Francesco Gabrielli (Uppsala University): The impact of stellar binaries and star cluster dynamics on the emergence of pair-instability supernovae

Thursday 11 Jun 2026, 14:00 → 15:00 Europe/Stockholm

Å101130

Title: The impact of stellar binaries and star cluster dynamics on the emergence of pair-instability supernovae 
Speaker: Francesco Gabrielli 
Affiliation: Uppsala University 
Room: Å101130 
Time: 14:00-15:00 

Abstract: 
Pair-instability supernovae (PISNe) are an elusive class of transients representing the final fate of low-metallicity, very-massive stars. Despite their extreme expected luminosities - up to one hundred times those of typical core-collapse supernovae - they have never been confidently observed. Solving this long-standing 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 high-redshift sources seen by JWST. However, studies of PISNe have largely focused on single-stellar progenitors, despite the fact that most very-massive stars are expected to reside in binaries or even higher-order multiple systems. Moreover, PISNe can arise in a wide variety of galactic environments, from low-density regions to dense star clusters.
In this seminar, I will present an in-depth study on the impact of binary evolution and dynamical interactions on the emergence of PISNe. We employ the population synthesis code SEVN, equipped with PARSEC stellar tracks, to simulate the evolution of binary PISN progenitors, and model the effect of external perturbers on their orbits in globular, young, and nuclear star clusters. Combining these results with an up-to-date, metallicity-dependent star formation history, we provide a comprehensive framework for the PISN rate as a function of redshift. I will describe how the PISN rate is shaped by variations in formation channels, cluster properties, and the upper limit of the stellar initial mass function. In addition, I will identify the most-efficient galactic environments for producing PISNe, and showcase the potential of future PISN observations to resolve major uncertainties in stellar and galaxy evolution models - including stellar-wind mass-loss prescriptions for very-massive stars, and the galaxy metallicity distribution across cosmic time.