Predictions of the LSST Solar System Yield: Discovery Rates and Characterizations of Centaurs

Abstract

The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will start by the end of 2025 and operate for 10 yr, offering billions of observations of the southern night sky. One of its main science goals is to create an inventory of the solar system, allowing for a more detailed understanding of small-body populations, including the Centaurs, which will benefit from the survey's high cadence and depth. In this paper, we establish the first discovery limits for Centaurs throughout the LSST's decade-long operation using the best available dynamical models. Using the survey simulator Sorcha, we predict a roughly 7-fold increase in Centaurs in the Minor Planet Center (MPC) database, reaching similar to 1200-2000 (dependent on definition) by the end of the survey- about 50% of which are expected within the first 2 yr. Approximately 30-50 Centaurs will be observed twice as frequently, as they fall within one of the LSST's Deep Drilling Fields (DDF) for on average only up to 2 months. Outside of the DDFs, Centaurs will receive similar to 200 observations across the ugrizy filter range, facilitating searches for cometary-like activity through point-spread function extension analysis, as well as fitting light curves and phase curves for color determination. Regardless of definition, over 200 Centaurs will achieve high-quality color measurements across at least three filters in the LSST's six filters. These observations will also provide over 300 well-defined phase curves in the griz bands, improving absolute magnitude measurements to a precision of 0.2 mag.