Probing Circumstellar Envelopes with Gravitational Microlensing

在这个项目中，将发展一种理论基础和观测方法，用于解释在正在进行的监测活动过程中发现的恒星引力微透镜事件。 当一个看不见但质量巨大的物体从观测者和背景星星之间经过时，这样的事件原则上可以用来“引力成像”，否则无法分辨恒星的光球和星周结构。 目前的微透镜技术只有在假设恒星光球正常对称的情况下才有用。 PI将扩展该技术，以包括涉及红巨星的微透镜事件。 后者具有高度不对称的大气结构，风，以及信封大小，速度和密度的变化。 这项技术的发展也可能是有用的分类在其他附近的正常星系，如M31和活动星系核的核透镜事件。该项目的资金由美国国家科学基金会的恒星天文天体物理学计划（AST/SAA）提供。

ABSTRACTIgnace, Richard"Probing Circumstellar Envelopes with Gravitational Microlensing"AST-9986915In this project a theoretical basis and observational methodology will be developed for interpreting stellar gravitational microlensing events that are discovered in the course of ongoing monitoring campaigns. Such events in principle can be used to 'gravitationally image' otherwise unresolvable stellar photospheric and circumstellar structures when an invisible but massive object passes between the observer and a background star. Current microlensing techniques are useful only by assuming normal symmetrical stellar photospheres. The PIs will extend the technique to include microlensing events that involve red giant stars. The latter have highly asymmetrical atmospheric structure, winds, and variations in envelope size, velocity and density. The technique developed also may be useful in categorizing lensing events in the nuclei of other nearby normal galaxies such as M31 and active galactic nuclei.Funding for this project was provided by the NSF program for Stellar Astronomy & Astrophysics (AST/SAA).