Speaker
Description
Dark matter (DM) constitutes most of the matter content of the Universe, yet its particle nature remains unknown. While laboratory searches and cosmological probes have placed strong constraints on many candidate models, astrophysical environments provide a complementary avenue to test DM interactions under extreme conditions. Stars are particularly promising laboratories: as they move through their host halos, DM particles may scatter with stellar constituents, lose energy, and become gravitationally captured. Once accumulated, DM can alter stellar evolution through annihilation heating, enhanced luminosity, or—in the case of heavy non-annihilating DM—through self-gravitation and eventual collapse. Understanding capture in realistic stellar environments is therefore essential for connecting stellar observations to particle DM physics.
In this talk, I will discuss the capture of heavy DM in rapidly evolving massive stars, with emphasis on the first stellar populations and their later metal-enriched descendants. Using stellar evolution simulations from the zero-age main sequence to advanced burning stages, we show that DM capture depends sensitively on the changing internal structure and composition of the star. During the early hydrogen- and helium-dominated phases, capture is largely controlled by scattering on light nuclei. As nuclear burning proceeds, metal production generates a dense core surrounded by a lighter envelope, substantially enhancing the capture of ultra-heavy DM and requiring a multi-component treatment with several nuclear targets.
I will also highlight recent advances in the theory of heavy-DM capture in compact stars, where multiple scatterings, realistic trajectories, nuclear form factors, and in-medium thermalization effects become crucial. These developments clarify how efficiently heavy DM can be trapped and transported to stellar centers, and how rapidly it can thermalize after capture.
Our results indicate that, for viable regions of parameter space beyond current direct-detection bounds, heavy annihilating DM may reach capture–annihilation equilibrium within the short lifetime of a massive star. For non-annihilating DM, the accumulated population can become self-gravitating and potentially collapse into a black hole capable of consuming the host star from within. These findings demonstrate that accurate stellar modeling, combined with improved capture formalisms, opens a powerful new window on heavy DM through massive stars and stellar remnants.