Unveiling the Trans-Neptunian Region with the SKA

Abstract

We explore the potential of the SKA staged delivery AA4 (SKA-AA4) to detect and characterise the thermal emission of trans-Neptunian objects (TNOs) and Centaurs at centimetre wavelengths. These distant icy bodies preserve important information on the formation and evolution of the outer Solar System and provide a valuable link to planetary systems observed around other stars. The unprecedented sensitivity of SKA-AA4 will enable thermal detections of several of the brightest TNOs and Centaurs, extending radiometric studies beyond the capabilities of current radio facilities. Combined with shorter-wavelength observations and occultation measurements, these data will provide new constraints on spectral emissivity behaviour, thermophysical properties, and subsurface structure. At its highest angular resolutions, SKA-AA4 may partially resolve the largest systems, enabling investigations of surface heterogeneity, extended structures such as rings, and the partial resolution of some wide binary systems. We also assess the feasibility of radio occultation observations, which can provide independent constraints on object sizes, shapes, atmospheres, rings, or satellites. Together with observations from ALMA, JWST, and occultation campaigns, SKA-AA4 will establish centimetre-wavelength studies as a powerful new tool for investigating the thermal and structural properties of outer Solar System bodies.