Ultracool Astrophysics from Substellar Binaries

在这个项目中，刘博士和他的研究小组将对已知最冷的褐矮星进行深入，敏感的搜索，以确定适合动态质量测定的新的亚恒星双星，并搜索比目前已知的任何东西都冷的自由漂浮物体。 他们将试图通过一个主要的观测计划，利用近衍射限制红外成像和凯克激光制导星星自适应光学系统的光谱学，发现这些物体的更多例子，并将扩大亚恒星双星动态质量测量的样本。 虽然在研究褐矮星的整体性质方面已经取得了很大的进展，但对低质量超冷天体的理论预测在很大程度上还没有得到验证，尽管这种模型被广泛用于描述已知的亚恒星和系外行星种群的特征。这一提议的研究目标将与培训初级同事的更广泛影响同步实现。下一代天文学家将在快速发展的亚恒星天体物理学和自适应光学科学领域接受培训。特别是，发展激光引导星星自适应光学系统的观测技术和专门知识是迈向未来高角分辨率地基天文学的重要一步。

In this project, Dr. Liu and his research group will conduct a deep, sensitive search of the coldest known brown dwarfs to identify new substellar binaries suitable for dynamical mass determinations and to search for free-floating objects colder than anything currently known. They will attempt to uncover more examples of these objects through a major observational program employing near-diffraction limited infrared imaging and spectroscopy from the Keck laser guide star adaptive optics system, and will expand the sample of dynamical mass measurements for substellar binaries. While there has been great progress in studying the bulk properties of brown dwarfs, theoretical predictions of low-mass, ultracool objects are largely untested even though such models are widely used to characterize the known substellar and exoplanetary population.The research goals of this proposal will be accomplished in tandem with the broader impact of training junior colleagues. This next generation of astronomers will receive training in the rapidly growing fields of substellar astrophysics and science with adaptive optics. In particular, development of observational techniques and expertise with laser guide star adaptive optics systems is an important step toward future high angular resolution ground-based astronomy.