The Vera Rubin Observatory's Legacy Survey of Space and Time (LSST) is expected to begin survey operations in mid-to-late 2025. Over ten years, it will repeatedly map the southern sky in six photometric bands to a depth of LSST is expected to discover the largest catalog of solar system objects to date – many times more objects than are currently known.
We use Sorcha (Meritt et al., in prep), a new solar system survey simulator, to simulate ten years of LSST detections of trans-Neptunian objects (TNOs). We report the expected TNO yield of the survey under different assumptions of state-of-the-art orbital, size, color, and light curve distributions, and provide an update to the 2009 LSST Science Book predictions. We discuss the number of objects discoverable given LSST linking requirements as well as the shortcomings of this strategy.
We find that TNOs will be discovered very early in the ten-year survey, with a majority discovered by the end of year 2. We present the expected end-of-survey completeness on TNOs as a function of absolute magnitude, as well as distributions of per-band detection numbers and orbital arc lengths. Given these distributions, we discuss the recovery of light curves and phase curve fits per band. Comparing these predictions to actual LSST discoveries, along with a calibrated survey selection function, will allow the rejection of this or other TNO models and prompt the development of new population models.
An early version of our simulations are available to the LSST community on the Rubin Science Platform as Data Preview 0.3.