The Mass Function and Galactic Distribution of Cool Planets from Microlensing

围绕其他恒星运行的行星（系外行星）的研究人员已经发现了数千个围绕各种恒星运行的行星系统。 大多数这些调查只能探测到类似于木星或更小的相对较小轨道上的行星。此外，迄今为止已知的绝大多数恒星都相对靠近太阳。 因此，人们对行星系统的外部区域知之甚少，对银河系中更远的行星的分布几乎一无所知。 当一颗遥远的星星与一个巨大的紧凑的前景物体充分对齐时，由于其引力场而使其光线发生弯曲，从而导致可观察到的放大率时，就会发生微透镜现象，可以解决这个问题。另一方面，对系外行星的微透镜调查对太阳系外部的低质量行星很敏感。 此外，微透镜对我们银河系中一系列环境中的行星很敏感。 这可能是探测自由漂浮行星是否存在的唯一方法。 这个团队将开发微透镜方法，并使用它们来确定不靠近主星星轨道的行星的性质和银河系分布。 这项工作依赖于业余天文学界的观测，该团队将组织一个国际研讨会，将业余和专业团体聚集在一起。该计划是理论和观测工作的结合，旨在开发测量大量微透镜行星样本的质量和距离的方法。 CoPI及其学生将：1）开发测量微透镜视差效应的方法，这提供了测量微透镜质量和距离的最可靠方法。 利用两次斯皮策活动总计超过900小时的结果，他们将研究所有类型的微透镜视差测量方法的现象学。(2)发展对微透镜视差效应的统一、全面的理解。 这种各种方法的综合将使视差测量成为可能，从而对行星系统的大而广泛的样本进行质量和距离估计。(3)继续领导微透镜后续网络的工作，通过监测高放大率的微透镜事件来寻找太阳系外行星。

Searches for planets orbiting other stars (exoplanets) have discovered thousands of planetary systems orbiting a wide variety of stars. Most of these surveys are only able to detect planets on relatively small orbits similar to that of Jupiter or smaller. Furthermore, the vast majority of the stars so far known to host planets are relatively close to the Sun. Therefore, little is known about the outer regions of planetary systems, and almost nothing is known about the distribution of planets farther away in the galaxy. Microlensing, which occurs when a distant star gets sufficiently aligned with a massive compact foreground object to bend its light due to its gravitational field, resulting in an observable magnification, can address this. Microlensing surveys for exoplanets, on the other hand, are sensitive to cool, low-mass planets in the outer parts of solar systems. Furthermore, microlensing is sensitive to planets in a range of environments in our Milky Way galaxy. It is perhaps the only way to detect whether free-floating planets exist. This team will develop microlensing methods and use them to determine the properties and Galactic distribution of planets that do not orbit close to a host star. This work relies on observations from the amateur astronomy community, and this team will organize an international workshop to bring the amateur and professional communities together.This program is a combination of theoretical and observational work to develop methods to measure the mass and distance to a large and broad sample of microlens planets. The CoPIs and their students will: 1) Develop methods to measure the microlens parallax effect, which provides the most robust way to measure the mass of and distance to microlenses. Using the results from two Spitzer campaigns totalling over 900 hours, they will study the phenomenology of all types of microlens parallaxes measurement methods. (2) Develop a unified, comprehensive understanding of the microlens parallax effect. This synthesis of various methods will enable parallax measurements, and thus mass and distance estimates, for a large and broad sample of planetary systems. (3) Continue to lead the Microlensing Follow Up Network effort to find extra-solar planets by monitoring high-magnification microlensing events.