OGLE-2013-BLG-0102LA,B: Microlensing binary with components at star/brown-dwarf and brown-dwarf/planet boundaries

TL;DR

This paper analyzes a gravitational microlensing event revealing a binary system with components near the star/brown-dwarf and brown-dwarf/planet mass boundaries, providing detailed physical parameters of the system.

Contribution

The study presents a detailed analysis of a microlensing event that identifies a binary system with components at the star/brown-dwarf and brown-dwarf/planet boundaries, including their masses and separation.

Findings

Masses near hydrogen and deuterium-burning limits

Distance to lens system approximately 3 kpc

Projected separation about 0.8 AU

Abstract

We present the analysis of the gravitational microlensing event OGLE-2013-BLG-0102. The light curve of the event is characterized by a strong short-term anomaly superposed on a smoothly varying lensing curve with a moderate magnification $A_{\rm max}\sim 1.5$. It is found that the event was produced by a binary lens with a mass ratio between the components of $q = 0.13$ and the anomaly was caused by the passage of the source trajectory over a caustic located away from the barycenter of the binary. From the analysis of the effects on the light curve due to the finite size of the source and the parallactic motion of the Earth, the physical parameters of the lens system are determined. The measured masses of the lens components are $M_{1} = 0.096 \pm 0.013~M_{\odot}$ and $M_{2} = 0.012 \pm 0.002~M_{\odot}$, which correspond to near the hydrogen-burning and deuterium-burning mass limits, respectively. The distance to the lens is $3.04 \pm 0.31~{\rm kpc}$ and the projected separation between the lens components is $0.80 \pm 0.08~{\rm AU}$.