Signatures of Mirror Stars

Understand

Motivated by theories of Neutral Naturalness, we argue that \emph{Mirror Stars} are a generic possibility in any hidden sector with analogues of Standard Model (SM) electromagnetism and nuclear physics.

• We show that if there exists a tiny kinetic mixing between the dark photon and the SM photon, Mirror Stars capture SM matter from the interstellar medium, which accumulates in the core of the Mirror Star and radiates in the visible spectrum.
• This signature is similar to, but in most cases much fainter than, ordinary white dwarfs.
• We also show for the first time that in the presence of captured SM matter, a fraction of dark photons from the core of the Mirror Star convert directly to SM photons, which leads to an X-ray signal that represents a direct probe of the properties of the Mirror Star core.