Predicting the Accuracy of Asteroid Size Estimation with Data from the Rubin Observatory Legacy Survey of Space and Time

TL;DR

This paper evaluates the potential of LSST optical data to estimate asteroid sizes with about 15% accuracy, improving previous models and demonstrating the value of modern survey photometry.

Contribution

The study introduces advanced data-driven models for asteroid size estimation using SDSS and LSST data, quantifying the impact of photometric errors on size accuracy.

Findings

LSST data can achieve ~15% asteroid size accuracy.

Optical size estimates are only 1.3-1.4 times less accurate than WISE.

Modern digital sky surveys enable more precise optical asteroid measurements.

Abstract

Recent work has shown that the correlation between SDSS colors and optical albedo can be used to estimate asteroid sizes from optical data alone. We revisit a correlation between SDSS colors and optical albedo for asteroids, with the albedo derived using WISE-based size estimates. Moeyens, Myhrvold \& Ivezi\'{c} (2020) showed that this correlation can be used to estimate asteroid sizes with optical data alone, with a precision of about 17\% relative to WISE-based size estimates. We present here several more sophisticated data-driven models for the variation of optical albedo with colors and estimate the contribution of SDSS photometric errors to the albedo and size estimate uncertainties. We use the results of our analysis to predict that LSST data will enable asteroid size precision of about 15\% relative to WISE-based size estimates. Compared to the accuracy of WISE-based size estimates of 15-20\%, the implied accuracy of optical size estimates, in the range 21-25\%, is thus only a factor of 1.3 to 1.4 worse. This size estimation accuracy is significantly better than commonly assumed for optical data and is due to accurate and homogeneous multi-band photometry delivered by modern digital sky surveys.