A Survey of Nearby Very Low Mass Star-Brown Dwarf Spectral Binaries

对附近极低质量星棕矮星光谱双星的调查

• 批准号: 1517177
• 负责人: Adam Burgasser
• 金额: $ 20.52万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2020-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1517177&HistoricalAwards=false
• 关键词: Survey; Nearby; Very; Low; Mass

The coolest stars and brown dwarfs, with mass less than 10% that of the Sun, compose the majority population in the Milky Way Galaxy. It is not yet clear how these objects were formed. An accurate measurement of the fraction of low-mass stars that are actually systems of two or more stars can constrain or rule out several currently proposed theories. The proposal team has developed a method to identify short-period, low-mass multiple systems. They will determine the low-mass multiple frequency, and for some binary systems they will measure their orbital properties and masses. The program will specifically engage students historically underrepresented in science fields. Analysis tools will be constructed in a manner that facilitates participation by high school and undergraduate research students in stellar research, with a focus on engaging students from historically underrepresented groups in science.The program's primary goal is to measure the very low mass (M 0.1 Msun) binary fraction by determining a volume-limited and bias-corrected multiplicity fraction of "spectral blend" binaries, systems identified by their combined-light spectroscopy. It involves four primary investigations: (1) a near-infrared spectral survey of M7-L5 dwarfs within 25 pc of the Sun, (2) analysis of these spectra to identify and characterize blended light pairs; (3) numerical simulations to determine the selection function and its dependence on population age and mass distributions; and (4) multi-component radial and astrometric monitoring observations, with full orbital coverage of five previously identified binaries, to measure orbits, individual component masses and spin-orbit alignment. The data collected and analysis tools developed in this program willm be made publicly available through the SpeX Prism Library and Virtual Observatory frameworks for scientific investigations by the larger community.

最冷的恒星和褐矮星，质量不到太阳的10%，构成了银河系的大多数人口。 目前还不清楚这些物体是如何形成的。精确测量实际上是两颗或更多恒星系统的低质量恒星的比例可以限制或排除目前提出的几个理论。该提案小组已经开发出一种方法来识别短周期，低质量的多系统。他们将确定低质量的多频，对于一些双星系统，他们将测量它们的轨道特性和质量。该计划将专门吸引历史上在科学领域代表性不足的学生。分析工具的构建方式将有利于高中和本科研究生参与恒星研究，重点是吸引来自历史上代表性不足的科学群体的学生。（M 0.1 Msun）双星分数，通过确定“光谱混合”双星的体积限制和偏差校正的多重性分数，通过它们的组合光光谱识别系统。它包括四个主要的研究：（1）对距离太阳25秒差距以内的M7-L5矮星进行近红外光谱测量，（2）分析这些光谱以识别和表征混合光对，（3）数值模拟以确定选择函数及其对星群年龄和质量分布的依赖性;和（4）多分量径向和天体测量监测观测，对先前确定的五个双星进行全轨道覆盖，以测量轨道、单个分量质量和自旋-轨道对准。 该计划中收集的数据和开发的分析工具将通过SpeX Prism图书馆和虚拟天文台框架公开提供，供更大的社区进行科学调查。