The chemical evolution of the solar neighbourhood for planet-hosting stars

Abstract

Theoretical physical-chemical models for the formation of planetary systems depend on data quality for the Sun’s composition, that of stars in the solar neighbourhood, and of the estimated ”pristine” compositions for stellar systems. The effective scatter and the observational uncertainties of elements within a few hundred parsecs from the Sun, even for the most abundant metals like carbon, oxygen and silicon, are still controversial. Here we analyse the stellar production and the chemical evolution of key elements that underpin the formation of rocky (C, O, Mg, Si) and gas/ice giant planets (C, N, O, S). We calculate 198 galactic chemical evolution (GCE) models of the solar neighbourhood to analyse the impact of different sets of stellar yields, of the upper mass limit for massive stars contributing to GCE (Mup) and of supernovae from massive-star progenitors which do not eject the bulk of the iron-peak elements (faint supernovae). Even considering the GCE variation produced via different sets of stellar yields, the observed dispersion of elements reported for stars in the Milky Way disk is not reproduced. Among others, the observed range of super-solar [Mg/Si] ratios, sub-solar [S/N], and the dispersion of up to 0.5 dex for [S/Si] challenge our models. The impact of varying Mup depends on the adopted supernova yields. Thus, observations do not provide a constraint on the Mup parametrization. When including the impact of faint supernova models in GCE calculations, elemental ratios vary by up to 0.1-0.2 dex in the Milky Way disk; this modification better reproduces observations.

Connections between Planetary Populations and Chemical Characteristics of Their Host Stars

“…Previous studies recognized that corrections for GCE are a crucial step for accurately evaluating the abundance trend of PHSs in the abundance-T C plane (Adibekyan et al 2014;Spina et al 2016;Bedell et al 2018). GCE refers to how chemical elements formed and were distributed in the MW (Gibson et al 2003;Spina et al 2016;Pignatari et al 2023). The formation rate and the amount of elements created vary depending on the star formation rate and initial mass function.…”

“…They further demonstrated that the depletion trend is real, after carefully correcting for the GCE effects in their Sun-like stars. Such a study indicates that the GCE correction is a vital step when comparing stars with different ages but similar metallicity and temperatures (e.g., Gibson et al 2003;Spina et al 2016Spina et al , 2018Pignatari et al 2023). Other studies (Adibekyan et al 2014;Nissen 2015;Spina et al 2016) also show that a careful selection of the comparison stars with similar stellar parameters is crucial, due to the presence of correlations between stellar parameters and chemical abundance patterns before the application of the GCE correction.…”

Presupernova Evolution and Explosive Nucleosynthesis of Rotating Massive Stars. II. The Supersolar Models at [Fe/H] = 0.3

“…A few years ago (hereinafter LC18) published an extended set of models and yields of massive stars in the metallicity range −3 [Fe/H] 0 and with initial rotation velocities in the range 0-300 km s −1 . Those results were mainly intended as a database to be used in galactic chemical evolution (GCE) models (e.g., Prantzos et al 2018;Palla et al 2022;Vasini et al 2022;Pignatari et al 2023;Prantzos et al 2023;Womack et al 2023). In an additional paper (Roberti et al 2024) we explored the influence of rotation on the evolution and nucleosynthesis of massive stars also at metallicities between primordial (Z = 0) and [Fe/H] = −4.…”