When a massive star runs out of fuel, its core collapses and a shock wave races outward. But even before the star tears apart, particles that barely interact with ordinary matter may be born in its depths. If they decay into light, that energy leaks into the dense gas around the star.
This gas, like a blanket, wraps the star. The injected energy heats it, and the gas begins to shine like a hot lightbulb. Such light could be spotted before the main flash. Astronomers tested this on the supernova SN 2023ixf: early observations showed no extra glow. So candidate particles, such as dark photons, either aren't born or live too briefly.
The absence of a signal is also a result. It allowed scientists to rule out entire regions of parameter space where such particles could exist. In the future, when a supernova goes off in our Galaxy, this method could help us peer into the dark sector of the Universe.
as written by the authors arXiv:2603.09615
We propose a novel strategy to probe feebly-interacting particles (FIPs) by exploiting the dense, confined circumstellar medium (CSM) surrounding core-collapse supernovae (CCSNe). FIPs produced in the proto-neutron star can deposit substantial visible energy into the CSM via decay prior to the shock breakout from the progenitor star. This energy injection heats and ionizes the CSM, establishing a FIP-induced photosphere that generates distinctive precursor blackbody emission. Using early-time observations of SN 2023ixf, we translate the non-detection of excessive precursor luminosity into stringent new constraints on MeV-scale dark photons as an exemplary model. Our results significantly extend existing CCSN bounds and exclude previously unexplored regions of parameter space. We further demonstrate that the FIP-induced dust sublimation offers robust diagnostics for future Galactic SNe, opening a new avenue to explore the dark sector.
Supernova SN 2023ixf erupted in the Pinwheel Galaxy, just 21 million light-years away — practically next door by cosmic standards.