TY - JOUR
T1 - A link between rocky planet composition and stellar age
AU - Weeks, Angharad
AU - Van Eylen, Vincent
AU - Huber, Daniel
AU - Kawata, Daisuke
AU - Stokholm, Amalie
AU - Børsen-Koch, Victor Aguirre
AU - Pinilla, Paola
AU - Rørsted, Jakob Lysgaard
AU - Winther, Mark Lykke
AU - Berger, Travis
N1 - Publisher Copyright:
© 2025 The Author(s).
PY - 2025/5
Y1 - 2025/5
N2 - Interior compositions are key for our understanding of Earth-like exoplanets. The composition of the core can influence the presence of a magnetic dynamo and the strength of gravity on the planetary surface, both of which heavily impact thermal and possible biological processes and thus the habitability for life and its evolution on the planet. However, detailed measurements of the planetary interiors are extremely challenging for small exoplanets, and existing data suggest a wide diversity in planet compositions. Hitherto, only certain photospheric chemical abundances of the host stars have been considered as tracers to explain the diversity of exoplanet compositions. Here, we present a homogeneous analysis of stars hosting rocky exoplanets, with ages between 2 and 14 Gyr, revealing a correlation between rocky exoplanet compositions and the ages of the planetary systems. Denser rocky planets are found around younger stars. This suggests that the compositional diversity of rocky exoplanets can be linked to the ages of their host stars. We interpret this to be a result of chemical evolution of stars in the Milky Way, which modifies the material out of which stars and planets form. The results imply that rocky planets that form today, at similar Galactocentric radii, may have different formation conditions, and thus different properties than planets that formed several billion years ago, such as the Earth.
AB - Interior compositions are key for our understanding of Earth-like exoplanets. The composition of the core can influence the presence of a magnetic dynamo and the strength of gravity on the planetary surface, both of which heavily impact thermal and possible biological processes and thus the habitability for life and its evolution on the planet. However, detailed measurements of the planetary interiors are extremely challenging for small exoplanets, and existing data suggest a wide diversity in planet compositions. Hitherto, only certain photospheric chemical abundances of the host stars have been considered as tracers to explain the diversity of exoplanet compositions. Here, we present a homogeneous analysis of stars hosting rocky exoplanets, with ages between 2 and 14 Gyr, revealing a correlation between rocky exoplanet compositions and the ages of the planetary systems. Denser rocky planets are found around younger stars. This suggests that the compositional diversity of rocky exoplanets can be linked to the ages of their host stars. We interpret this to be a result of chemical evolution of stars in the Milky Way, which modifies the material out of which stars and planets form. The results imply that rocky planets that form today, at similar Galactocentric radii, may have different formation conditions, and thus different properties than planets that formed several billion years ago, such as the Earth.
KW - exoplanets –
KW - Galaxy: evolution
KW - planets and satellites: formation
KW - stars: solar-type
UR - http://www.scopus.com/inward/record.url?scp=105002581202&partnerID=8YFLogxK
U2 - 10.1093/mnras/staf474
DO - 10.1093/mnras/staf474
M3 - Journal article
AN - SCOPUS:105002581202
SN - 0035-8711
VL - 539
SP - 405
EP - 421
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -