OGLE-2016-BLG-0613LABb: A Microlensing Planet in a Binary System

TL;DR

This paper analyzes a microlensing event revealing a planetary companion in a binary system, exploring multiple solutions and predicting future observations to distinguish system configurations.

Contribution

It identifies a planetary companion in a binary lens system with four degenerate solutions, advancing understanding of complex microlensing events.

Findings

The planetary companion is a super-Jupiter.

Multiple degenerate solutions exist for the system configuration.

Future proper motion measurements will clarify the binary's nature.

Abstract

We present the analysis of OGLE-2016-BLG-0613, for which the lensing light curve appears to be that of a typical binary-lens event with two caustic spikes but with a discontinuous feature on the trough between the spikes. We find that the discontinuous feature was produced by a planetary companion to the binary lens. We find 4 degenerate triple-lens solution classes, each composed of a pair of solutions according to the well-known wide/close planetary degeneracy. One of these solution classes is excluded due to its relatively poor fit. For the remaining three pairs of solutions, the most-likely primary mass is about $M_1\sim 0.7\,M_\odot$ while the planet is a super-Jupiter. In all cases the system lies in the Galactic disk, about half-way toward the Galactic bulge. However, in one of these three solution classes, the secondary of the binary system is a low-mass brown dwarf, with relative mass ratios (1 : 0.03 : 0.003), while in the two others the masses of the binary components are comparable. These two possibilities can be distinguished in about 2024 when the measured lens-source relative proper motion will permit separate resolution of the lens and source.