Diving DEEP into the Kuiper Belt: Dynamical Analysis of Newly Discovered TNOs

The DECam Ecliptic Exploration Project (DEEP) was an NOAO/NOIRLab survey program that was allocated 47.5 nights from 2019-2023 to carry out a very deep survey for trans-Neptunian objects (TNOs). We reached a survey depth of around VR~26.8 through combining four hours of images with digital tracking (also known as shift and stack). Results to date are presented in a series of papers: Paper I (survey design; Trilling et al. 2024); Paper II (observational strategy; Trujillo et al. 2024); Paper III (survey simulation; Bernardinelli et al. 2024); Paper IV (shapes of TNOs in single exposures; Strauss et al. 2024); Paper V (brightness distribution of faint cold classical TNOs; Napier et al. 2024); Paper VI (orbits of a subset of DEEP objects; Smotherman

et al. 2024); and Paper VII (strengths of several super-fast rotating asteroids; Strauss et al. 2024b). Several more papers are in preparation. A summary of the efficacy of the DEEP program in comparison to other TNO surveys is shown in Figure 1 (Trilling et al. 2024).

Here we present the status of the processing of the full dataset, which is near completion. We have processed all DEEP images consistently using the LSST Science Pipelines, with the inclusion of injected sources across the full magnitude range accessible to the survey, as well as with the inclusion of resolved binary sources that allow us to test our performance in identifying such TNOs. We have studied multiple imaging differencing strategies to optimize their completeness vs magnitude for moving object identification, pushing our data towards fainter magnitudes, as well as applied multiple shift-and-stack and linking approaches, thus allowing us to reach our predicted yield of thousands of TNOs.

Additionally, studying the orbital architecture of the TNO populations offers critical insights into Solar System formation and evolution, shedding light on processes such as accretion, planetary migration, and the possible existence of yet-undiscovered planets. Increasing the catalog of known TNOs and studying the dynamical patterns present in the known population is therefore a high priority of the planetary science community. Using the Small Body Dynamics Tool (SBDynT), we produce a preliminary dynamical analysis of the new TNOs discovered by DEEP, including resonance occupation identification and proper orbital elements.  This expanded catalog of objects and their dynamical properties enables a more comprehensive comparison with known TNO distributions, potentially offering new constraints on the formation and migration history of the outer Solar System. These calculated proper elements and mean motion resonance classifications of the DEEP survey objects demonstrate the importance of systematic dynamical studies in guiding future observational efforts, particularly in the era of large-scale surveys such as the Vera C. Rubin Observatory’s LSST. The code used to complete the study, SBDynT, is publicly available on GitHub (SBDynT; https://github.com/small-body-dynamics/SBDynT). Development of SBDynT is supported by NASA PDART grant 80NSSC23K0886.