Recoverability of known near-Earth asteroids

This paper analyzes the current population of known near-Earth asteroids (NEAs) and presents statistics on the recoverability of NEAs with both targeted observation campaigns and all-sky surveys. For an asteroid to be observable at a future apparition, given the right geometry, the plane-of-sky uncertainty must be small enough to be covered by a telescope's eld of view and the asteroid must be brighter than the detector's limiting magnitude. Since recoverability is a telescope-dependent property, we select two representative instruments that span a wide range of capability and availability: the 1.0- meter I52 telescope of the Catalina Sky Survey and the Hyper Suprime-Cam of the 8.2-meter Subaru telescope. Based on this choice, we classify asteroids as recoverable, potentially recoverable, and not recoverable depending on whether they could be detected with an I52-class telescope, only with a Subaru-class telescope, or with neither, respectively. Using these denitions, we nd that the majority (90%) of NEAs with H < 22 and most (93%) potentially-hazardous asteroids (PHAs) are recoverable or potentially recoverable in the next 50 years. When considering fainter asteroids down to H 28, about two thirds of the NEA population and half of the low-MOID asteroids (MOID 0:05 au) are either recoverable or potentially recoverable. As of 2019-Oct-13, the Sentry risk list includes 193 objects with an impact probability greater than 10􀀀6 that are not recoverable. The fraction of NEAs and low-MOID NEAs that are not recoverable can be reduced by up to 47% and 43%, respectively, when incorporating statistical estimates of serendipitous recoveries by all-sky surveys.