0 Assigned ID: 6866 ----- Attempting Submission 1 (Thu Apr 10 23:47:21 GMT 2025) ----- Solar System Small Bodies provide direct insight into the formation and evolution of the solar system and to planet formation in general. Of particular value are Outer Solar System Binaries (OSSBs) since they encode information about a variety of planetesimal formation processes like the Streaming Instability, collisional evolution, and dynamical stirring. HST has invested a significant amount of solar system observations to discovering these binaries, but almost no effort has been devoted to measuring the observational biases to determine the true underlying frequency of OSSB binaries. Without information on the binary fraction as a function of size, dynamical class, and other properties, many important questions about planet formation are left unanswered. In this Archival proposal, we will characterize the Detection Probability of over 500 outer solar system small bodies observed with HST. Using the same pipeline on real and injected objects minimizes biases and allows a "Binary Survey Simulator" to leverage hundreds of non-detections to rigorously test binary population models. Bayesian parameter inference on binary population statistics (like frequency as a function of size, orbit and relative brightness) will finally provide OSSB population models. This enables a variety of investigations but we focus on three major questions related to differences between Trojans, Centaurs, Cold TNOs, and Hot TNOs that inform specific planet formation processes. This project maximally leverages HST's unique archival dataset to answer open questions in planet formation. Since it uses only HST archival data, it is ideally and uniquely suited for Archival Program support. PI Ragozzine is an expert in TNO binaries (e.g., Ragozzine & Brown 2009, Ragozzine et al. 2024) and has been PI of several binary HST proposals. He has detailed expertise in the orbital dynamics, Bayesian parameter inference, and population modeling. For example, he is a major co-author on the exoplanet-based Planetary System Simulator (SysSim, He et al. 2020). Co-I Grundy is a major expert in HST data reduction and analysis for TNBs. He has led several programs focusing on characterization of individual TNB systems. He maintains an extensive online catalog of TNBs. Co-I Proudfoot has extensive experience in modeling TNO binaries, Bayesian parameter inference, and population modeling. He helped develop the nPSF tool that forms the basis of our search tool. Co-I Spencer has experience in TNO binaries, Bayesian parameter inference, and PSF fitting. He is also separately funded to develop a similar binary population model for wide binaries detected in the DEEP survey. Solar System Astronomy 0 false false false false false false false SUPPORTED