Exozodi Structures as Signposts of Terrestrial Planets

Exozodiacal dust clouds ("exozodis")—circumstellar disks of warm (a few 100 Kelvin) dust, broadly distributed around a star's habitable zone—pose both a challenge and an opportunity for direct imaging. While they can obscure or outshine terrestrial planets, their structural features may also serve as tracers of planetary dynamics. Interferometric surveys of mid-infrared excesses have detected exozodis around ~20% of nearby main-sequence stars, though only at sensitivities of tens to hundreds of zodis (with 1 zodi corresponding to the Solar System's level), suggesting that fainter exozodis may be even more common. While the detection of exo-Earths with METIS high-contrast imaging remains challenging, exozodis may be more readily detected—and spatially resolved—providing a potential avenue for characterizing habitable-zone planetary systems without directly imaging the planets themselves. Here we present modeling results exploring two classes of zodi structures generated by terrestrial-mass planets and assess their observability with METIS in the N-band.