Spaargaren, Rob JJ;
Wang, Haiyang SS;
Mojzsis, Stephen JJ;
Ballmer, Maxim DD;
Tackley, Paul JJ;
(2023)
Plausible Constraints on the Range of Bulk Terrestrial Exoplanet Compositions in the Solar Neighborhood.
The Astrophysical Journal
, 948
(1)
, Article 53. 10.3847/1538-4357/acac7d.
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Abstract
Rocky planet compositions regulate planetary evolution by affecting core sizes, mantle properties, and melting behaviors. Yet, quantitative treatments of this aspect of exoplanet studies remain generally underexplored. We attempt to constrain the range of potential bulk terrestrial exoplanet compositions in the solar neighborhood (<200 pc). We circumscribe probable rocky exoplanet compositions based on a population analysis of stellar chemical abundances from the Hypatia and GALAH catalogs. 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 minimization algorithm. We report statistics on several compositional parameters and propose a reference set of (21) representative planet compositions for use as end-member compositions in imminent modeling 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, the 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 neighborhood.
| Type: | Article |
|---|---|
| Title: | Plausible Constraints on the Range of Bulk Terrestrial Exoplanet Compositions in the Solar Neighborhood |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/1538-4357/acac7d |
| Publisher version: | http://doi.org/10.3847/1538-4357/acac7d |
| Language: | English |
| Additional information: | Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. |
| Keywords: | Science & Technology, Physical Sciences, Astronomy & Astrophysics, GALACTIC CHEMICAL EVOLUTION, 55 CNC E, SUPER-EARTHS, INTERIOR STRUCTURE, ROCKY EXOPLANETS, CONDENSATION TEMPERATURES, ELEMENTAL ABUNDANCES, DEPENDENT VISCOSITY, TRAPPIST-1 PLANETS, DISLOCATION CREEP |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10170974 |
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