Zwicky Transient Facility Observations of Trojan Asteroids: A Thousand Colors, Rotation Amplitudes, and Phase Functions

TL;DR

This paper presents a new statistical method for analyzing sparse photometric data of asteroids, applied to Zwicky Transient Facility observations of Jupiter Trojans, providing insights into their colors, rotation, and phase functions.

Contribution

A novel likelihood-based analysis method for sparse asteroid photometry, enabling detailed characterization of Trojan asteroids from limited data.

Findings

Phase parameter correlates with asteroid color.

Trojan asteroid rotation amplitudes resemble those of main-belt asteroids.

Provided measurements for over 1000 Jupiter Trojans.

Abstract

We introduce a new method for analyzing sparse photometric data of asteroids and apply it to Zwicky Transient Facility observations of the Jupiter Trojan asteroids. The method relies on the creation of a likelihood model that includes the probability distribution of rotational brightness variations at an unknown rotation phase. The likelihood model is analyzed via a Markov Chain Monte Carlo to quantify the uncertainty in our parameter estimates. Using this method, we provide color, phase parameter, absolute magnitude and amplitude of rotation measurements for 1049 Jupiter Trojans. We find that phase parameter is correlated with color and the distribution of Trojan asteroid rotational amplitudes is indistinguishable from that of main-belt asteroids.