Dark matter energy exchange in stars orbiting supermassive black holes

Stars on tight orbits around the supermassive black hole at the Galactic Center pass through regions where the dark matter~(DM) density may be strongly enhanced. We compute the orbit-averaged DM-induced energy exchange for S4714 as an example. It is a star on an exceptionally close and relativistic orbit around Sagittarius~A*. For a spiked dark matter profile, the exchange reaches the stellar luminosity at ${\sigma }_{\chi p}\sim {10}^{-36}{\mathrm{c}\mathrm{m}}^2$ for MeV-GeV masses and ${\sigma }_{\chi e}\sim 5\times {10}^{-38}{\mathrm{c}\mathrm{m}}^2$ for sub-MeV masses, opening a new annihilation-free route toward dark-star phases. These cross sections lie within the range predicted by freeze-in scenarios and are consistent with cosmic-ray–boosted and solar-reflection dark matter constraints.