The Characterization and Discovery of Solar System Small Bodies in Modern Astronomical Surveys

Abstract

Starting in 2024, the Vera C. Rubin Observatory will conduct a comprehensive survey of the night sky named the Legacy Survey of Space and Time (LSST). LSST will observe the Southern sky every three nights continuously for ten years and is predicted to discover six million new minor planets. Claims in the literature have suggested that optically-derived diameters from such surveys are only accurate to within 50% compared to IR-based estimates. Using “Asteroid Thermal Modeling” (ATM), we show that optical measurements can be used to constrain asteroid diameters with 0.4% bias and scatter of only 17%. LSST will discover minor planets by observing “tracklets”: intranight linkages of two or more observations. The requirement to observe tracklets places a strong constraint on cadence and makes datasets not constructed with such a cadence unsuitable for discovery searches. We present “Tracklet-less Heliocentric Orbit Recovery” (THOR), a cadence-independent discovery algorithm that does not require tracklets. We apply THOR to two weeks of observations from the Zwicky Transient Facility (ZTF) and show that it can recover 1.5-2x as many asteroids as its tracklet-based counterparts. We describe our efforts to deploy THOR on the Asteroid Discovery, Analysis, and Mapping (ADAM) platform – the beginnings of a cloud-based discovery service which we name ADAM::THOR. We use the prototype service to search 0.2% of the exposures contained in the NOIRLab Source Catalog and discover 104 new minor planets.