Binary Source Microlensing Event OGLE-2016-BLG-0733: Interpretation of A Long-term Asymmetric Perturbation

TL;DR

This paper analyzes a microlensing event with a long-term asymmetric perturbation, revealing it was caused by a binary source rather than a planet, highlighting the importance of careful interpretation in planet detection.

Contribution

It demonstrates that binary sources can mimic planetary signals in microlensing events, emphasizing the need for detailed modeling and high-cadence observations.

Findings

Binary sources can produce long-term asymmetric perturbations.

High-cadence observations are crucial for accurate interpretation.

Proper modeling distinguishes between planetary and binary source signals.

Abstract

In the process of analyzing an observed light curve, one often confronts various scenarios that can mimic the planetary signals causing difficulties in the accurate interpretation of the lens system. In this paper, we present the analysis of the microlensing event OGLE-2016-BLG-0733. The light curve of the event shows a long-term asymmetric perturbation that would appear to be due to a planet. From the detailed modeling of the lensing light curve, however, we find that the perturbation originates from the binarity of the source rather than the lens. This result demonstrates that binary sources with roughly equal-luminosity components can mimic long-term perturbations induced by planets with projected separations near the Einstein ring. The result also represents the importance of the consideration of various interpretations in planet-like perturbations and of high-cadence observations for ensuring the unambiguous detection of the planet.