Preliminary results from an ultra-sensitive search for trans-Neptunian objects with JWST

The size distribution of the cold classical trans-Neptunian objects (TNOs), which can be inferred from their observed magnitude distribution, is crucial for testing theoretical models of planet formation because it reflects the outcomes of accretion, collisional processes, and dynamical evolution over the history of the Solar System. Therefore, comparing the observed size distribution with those predicted by models helps to constrain the proposed physical processes and underlying initial conditions that shaped the current Solar System. However, current streaming instability simulations have yet to completely reproduce the observed size distribution of the planetesimals primarily because of the low number statistics for small TNOs (diameters less than ~50 km), and the relative faintness of TNOs generally limits ground-based searches to magnitudes no fainter than 27. Thus, the faint (small) size distribution of TNOs remains fairly uncertain, significantly hindering detailed modeling and further understanding of Solar System formation.

In this talk, we will present preliminary results from our pencil beam survey that utilized JWST to search and characterize ultra-faint TNOs to further constrain Solar System formation models. Our JWST cycle 1 program #1568 is a 3-epoch survey that observed 0.05 square degrees of the sky. With the sensitivity of this survey, we expect to detect and characterize TNOs as small as 5 km in diameter. This is the deepest Solar System survey to date, with at least a visible magnitude deeper than the landmark TNO survey by Bernstein et al. (2004).