Debris disks and their properties with the Habitable Worlds Observatory

TL;DR

Debris disks illuminate the late stages of planet formation and potential volatile delivery to terrestrial planets. The paper argues that Habitable Worlds Observatory's combination of diffraction-limited UV-optical imaging and high-resolution spectroscopy will enable detailed mapping of dust composition, substructures, and gas in debris disks, including the terrestrial zone, and may reveal embedded planets through disk features. By integrating analyses of the scattering phase function, polarimetry, and integral-field spectroscopy, the approach aims to constrain dust properties and gas content with unprecedented sensitivity and spatial resolution. This work holds promise for advancing our understanding of how rocky planets acquire volatiles and how planetary systems evolve, with direct implications for assessing planetary habitability.

Abstract

The study of the last stages of planet formation, also known as debris disks, is fundamental to place constrains on the formation of planetary sized bodies. Debris disks are composed of dust and occasionally small amounts of gas, both released through dynamical interactions of small rocky bodies and dust particles, such as collisions and evaporation. The distribution of the dust can reveal the presence of forming planets and its composition can directly trace that of comets, asteroids and even planets. While we have been observing debris disks for 40 years now, most observations so far have been restricted to the cold outer regions of the system, and therefore information of the terrestrial zone is still missing. The improved spatial resolution, inner working angle and sensitivity that the Habitable Worlds Observatory will provide will enable a much closer look into the structure and composition of debris disks (particularly of its inner region) and enable the search for the forming rocky planets within the disk.

Figures (2)

• Figure 2: Figure from Pawellek24. The scattering phase function varies for different sizes and dust compositions
• Figure 3: Figure from Rebollido24. The debris disk around Beta Pictoris seen with JWST/MIRI.