Spectroscopic Survey of Small Solar System Bodies with Ariel

The small Solar System bodies (SSSBs) preserve records of the formation and evolution of the Solar System. In particular, the near-infrared wavelength region around 3 $μ$m provides crucial insights into the origin and transport of hydrated materials and organics, although it is difficult to observe from the ground because of strong telluric absorption. We assess the observability of SSSBs as complementary science to the ESA Ariel space mission, operating in the visible to mid-infrared wavelength range (0.5--7.8 $μ$m). Using the NASA JPL Horizons ephemeris system, we evaluate the visibility of known SSSBs from 2032 to 2035. Our analysis shows that Ariel can spectroscopically characterize up to 402 unique SSSBs under a conservative limiting visual magnitude of $V=13.6$. If observations can be extended to somewhat fainter targets ($V=16$), the number of observable SSSBs could increase to 2144. Assuming operational scenarios in which one SSSB is observed every 3, 7, or 30 days over a four-year mission, the total numbers of observable targets would be 357, 209, and 49, respectively. We further model the spectral energy distributions of candidate targets to evaluate their observational performance. We demonstrate that Ariel can resolve critical absorption features, such as those at 2.7 $μ$m and 3.4 $μ$m, with a higher spectral resolution than the previous infrared survey with AKARI. Observations of SSSBs with Ariel can provide insights into the distribution and evolution of life-forming materials in the Solar System and constitute a scientifically compelling component of Ariel's complementary science program.