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‧, r‧, i‧, and z‧. We use an eclipse light-curve model to fit for a precise mideclipse time and estimate the minimum separation of the two eclipsing components during the event. Our best-fit mideclipse time of {2458217.80943}-0.00050+0.00057 is 19 minutes later than the prediction of Grundy et al. The minimum separation between the center of Menoetius’s shadow and the center of Patroclus is 72.5 ± 0.7 km—slightly larger than the predicted 69.5 km. Using the derived light curves, 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 ∼0.15 mag on wide-scale surface color variability across Patroclus.
- Publication:
-
The Astronomical Journal
- Pub Date:
- May 2019
- DOI:
- 10.3847/1538-3881/ab18f4
- arXiv:
- arXiv:1904.06379
- Bibcode:
- 2019AJ....157..203W
- Keywords:
-
- minor planets;
- asteroids: individual: Patroclus;
- planets and satellites: surfaces;
- techniques: photometric;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 5 pages, 3 figures, accepted for publication in AJ