Issue |
A&A
Volume 674, June 2023
|
|
---|---|---|
Article Number | A137 | |
Number of page(s) | 12 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202245387 | |
Published online | 16 June 2023 |
Quantitative correlation of refractory elemental abundances between rocky exoplanets and their host stars
1
State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology,
Macau
999078,
PR China
e-mail: ddni@must.edu.mo
2
CNSA Macau Center for Space Exploration and Science,
Macau
999078,
PR China
3
Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education,
Zhuhai
519000,
PR China
Received:
7
November
2022
Accepted:
17
April
2023
Context. Stellar elemental abundances are generally used to constrain the interiors of rocky exoplanets by assuming planet’s relative abundances of major refractory elements (Fe, Mg, and Si) are similar to those of their host stars. Very recently, a non-one-to-one correlation was found among the compositions of low-mass planets and their host stars. It is therefore of great interest to further explore this correlation for larger samples of rocky exoplanets.
Aims. We focus on a large sample of rocky exoplanets and compute their bulk elemental abundance ratios. We analyze the quantitative correlation between rocky exoplanets and their host stars by comparing the abundance ratios of these refractory elements.
Methods. The interior of rocky exoplanets is assumed to be an iron-rich core overlaid with a silicate mantle. We constrained the bulk composition of rocky exoplanets from their measured mass and radius, using Bayesian statistical approaches. Then we used orthogonal distance regression (ODR) to characterize the compositional correlation between rocky exoplanets and their host stars.
Results. Some rocky exoplanets are shown to have high iron-mass fractions and are thus likely to be iron-enriched super-Mercuries. We find the iron content of rocky exoplanets is dependent on the metallicity [Fe/H] of their host stars. The planets formed around a higher metallicity star generally span a wider range of iron masses, allowing for a higher iron content. Moreover, we directly compared the iron-mass fractions of rocky exoplanets with those deduced from the refractory elemental abundance ratios of their host stars. The results suggest that most rocky planets are more iron-enriched with respect to the initial protoplanetary disk.
Key words: planetary systems / stars: abundances / planets and satellites: composition / planets and satellites: interiors / methods: statistical
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.