Abstract:
The imprints of stellar nucleosynthesis and chemical evolution of the galaxy can be seen in different stellar
populations, with older generation stars showing higher α-element abundances and the later generations becoming
enriched with iron-peak elements. The evolutionary connections and chemical characteristics of circumstellar
disks, stars, and their planetary companions can be inferred by studying the interdependence of planetary and host
star properties. Numerous studies in the past have confirmed that high-mass giant planets are commonly found
around metal-rich stars, while the stellar hosts of low-mass planets have a wide range of metallicity. In this work,
we analyzed the detailed chemical abundances for a sample of >900 exoplanet hosting stars drawn from different
radial velocity and transit surveys. We correlate the stellar abundance trends for α- and iron-peak elements with the
planets’ mass. We find the planet mass–abundance correlation to be primarily negative for α-elements and
marginally positive or zero for the iron-peak elements, indicating that stars hosting giant planets are relatively
younger. This is further validated by the age of the host stars obtained from isochrone fitting. The later enrichment
of protoplanetary material with iron and iron-peak elements is also consistent with the formation of the giant
planets via the core accretion process. A higher metal fraction in the protoplanetary disk is conducive to rapid core
growth, thus providing a plausible route for the formation of giant planets. This study, therefore, indicates that the
observed trends in stellar abundances and planet mass are most likely a natural consequence of Galactic chemical
evolution.
