# OGLE-2014-BLG-1112LB: A Microlensing Brown Dwarf Detected Through the Channel of a Gravitational Binary-Lens Event

## TL;DR

This paper reports the discovery of a brown dwarf through gravitational microlensing analysis of a binary-lens event, demonstrating the method's effectiveness in detecting faint substellar objects.

## Contribution

The study presents a new detection of a brown dwarf via microlensing, utilizing parallax and finite-source effects to measure its mass, advancing the detection techniques for dark, faint objects.

## Key findings

- Brown dwarf mass measured at (3.03 ± 0.78)×10⁻² M_sun
- Primary star has a mass of 1.07 ± 0.28 M_sun
- Projected separation is 9.63 ± 1.33 au

## Abstract

Due to the nature depending on only the gravitational field, microlensing, in principle, provides an important tool to detect faint and even dark brown dwarfs. However, the number of identified brown dwarfs is limited due to the difficulty of the lens mass measurement that is needed to check the substellar nature of the lensing object. In this work, we report a microlensing brown dwarf discovered from the analysis of the gravitational binary-lens event OGLE-2014-BLG-1112. We identify the brown-dwarf nature of the lens companion by measuring the lens mass from the detections of both microlens-parallax and finite-source effects. We find that the companion has a mass of $(3.03 \pm 0.78)\times 10^{-2}\ M_\odot$ and it is orbiting a solar-type primary star with a mass of $1.07 \pm 0.28\ M_\odot$. The estimated projected separation between the lens components is $9.63 \pm 1.33$ au and the distance to the lens is $4.84 \pm 0.67$ kpc. We discuss the usefulness of space-based microlensing observations in detecting brown dwarfs through the channel of binary-lens events.