Phoenix Giants: their connection to the fate of short-orbital period binary stars and their potential for rebirthing planetary systems

Carl Melis博士被授予NSF天文学和天体物理学博士后奖学金，在加州大学圣地亚哥分校（UCSD）开展研究和教育计划。多恒星系统在我们的银河系中无处不在，在其他星系中也可能存在。了解这些系统如何随着时间的推移而演变，特别是当单个组件开始恒星演化的巨大阶段时，对于确定这些恒星群的最终状态以及它们将如何影响其宿主星系的演化至关重要。Melis博士将描述PI论文研究中发现的一类新的首次上升巨星，并将它们与一类特殊的短轨道周期双星系统的多星演化的最后阶段联系起来。被称为“凤凰巨人”，这些第一次上升的巨星即将结束他们的生命，但被尘埃和气体盘包围，类似于年轻的行星形成恒星周围发现的。该研究计划将包括从近红外到微波的全面观测活动，这些数据集的模型拟合，以推导出凤凰巨盘的结构，以及描述当主要进入第一个上升的巨大演化阶段时紧密结合对之间相互作用的分析和数值模型的发展。凤凰巨星盘结构的观测结果的分析和数值模拟结果的比较将有助于连接凤凰巨星现象和短轨道周期双星的命运。获得的数据还将扩展到探索凤凰巨盘是否是形成原行星的宜居环境，从而开始回答这些恒星是否可以在数十亿年后经历第二个行星形成时期的问题。梅利斯博士还将开展一项教育和外展计划，旨在招募、保留和提高科学、技术、工程、数学（STEM）Melis博士将开发和教授UCSD高级本科物理和工程专业的实验室课程，该课程将结合最近教育研究的最佳实践和在其他机构成功实施的天文学实验室课程的经验教训。该实验室课程将侧重于通过发展相关技术技能为学生在STEM中进行高级学术研究或行业工作做好准备，但也将向学生介绍观测天文学研究的基础知识。梅利斯博士还将与ASTRO项目志愿者将天文学带到大学预科教育的最早阶段，在那里年轻的头脑可以转向科学。这两个教育项目将在年轻学生的头脑中播下科学事业的种子，并为他们提供在大学环境中成功走上STEM职业道路的工具。

Dr. Carl Melis is awarded an NSF Astronomy and Astrophysics Postdoctoral Fellowship to carry out a program of research and education at the University of California, San Diego (UCSD). Multiple stellar systems are ubiquitous in our Galaxy and likely in other galaxies as well. Understanding how these systems evolve over time, especially when individual components begin the giant phase of stellar evolution, are critical in determining the final states of these groups of stars and how they will affect the evolution of their host galaxies. Dr. Melis will characterize a new class of first-ascent giant stars discovered in the PI's thesis research and will connect them to the final stages of multiple-star evolution for a special class of short orbital-period binary systems. Dubbed "Phoenix Giants," these first-ascent giant stars are nearing the end of their lives, yet are surrounded by dusty and gaseous disks similar to those found around young, planet forming stars. The research program will include a comprehensive observational campaign extending from the near-infrared to the microwave, model fitting of these data sets to derive the structures of Phoenix Giant disks, and the development of analytical and numerical models describing the interaction between tightly bound pairs when the primary enters into the first-ascent giant phase of evolution. Comparison of the observational results for Phoenix Giant disk structure to the analytical and numerical modeling results will aid in connecting the Phoenix Giant phenomenon and the fate of short orbital-period binaries. The data obtained will also be extended to probe whether Phoenix Giant disks are hospitable environments for forming protoplanets and hence to begin to answer the question of whether these stars can undergo a second epoch of planet formation billions of years after their first.Dr. Melis will also conduct a program of education and outreach aimed at the recruitment, retention, and advancement of students in science, technology, engineering, and mathematics (STEM). Dr. Melis will develop and teach a laboratory course for UCSD advanced undergraduate physics and engineering majors that will incorporate best practices from recent educational research and lessons learned from astronomy laboratory courses successfully implemented at other institutions. This laboratory course will focus on preparing students for advanced academic studies or industry work within STEM through the development of relevant technical skills, but will also introduce students to the basics of observational astronomy research. Dr. Melis will also volunteer with Project ASTRO to bring astronomy to the earliest levels of pre collegiate education where young minds can be turned on to science. These two educational programs will plant the seeds of a science career in young students' minds and provide them the tools in a collegiate setting to succeed in a STEM career path.