# OGLE-2016-BLG-1469L: Microlensing Binary Composed of Brown Dwarfs

## TL;DR

This paper reports the discovery and analysis of a binary system of two brown dwarfs using microlensing, measuring their masses, distance, and separation, and demonstrating microlensing's effectiveness in detecting such binaries.

## Contribution

First microlensing detection of a brown-dwarf binary with finite-source and parallax effects enabling precise mass and separation measurements.

## Key findings

- Measured masses: 0.05 and 0.01 solar masses
- Distance to the system: approximately 4.5 kpc
- Projected separation: about 0.33 au

## Abstract

We report the discovery of a binary composed of two brown dwarfs, based on the analysis of the microlensing event OGLE-2016-BLG-1469. Thanks to detection of both finite-source and microlens-parallax effects, we are able to measure both the masses $M_1\sim 0.05\ M_\odot$, $M_2\sim 0.01\ M_\odot$, and distance $D_{\rm L} \sim 4.5$ kpc, as well as the projected separation $a_\perp \sim 0.33$ au. This is the third brown-dwarf binary detected using the microlensing method, demonstrating the usefulness of microlensing in detecting field brown-dwarf binaries with separations less than 1 au.