Extreme mass ratio multiple stellar systems: understanding the origin of the brown dwarf desert and directly imaged planets

该奖项资助了一个观测项目，以确定大质量恒星（质量为太阳3-8倍的恒星）的近距离、非常低质量恒星伴星的频率。该结果将用于测试恒星形成过程的物理极限，并更好地了解所谓的“褐矮星沙漠”现象的存在，该现象用于描述双星约3-5个天文单位（AU）内褐矮星的稀缺性，并在行星和恒星形成模型中发挥重要作用。AU是一个长度单位，大约等于地球和太阳之间的距离。研究结果将用于测试恒星形成模型，以及在棕矮星和系外行星搜索中发现的次恒星伴星的性质。它们还将为太阳系外行星（围绕其他恒星运行的行星）成像调查提供有用的背景。PI将指导并指导两名本科生在此项目中进行研究实习。为了完成这项工作，研究人员将在利克天文台的ShaneAO仪器和双子座行星成像仪上使用极端自适应光学系统，以测量极端质量比双星系统的数量。该项目将包括两种类型的目标：一种来自1 kpc内小于100 Myr的丰富年轻星团，另一种来自与星团无关的野星。对大质量恒星图像去除了点扩展函数后，数据进行简化后，可以识别出微弱的伴星。

This award funds an observational program to determine the frequency of close, very low-mass stellar companions to massive stars (those with 3-8 times the mass of the Sun). The results will be used to test the physical limit of the star formation process and to better understand the existence of the so-called "brown dwarf desert" phenomenon, which is used to describe the scarcity of brown dwarfs within about 3-5 astronomical units (AU) of binary stars, and plays a large role in planetary and star formation models. The AU is a unit of length approximately equal to the distance between the Earth and Sun. The results will be used to test star formation models and the nature of sub-stellar companions discovered in brown dwarf and exoplanet searches. They will also provide useful context for extrasolar planet (planets that orbit other stars) imaging surveys. The PI will supervise and mentor two undergraduate students with research internships on this project.To accomplish this work, the researchers will use extreme adaptive optics systems with the ShaneAO instrument at the Lick Observatory and the Gemini Planet Imager in order to measure the number of extreme mass-ratio binary star systems. The project will comprise two types of targets: one from rich young star clusters within 1 kpc and less than 100 Myr, and another from field stars unassociated with clusters. After the data are reduced, faint companions will be identified from the data after point-spread-functions have been removed from the images of the high-mass stars.