The impact of stellar binaries and star cluster dynamics on pair-instability supernovae

Pair-instability supernovae (PISNe) are among the most luminous transients in the Universe. However, they have never been confidently observed. Solving this puzzle would have key implications for several astrophysical topics, including galaxy chemical enrichment, the interpretation of gravitational waves from binary black hole mergers, and the nature of red dropout sources seen by JWST. With this aim, we present the first in-depth study of PISN occurrence in binary stars, both in isolation and in dense star clusters. We employed the stellar tracks, to evolve a suite of 35 synthetic binary populations, including variations on formation channels, cluster properties, and upper limits of the stellar initial mass function. Combining this with an up-to-date, semi-empirical determination of the metallicity-dependent star formation rate density, we provide new results on the cosmic rate of PISNe. code, with state-of-the-art parsec We find that binary interactions can boost the PISN rate by as much as threefold relative to single stars, whereas binary hardening can either enhance or suppress PISN production, depending on whether the progenitors are primordial or dynamically formed. Moreover, we showcase how our comprehensive framework for the cosmic PISN rate can be used to constrain uncertain aspects of stellar and galaxy evolution models via comparison with observations, including the recipes for stellar-wind mass loss in very massive stars and the galaxy metallicity distribution throughout the Universe.