Plausible constraints on the range of bulk terrestrial exoplanet compositions in the Solar neighbourhood
arXiv:2211.01800 · doi:10.3847/1538-4357/acac7d
Abstract
Rocky planet compositions regulate planetary evolution by affecting core sizes, mantle properties, and melting behaviours. Yet, quantitative treatments of this aspect of exoplanet studies remain generally under-explored. We attempt to constrain the range of potential bulk terrestrial exoplanet compositions in the solar neighbourhood (<200 pc). We circumscribe probable rocky exoplanet compositions based on a population analysis of stellar chemical abundances from the Hypatia and GALAH catalogues. We apply a devolatilization model to simulate compositions of hypothetical, terrestrial-type exoplanets in the habitable zones around Sun-like stars, considering elements O, S, Na, Si, Mg, Fe, Ni, Ca, and Al. We further apply core-mantle differentiation by assuming constant oxygen fugacity, and model the consequent mantle mineralogy with a Gibbs energy minimisation algorithm. We report statistics on several compositional parameters and propose a reference set of (21) representative planet compositions for using as end-member compositions in imminent modelling and experimental studies. We find a strong correlation between stellar Fe/Mg and metallic core sizes, which can vary from 18 to 35 wt%. Furthermore, stellar Mg/Si gives a first-order indication of mantle mineralogy, with high-Mg/Si stars leading to weaker, ferropericlase-rich mantles, and low-Mg/Si stars leading to mechanically stronger mantles. The element Na, which modulates crustal buoyancy and mantle clinopyroxene fraction, is affected by devolatilization the most. While we find that planetary mantles mostly consist of Fe/Mg-silicates, core sizes and relative abundances of common minerals can nevertheless vary significantly among exoplanets. These differences likely lead to different evolutionary pathways among rocky exoplanets in the solar neighbourhood.
Accepted by the Astrophysical Journal
References in corpus (36)
- The GALAH Survey: Scientific Motivation
- alpha-, r-, and s-process element trends in the Galactic thin and thick disks
- Can we constrain interior structure of rocky exoplanets from mass and radius measurements?
- Stellar Abundances in the Solar Neighborhood: The Hypatia Catalog
- Revisited Mass-Radius relations for exoplanets below 120 Earth masses
- A First Constraint on the Thick Disk Scale Length: Differential Radial Abundances in K Giants at Galactocentric Radii 4, 8, and 12 kpc
- The Occurrence of Rocky Habitable Zone Planets Around Solar-Like Stars from Kepler Data
- Challenges in Planet Formation
- Oxygen fugacities of extrasolar rocks: Evidence for an Earth-like geochemistry of exoplanets
- Stellar chromospheric activity of 1,674 FGK stars from the AMBRE-HARPS sample I. A catalogue of homogeneous chromospheric activity
- The Elemental Abundances (with Uncertainties) of the Most Earth-like Planet
- The temporal evolution of neutron-capture elements in the Galactic discs
- A new class of Super-Earths formed from high-temperature condensates: HD219134 b, 55 Cnc e, WASP-47 e
- Constraining planet structure and composition from stellar chemistry: trends in different stellar populations
- Chemistry in an Evolving Protoplanetary Disk: Effects on Terrestrial Planet Composition
- Influence of sub- and super-solar metallicities on the compositions of solid planetary building blocks
- Bayesian analysis of interiors of HD 219134b, Kepler-10b, Kepler-93b, CoRoT-7b, 55 Cnc e, and HD 97658b using stellar abundance proxies
- A Comparison of Stellar Elemental Abundance Techniques and Measurements
- Scaling of plate-tectonic convection with pseudoplastic rheology
- Thermodynamics of Element Volatility and its Application to Planetary Processes
- Are exoplanetesimals differentiated?
- A Unified tool to estimate Distances, Ages and Masses (UniDAM) from spectrophotometric data
- Characterisation of the hydrospheres of TRAPPIST-1 planets
- Predictions for Observable Atmospheres of Trappist-1 Planets from a Fully Coupled Atmosphere-Interior Evolution Model
- Chemical Diversity of Super-Earths As a Consequence of Formation
- BAFFLES: Bayesian Ages for Field Lower-Mass Stars
- Stochastic accretion of the Earth
- Polluted White Dwarfs Reveal Exotic Mantle Rock Types on Exoplanets in our Solar Neighborhood
- Detailed chemical compositions of planet hosting stars: I. Exploration of possible planet signatures
- Rocklines as Cradles for Refractory Solids in the Protosolar Nebula
- Bayesian constraints on the origin and geology of exo-planetary material using a population of externally polluted white dwarfs
- Host-star and exoplanet compositions: a pilot study usinga wide binary with a polluted white dwarf
- Forming planets around stars with non-solar elemental composition
- A Concise Treatise on Converting Stellar Mass Fractions to Abundances to Molar Ratios
- Detailed chemical compositions of planet-hosting stars: II. Exploration of the interiors of terrestrial-type exoplanets
- Planetary thermal evolution models with tectonic transitions
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- Setting the stage for the search for life with the Habitable Worlds Observatory: Properties of 164 promising planet survey targets
- Super-Earths and Earth-like Exoplanets
- Planet formation throughout the Milky Way: Planet populations in the context of Galactic chemical evolution
- A mineralogical reason why all exoplanets cannot be equally oxidising
- Interior Controls on the Habitability of Rocky Planets
- The chemical evolution of the solar neighbourhood for planet-hosting stars
- Linking the primordial composition of planet building disks to the present-day composition of rocky exoplanets
- Revisiting equilibrium condensation and rocky planet compositions: Introducing the ECCOplanets code
- Precise Transit Photometry Using TESS: Updated Physical Properties for 28 Exoplanets Around Bright Stars
- Geodynamics of super-Earth GJ 486b
- Proto-planetary disk composition-dependent element volatility in the context of rocky planet formation
- Exo-Geoscience Perspectives Beyond Habitability
- Towards characterising rocky worlds: Trends in chemical make-ups of M dwarfs versus GK dwarfs
- A novel metric for assessing climatological surface habitability
- A chemical perspective on planet formation in reduced systems