Exoplanets as Sub-GeV Dark Matter Detectors

Understand

We present exoplanets as new targets to discover Dark Matter (DM).

• Throughout the Milky Way, DM can scatter, become captured, deposit annihilation energy, and increase the heat flow within exoplanets.
• We estimate upcoming infrared telescope sensitivity to this scenario, finding actionable discovery or exclusion searches.
• We find that DM with masses above about an MeV can be probed with exoplanets at DM-proton and DM-electron scattering cross sections down to about $10^{-37}$cm$^2$, stronger than existing limits by up to six orders of magnitude.