Studying wave optics in the light curve of exoplanet microlensing

TL;DR

This paper explores the wave optics effects in gravitational microlensing by binary systems, proposing that diffraction patterns can reveal additional exoplanet information, especially with long-wavelength observations like SKA.

Contribution

It introduces the concept of wave optics in binary microlensing and discusses the potential for detecting diffraction effects to enhance exoplanet studies.

Findings

Wave optics effects can produce observable diffraction patterns in microlensing.

Coherent pair images may form during caustic crossings, enabling wave optics detection.

Long-wavelength observations can provide new insights into exoplanet parameters.

Abstract

We study the wave optics features of gravitational microlensing by a binary lens composed of a planet and a parent star. In this system, the source star near the caustic line produces a pair of images in which they can play the role of secondary sources for the observer. This optical system is similar to the Young double-slit experiment. The coherent wave fronts from a source on the lens plane can form diffraction pattern on the observer plane. This diffraction pattern has two modes from the close- and wide-pair images. From the observational point of view, we study the possibility of detecting this effect through the Square Kilometer Array (SKA) project in the resonance and high magnification channels of binary lensing. While the red giant sources do not seem satisfy the spatial coherency condition, during the caustic crossing, a small part of source traversing the caustic line can produce coherent pair images. Observations of wave optics effect in the longer wavelengths accompanied by optical observations of a microlensing event provide extra information from the parameter space of the planet. These observations can provide a new basis for study of exoplanets.