Multiband photometry of a Patroclus-Menoetius mutual event: Constraints on surface heterogeneity

Abstract

We present the first complete multiband observations of a binary asteroid mutual event. We obtained high-cadence, high-signal-to-noise photometry of the UT 2018 April 9 inferior shadowing event in the Jupiter Trojan binary system Patroclus-Menoetius in four Sloan bands $-$ $g^{\prime }$, $r^{\prime }$, $i^{\prime }$, and $z^{\prime }$. We use an eclipse lightcurve model to fit for a precise mid-eclipse time and estimate the minimum separation of the two eclipsing components during the event. Our best-fit mid-eclipse time of $2458217.80943_{-0.00050}^{+0.00057}$ is 19 minutes later than the prediction of Grundy et al. (2018); the minimum separation between the center of Menoetius' shadow and the center of Patroclus is $72.5\pm 0.7$ km $-$ slightly larger than the predicted 69.5 km. Using the derived lightcurves, we find no evidence for significant albedo variations or large-scale topographic features on the Earth-facing hemisphere and limb of Patroclus. We also apply the technique of eclipse mapping to place an upper bound of $\sim$0.15 mag on wide-scale surface color variability across Patroclus.

5 pages, 3 figures, accepted for publication in AJ

References in corpus (5)

• The Correlated Colors of Transneptunian Binaries
• A hypothesis for the color bimodality of Jupiter Trojans
• Taxonomy of asteroid families among the Jupiter Trojans: Comparison between spectroscopic data and the Sloan Digital Sky Survey colors
• The differing magnitude distributions of the two Jupiter Trojan color populations
• The Upcoming Mutual Event Season for the Patroclus - Menoetius Trojan Binary

Cited by in corpus (3)

• JWST near-infrared spectroscopy of the Lucy Jupiter Trojan flyby targets: Evidence for OH absorption, aliphatic organics, and CO${}_2$
• 2021 occultations and transits of Linus orbiting (22) Kalliope: I. Polygonal and `cliptracing' algorithm
• Evidence of Possible Spectral Variability in the Patroclus-Menoetius Binary System