1999/12/02 by Sun Hong Rhie, David P. Bennett, Rhie, Sun Hong +2 · 1 citation
Environmental Science · Physics and Astronomy · #Adaptive optics and wavefront sensing #Astrophysics (astro-ph) #FOS: Physical sciences #Impact of Light on Environment and Health #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9912050
14 pages, 8 figures
arxiv created 1999/12/02 · openalex publication_date 1999/12/02 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In a line caustic crossing microlensing event, the caustic line moving across the surface of the source star provides a direct method to measure the integrated luminosity profile of the star. Combined with the enormous brightening at the caustic crossings, microlensing offers a promising tool for studying stellar luminosity profiles. We derive the amplification behavior of the two extra images that become partial images conjoined across the critical curve at a line caustic crossing. We identify the multiplicative factors that depend on the caustic crossing point and the relative size of the star, and the shape function that depends on the stellar luminosity profile. We examine the analytic limb-darkening models -- linear, square root, and square -- using the analytic form of the shape function. We find that the microlensing lightcurves must be determined to an accuracy of better than 0.3-0.8% in order to be able to determine the linear limb-darkening parameter c1 with precision of δc1 = 0.1. This is similar to the accuracy level required in eclipsing binaries as reported by Popper (1984).