Astronomisches Rechen-Institut, University of Heidelberg, Moenchhofstrasse 12-14, 69120 Heidelberg, Deutschland.
Rep Prog Phys. 2013 May;76(5):056901. doi: 10.1088/0034-4885/76/5/056901. Epub 2013 Apr 19.
We review the method of exoplanetary microlensing with a focus on two-body planetary lensing systems. The physical properties of planetary systems can be successfully measured by means of a deep analysis of lightcurves and high-resolution imaging of planetary systems, countering the concern that microlensing cannot determine planetary masses and orbital radii. Ground-based observers have had success in diagnosing properties of multi-planet systems from a few events, but space-based observations will be much more powerful and statistically more complete. Since microlensing is most sensitive to exoplanets beyond the snow line, whose statistics, in turn, allow for testing current planetary formation and evolution theories, we investigate the retrieval of semi-major axis density by a microlensing space-based survey with realistic parameters. Making use of a published statistical method for projected exoplanets quantities (Brown 2011), we find that one year of such a survey might distinguish between simple power-law semi-major axis densities. We conclude by briefly reviewing ground-based results hinting at a high abundance of free-floating planets and describing the potential contribution of space-based missions to understanding the frequency and mass distribution of these intriguing objects, which could help unveil the formation processes of planetary systems.
我们回顾了系外行星微引力透镜的方法，重点介绍了二体行星透镜系统。通过对行星系统的光变曲线进行深入分析和高分辨率成像，可以成功测量行星系统的物理特性，这消除了微引力透镜无法确定行星质量和轨道半径的担忧。地面观测者已经成功地从少数几次事件中诊断出多行星系统的特性，但基于太空的观测将更加强大，统计上也更加完整。由于微引力透镜对位于雪线之外的系外行星最为敏感，而这些行星的统计数据反过来又可以检验当前的行星形成和演化理论，因此我们研究了利用基于太空的微引力透镜观测来探测半长轴密度的方法，这些观测是基于实际参数进行的。我们利用已发表的关于投影系外行星数量的统计方法（Brown 2011），发现这样的一年观测可能足以区分简单的幂律半长轴密度。最后，我们简要回顾了地面观测结果，这些结果暗示了自由漂浮行星的高丰度，并描述了基于太空的任务对理解这些有趣物体的频率和质量分布的潜在贡献，这有助于揭示行星系统的形成过程。
