Physical Properties of the Coolest Brown Dwarfs

棕矮星是理解最小恒星和最大太阳系外行星之间差异的关键实验室。这个项目将通过一个主要的观测项目来扩大我们对已知最冷的棕矮星的理解，以确定它们的物理性质，其质量大约是木星的5倍。本科生和研究生将培养地面天文学两个关键领域的专业知识，即广域天文测量和激光制导恒星自适应光学。同时，PI将正式确定并加强一项专业发展倡议，向研究生传授长期成功所需的软技能。这一努力旨在提高学生作为初出茅庐的研究人员的能力，帮助他们在复杂的学术界中驾驭，并增加对职业发展的保留。这个观测项目将使用高精度的红外天文测量来测量距离，从而测量绝对星等和亮度，以获得定义明确的最冷棕矮星样本。高角分辨率的自适应光学成像将确定这些物体的多重性，并产生最酷的已知双星。对双星的后续表征将导致可分辨的分光光度和动力学质量，使迄今为止对恒星下进化模型和超冷大气的最强测试成为可能。

Brown dwarfs are key laboratories for understanding the differences between the smallest stars and the largest extrasolar planets. This program will expand our understanding of the coldest known brown dwarfs through a major observational program to determine their physical properties down to about 5 times the mass of Jupiter. Undergraduate and graduate students will develop expertise in two key areas of ground-based astronomy, namely wide-field astrometry and laser guide star adaptive optics. In parallel, the PI will formalize and enhance a professional development initiative to teach graduate students the soft skills needed for long-term success. This effort is geared towards enhancing students as budding researchers, helping them navigate the complexities of academia, and increasing retention along the career pipeline.This observational program will use high-precision infrared astrometry to measure distances, and thus absolute magnitudes and luminosities, for a well-defined sample of the coolest brown dwarfs. High angular resolution adaptive optics imaging will establish the multiplicity properties of these objects and yield the coolest known binaries. Follow-up characterization of the binaries will result in resolved spectrophotometry and dynamical masses, enabling the strongest tests to date of substellar evolutionary models and ultracool atmospheres.