2001/07/27 by Cheongho Han · 1 citation
Physics and Astronomy · #Astronomy and Astrophysical Research #Binary number #Degeneracy (biology) #Exoplanet #Gravitational lens #Gravitational microlensing #Light curve #Perturbation (astronomy) #Planet #Planetary system #Scientific Research and Discoveries #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/324338
published as CBNU-PHYS-52/2001 · total 5 pages, including 1 figure and no table, ApJ, submitted, better quality pdf file is avalilable at http://astroph.chungbuk.ac.kr/~cheongho/publication.html
arxiv created 2001/07/27 · openalex publication_date 2002/01/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
An extrasolar planet can be detected by microlensing because the planet can perturb the smooth lensing light curve created by the primary lens. However, it was shown by Gaudi that a subset of binary-source events can produce light curves that closely resemble those produced by a significant fraction of planet/star lens systems, causing serious contamination of samples of suspected planetary systems detected via microlensing. In this paper, we show that if a lensing event is observed astrometrically, one can unambiguously break the photometric degeneracy between the binary-source and the planetary lensing perturbations. This is possible because while the planet-induced perturbation in the trajectory of the lensed source image centroid shifts points away from the opening of the unperturbed elliptical trajectory, the perturbation induced by the binary-source companion always points toward the opening. Therefore, astrometric microlensing observations using future high-precision interferometers will be important for solid confirmation of microlensing planet detections.