The modelled angular velocity evolution of stars of different masses, initial rotation periods and metallicities. The masses considered are 0.5π (left panel), 0.7π (middle panel) and 1π (right panel). The initial periods considered are 1 day (dashed lines) and 10 days (solid lines). The metallicities considered are -1 dex (dark blue lines), -0.5 dex (purple lines), 0 dex (orange lines) and +0.5 dex (yellow lines). The point at which the star transitions from the saturated to unsaturated regime (at Rocrit = 0.2) is indicated by a triangle along each track. β astro-ph.EP
Understanding how exoplanet atmospheres evolve is a key question in the context of habitability. One key process governing this evolution is atmospheric evaporation by stellar X-ray and EUV emission (collectively, XUV).
As such, the evolution of exoplanet atmospheres is closely tied to the evolution of the host starβs magnetic activity. Many studies have modelled the combined evolution of exoplanet atmospheres and their host stars. However, to date, the impact of the host starβs metallicity on stellar activity/exoplanet atmosphere evolution has not been explored.
In this work, we investigate how stellar metallicity affects the rotation and activity evolution of solar-like stars as well as the corresponding exoplanet atmospheric evolution.
We reconfirm previous results that metal-rich stars spin down more rapidly than metal-poor stars. We also find that the XUV flux that an exoplanet in the habitable zone of its host star receives is larger when the host star is more metal-rich. As such, the atmospheres of exoplanets in the habitable zones of metal-rich stars are evaporated more rapidly than exoplanets in the habitable zones of metal-poor stars.
Lastly, we find that the atmospheric evolution is most sensitive to the host star metallicity when the host star has a higher mass. In the highest mass solar-stars, the metallicity can have a larger influence on the atmospheric evolution than the initial rotation period of the star.
Victor See, Charlotte Fairman, Louis Amard, Oliver Hall
Comments: 12 pages, 7 figures, accepted for publication in MNRAS
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2509.21276 [astro-ph.EP] (or arXiv:2509.21276v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2509.21276
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Submission history
From: Victor See
[v1] Thu, 25 Sep 2025 15:01:47 UTC (428 KB)
https://arxiv.org/abs/2509.21276
Astrobiology, astronomy,
