RUI: Proto-Planetary Nebulae - High-Resolution Studies with Enlarged Sample

该计划的目标是通过确定原行星星云的物理性质，更好地理解原行星星云，即从渐近巨型分支演化到行星状星云阶段的恒星。这些天体代表了恒星演化周期中一个重要但鲜为人知的阶段。该项目正在扩大已确认的原行星星云的样本，对它们进行高分辨率的光谱和空间观测，特别是利用分子氢发射来研究它们的性质。美国国家科学基金会对这些天体的脉动可变性进行了一项独特的、长达十年的研究，这项研究正在继续和扩大，目前正在分析和准备出版。该计划涉及以下内容：(1)分析与迄今所研究的大多数星云不同性质的原始行星星云候选的扩大样本；(2)高分辨率分子光谱，以研究环绕恒星包层的化学和动力学；(3)原始行星星云的高分辨率红外成像，以研究其热发射直接产生的尘埃；(4)对中心恒星的高分辨率化学丰度研究，以调查核合成对渐近巨星枝的影响；以及(5)分析和继续在瓦尔帕莱索大学进行的原始行星星云的独特光变研究。大量的观测数据已经掌握。将在国家天文台使用望远镜和仪器获取更多数据。广泛影响：这项活动对理科学生的培训、文科学生的教育以及瓦尔帕莱索大学的科学基础设施都有非常积极的影响。每年有三名学生担任该项目的研究助理。他们接受了使用现代天文设备的培训，学习如何进行观测和减少数据，并学习如何分析数据和准备结果以供传播。他们几乎经历了研究计划的所有阶段，并在会议上展示他们的结果。积极寻找妇女和少数群体作为参与者，项目主任在让女学生参与他的研究方面有很好的记录。本研究项目的激动人心之处在于融入了通识教育的天文课堂和一些实验室使用的真实数据的研究经验。瓦尔帕莱索大学是一所本科院校，该项目提供的天文学项目的持续活力增强了该大学的研究基础设施。该计划提供了更现代的CCD探测器和新的数据计算机

The goal of this program is to better understand proto-planetary nebulae, objects in transition as evolved stars from the asymptotic giant branch to the planetary nebula phase, by determining their physical properties. These objects represent an important but poorly understood phase in the evolutionary cycle of stars. The project is enlarging the sample of confirmed proto-planetary nebulae, to carry out high-resolution spectral and spatial observations of them, especially using molecular hydrogen emission, to investigate their properties. The results of a unique, decade-long NSF-supported study of pulsational variability in these objects, a study being continued and extended, are being analyzed and prepared for publication. The program here involves the following: (1) an analysis of an enlarged sample of proto-planetary nebulae candidates chosen with different properties from most of those studied thus far; (2) high-resolution spectroscopy of molecules to study the chemistry and dynamics of the circumstellar envelopes; (3) high-resolution infrared imaging of proto-planetary nebulae to study the dust directly from its thermal emission; (4) a high- resolution chemical abundance study of the central stars to investigate the effects of nucleosynthesis on the asymptotic giant branch; and (5) analysis and continuation of the unique light variability study of proto-planetary nebulae being carried out at Valparaiso University. A significant amount of the observational data is already in hand. Additional data will be acquired with telescopes and instruments at the national astronomical observatories.Broader Impacts: This activity has a very positive impact on the training of science students, the education of liberal arts students, and on the infrastructure for science at Valparaiso University. Three students each year serve as research assistants on the project. They are trained in the use of modern astronomical equipment, taught to carry out the observations and reduce the data, and learn how to analyze the data and prepare the results for dissemination. They experience almost all phases of a research program and present their results at conferences. Women and minorities are actively sought as participants, and the project director has a strong record of having women students participate in his research. The excitement of this research project is integrated into the general education astronomy classes and some of the real data used in laboratory research experience. The research infrastructure at Valparaiso University, an undergraduate institution, is enhanced by the continued vitality of the astronomy program that this project provides. The program provides a more modern CCD detector and new computers for data