First Science with LSST: The Rubin Outer Solar System Model

The NSF-DOE Vera C. Rubin Observatory, which completed construction and commissioning in October 2025, is the U.S. National Science Foundation’s new flagship astronomical survey facility housing the 8m-class Simonyi Survey Telescope and the 3.2 Gigapixel camera (DOE LSSTCam). The Legacy Survey of Space and Time (LSST) began in early 2026, delivering an unprecedentedly comprehensive census of small bodies of the Solar System, one of its key science goals. The LSST will deliver the largest dataset of Solar System objects to date and will discover approximately 5.2 million asteroids (3.5 times more than are currently known), including 37,000 objects beyond Neptune. This project will produce a fully calibrated and debiased catalog and model (the number density distribution as a function of size, color, and orbital elements) of the outer Solar System. The delivered model will place strong observational constraints to theoretical models of solar system formation and evolution. As part of the project, the researchers will contribute to increasing STEM participation through undergraduate project-based learning opportunities and will directly engage with the public through planetarium shows and Asteroid Day, a global program of awareness of asteroid science. This well characterized catalog, together with a fully debiased population model, would become the standard observational reference for the next decade of theoretical studies, enabling the probing of the effects of planetesimal formation over a wide range of diameters, and across all distant Solar System populations. Many of the hypotheses that attempt to explain the formation and evolution of our Solar System rely on the fact that the current distribution (dynamical and physical) of populations in the trans-Neptunian Object (TNO) region was shaped by major events in the early Solar System. This project will use the catalog to analyze the structure of the TNO region and search for the most distant objects in our Solar System, including any undiscovered planetary-sized objects. The project will make the first truly statistically robust test of how—and how violently—the outer Solar System was sculpted. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.