Determination of 1929 Asteroid Rotation Periods from WISE Data

TL;DR

This study analyzed WISE infrared data of 4420 asteroids to determine their rotation periods, successfully estimating periods for 1929 objects with high accuracy and comparing results to a control group.

Contribution

It introduces a method for extracting asteroid rotation periods from WISE data using Fourier analysis and evaluates solution accuracy against a control set.

Findings

88% of best-fit solutions are accurate within 5%

Aliasing suppression is more effective with non-uniform sampling

Three main solutions capture most rotational frequencies

Abstract

We used 22 $\mu$m (W4) Wide-field Infrared Survey Explorer (WISE) observations of 4420 asteroids to analyze lightcurves and determined spin period estimates for 1929 asteroids. We fit second-order Fourier models at a large number of trial frequencies to the W4 data and analyzed the resulting periodograms. We initially excluded rotational frequencies exceeding 7.57 rotations per day (P < 3.17 hr), which are not sampled adequately by WISE, and periods that exceed twice the WISE observation interval, which is typically 36 hr. Three solutions accurately capture the vast majority of the rotational frequencies in our sample: the best-fit frequency and its mirrors around 3.78 and 7.57 rotations per day. By comparing our solutions to a high-quality control group of 752 asteroid spin periods, we found that one of our solutions is accurate (within 5%) in 88% of the cases. The best-fit, secondary, and tertiary solutions are accurate in 55%, 27%, and 6% of the cases, respectively. We also observed that suppression of aliased solutions was more effective with non-uniform sampling than with quasi-uniform sampling.