Generalized Predictions for the Electromagnetic Signatures of Mirror Stars

TL;DR

This paper models the structure and emission spectra of optically thick mirror star nuggets, predicting their observable signatures to aid in their detection using existing astronomical data.

Contribution

It provides the first comprehensive analysis of optically thick mirror star nuggets across a wide parameter space, including their spectra and distinguishable features.

Findings

Optically thick mirror star nuggets occupy distinct regions in HR and gravity diagrams.

Predictions enable differentiation of mirror stars from regular stars in stellar catalogues.

Publicly available models facilitate realistic searches for mirror star signals.

Abstract

Mirror Stars are a generic prediction of dissipative dark matter models, including minimal atomic dark matter and twin baryons in the Mirror Twin Higgs. Mirror Stars capture regular atoms from the interstellar medium through highly suppressed kinetic mixing interactions between the regular and the dark photon. This results in the accumulation of a "nugget", which draws heat from the mirror star core and emits distinctive X-ray and optical signals. In this work, we solve the stellar structure equations of optically thick nuggets across a wide range of the effective mirror star parameter space, and characterize their emission spectra using stellar atmosphere models. This complements an earlier analysis of lower-mass optically thin nuggets. We find that optically thick mirror star nuggets occupy distinct regions of the (stellar surface temperature, luminosity, surface gravity) space, and can be distinguished from regular stars in both HR diagrams and temperature-surface-gravity diagrams using astrometric and spectroscopic stellar catalogues. Our detailed predictions, which are publicly available, now give for the first time a general picture of mirror star signals in the optical and IR to enable realistic mirror star searches using existing catalogues and new telescope observations.