Modeling the Performance of the LSST in Surveying the Near-Earth Object Population

Abstract

We have performed a detailed survey simulation of the LSST performance with regards to near-Earth objects (NEOs) using the project's current baseline cadence. The survey shows that if the project is able to reliably generate linked sets of positions and times (a so-called "tracklet") using two detections of a given object per night and can link these tracklets into a track with a minimum of 3 tracklets covering more than a ∼ 12 day length-of-arc, they would be able to discover 62% of the potentially hazardous asteroids (PHAs) larger than 140 m in its projected 10 year survey lifetime. This completeness would be reduced to 58% if the project is unable to implement a pipeline using the two detection cadence and has to adopt the four detection cadence more commonly used by existing NEO surveys. When including the estimated performance from the current operating surveys, assuming these would continue running until the start of LSST and perhaps beyond, the completeness fraction for PHAs larger than 140 m would be 73% for the baseline cadence and 71% for the four detection cadence. This result is a lower completeness than the estimate of Ivezić et al. (2007) and Ivezic et al. (2014); however the result is quite close to that of Jones et al. (2016) who show completeness ∼ 70% using the identical survey cadence as used here. We show that the traditional method of using absolute magnitude H < 22 mag as a proxy for the population with diameters larger than 140m results in completeness values that are too high by ∼ 5%. Our simulation makes use of the most recent models of the physical and orbital properties of the NEO and PHA populations, as well as simulated cadences and telescope performance estimates provided by the LSST project. The consistency of the results presented here when compared to those of Jones et al. (2016) demonstrates the robustness of these survey modeling approaches. We also show that while neither LSST nor a space-based IR platform like NEOCam individually can complete the survey for 140m diameter NEOs, the combination of these systems can achieve that goal after a decade of observation.

Statistical analysis of astrometric errors for the most productive asteroid surveys

“…According to NEO population models (Harris and D'Abramo, 2015), we have reached an estimated discovery completeness of 95% for NEOs larger than 1 km NEOs and of 30% for NEOs larger 140 m. In the near future, LSST (Jones et al, 2016) and possibly NEOCAM (Grav et al, 2016) will increase the number of known asteroids by an order of magnitude.…”

The future of planetary defense

“…To this end, telescopes with improved sensitivity over the current surveys are required. Without such an increase in capability, it will take many decades for the current suite of surveys to find and catalog 90% of the NEOs larger than 140 m [ Mainzer et al ., ; Grav et al ., ].…”

What can space resources do for astronomy and planetary science?

“…So the first robotic mining forays can begin around 2030. from these surveys. When the Large Synoptic Survey Telescope (LSST) comes on-line in the early 2020s it will find many more near-Earth asteroids [21]. Many of these nearEarth asteroids will be small and must have orbits bringing them especially close to the Earth just to be detected.…”

“…For example, an optical interferometer that can resolve the inner workings of quasars, and image continents and oceans on twins of the Earth orbiting other stars is an idea that has already been studied. It was called the "Terrestrial Planet Imager -Interferometer" (Figure 5), but it has been set aside since 2008 21 . We know how to build it conceptually, but it exceeds today's construction capabilities in space, and we can't afford it at current prices.…”

“…What can we do to ensure that ever greater observatories lie ahead? The new large space telescopes now being discussed will not launch for [15][16][17][18][19][20][21][22][23][24][25] years. On that timescale much is going to change that could help our field.…”