The bulk metallicity of giant planets around M stars

Fuente: arXiv
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Main Authors: Müller, Simon, Helled, Ravit
Format: Preprint
Published: 2024
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author Müller, Simon
Helled, Ravit
author_facet Müller, Simon
Helled, Ravit
contents The bulk-metallicity determination of giant exoplanets is essential to constrain their formation and evolution pathways and to compare them to the solar system. Previous studies inferred an inverse relation between the mass and bulk metallicity. However, the data almost exclusively contained planets that orbit FGK stars. The recent discoveries of giant exoplanets around M-dwarf stars present an opportunity to probe whether they follow a mass-metallicity trend different from that of their FGK counterparts. Using evolution models we characterised the interiors of giant exoplanets with reliable mass-radius measurements that orbit FGK and M-dwarf stars. We then inferred the mass-metallicity trends for both populations. We found that the bulk metallicity of giant planets around M stars is overall lower compared to those around FGK stars. This yielded mass-metallicity relations for the two populations with similar slopes but significantly different offsets. The lack of metal-rich giant planets around M dwarfs could explain the difference in the inferred offset and be a result of different formation conditions. However, there were only 20 successful bulk-metallicity retrievals for the giant planets around M dwarfs, which resulted in rather large uncertainties. Therefore, it is of great importance to continue detecting these planets with both transit and radial velocities. Additionally, the characterisation of the atmospheres of giant planets around M-stars can further help to constrain their interiors and to investigate the atmosphere-interior connection. This will significantly contribute towards understanding the possible formation pathways of giant planets.
format Preprint
id arxiv_https___arxiv_org_abs_2411_16197
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The bulk metallicity of giant planets around M stars
Müller, Simon
Helled, Ravit
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
The bulk-metallicity determination of giant exoplanets is essential to constrain their formation and evolution pathways and to compare them to the solar system. Previous studies inferred an inverse relation between the mass and bulk metallicity. However, the data almost exclusively contained planets that orbit FGK stars. The recent discoveries of giant exoplanets around M-dwarf stars present an opportunity to probe whether they follow a mass-metallicity trend different from that of their FGK counterparts. Using evolution models we characterised the interiors of giant exoplanets with reliable mass-radius measurements that orbit FGK and M-dwarf stars. We then inferred the mass-metallicity trends for both populations. We found that the bulk metallicity of giant planets around M stars is overall lower compared to those around FGK stars. This yielded mass-metallicity relations for the two populations with similar slopes but significantly different offsets. The lack of metal-rich giant planets around M dwarfs could explain the difference in the inferred offset and be a result of different formation conditions. However, there were only 20 successful bulk-metallicity retrievals for the giant planets around M dwarfs, which resulted in rather large uncertainties. Therefore, it is of great importance to continue detecting these planets with both transit and radial velocities. Additionally, the characterisation of the atmospheres of giant planets around M-stars can further help to constrain their interiors and to investigate the atmosphere-interior connection. This will significantly contribute towards understanding the possible formation pathways of giant planets.
title The bulk metallicity of giant planets around M stars
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2411.16197