Class O, representing an oxidised mantle and containing SO 2 and sulphur allotropes; Class I, formed by intermediate mantle f O 2 's and containing CO 2 , CH 4 , CO and COS; and Class R, produced by reduced mantles, containing H 2 , NH 3 and CH 4 . These atmospheric classes are largely independent of the bulk silicate H/C ratio. However, the H/C ratio does affect the dominant atmospheric constituent, which can vary between H 2 , H 2 O, CO 2 and CH 4 once the chemical composition has stabilised to a point where it no longer changes substantially with time. This final state is dependent on the mantle f O 2 , the H/C ratio, and time since the onset of volcanism. Superchondritic H/C enrichment to the level of Earth (H/C = 0.99 ± 0.42) and higher can only be inferred for planets with reduced mantles producing Class R atmospheres. On warm, volcanically active planets, mantle f O 2 could be identifiable from atmospheric observations using JWST.

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Low volcanic outgassing rates for a stagnant lid Archean earth with graphite-saturated magmas

Cited by 19 publications

References 95 publications

The case and context for atmospheric methane as an exoplanet biosignature

The case and context for atmospheric methane as an exoplanet biosignature

Interior heating and outgassing of Proxima Centauri b: Identifying critical parameters

Growth and evolution of secondary volcanic atmospheres: I. Identifying the geological character of warm rocky planets

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