Microlensing Detections of Planets in Binary Stellar Systems

TL;DR

This paper shows that microlensing can effectively detect planets within binary star systems, especially for certain binary configurations and planet masses, expanding the known parameter space beyond other methods.

Contribution

It introduces a novel microlensing technique for detecting planets in binary systems, including low-mass planets and specific binary separations.

Findings

Microlensing can detect planets down to 0.1 Jupiter masses in binaries.

Optimal detection occurs when the secondary star is within a specific range depending on the planet.

The method covers parameter spaces not accessible by other detection techniques.

Abstract

We demonstrate that microlensing can be used for detecting planets in binary stellar systems. This is possible because in the geometry of planetary binary systems where the planet orbits one of the binary component and the other binary star is located at a large distance, both planet and secondary companion produce perturbations at a common region around the planet-hosting binary star and thus the signatures of both planet and binary companion can be detected in the light curves of high-magnification lensing events. We find that identifying planets in binary systems is optimized when the secondary is located in a certain range which depends on the type of the planet. The proposed method can detect planets with masses down to one tenth of the Jupiter mass in binaries with separations <~ 100 AU. These ranges of planet mass and binary separation are not covered by other methods and thus microlensing would be able to make the planetary binary sample richer.