CAREER: Understanding Stellar Overflows

职业：了解恒星溢出

• 批准号: 9702484
• 负责人: Adam Frank
• 金额: $ 36.9万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-01 至 2003-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9702484&HistoricalAwards=false
• 关键词: CAREER; Understanding; Stellar; Overflows

AST-9702484 Abstract - A Frank Bipolar outflows and highly collimated jets are nearly ubiquitous features associated with stellar mass loss. From Young Stellar Objects (YSOs) to Luminous Blue Variables (LBVs) and Planetary Nebulae (PNe) - the stellar cradle to the grave - there exists clear evidence for collimated gaseous flows in the form of narrow high velocity streams or extended bipolar lobes. In YSOs, LBVs and PNe collimated highly supersonic outflows are observed to be transporting prodigious amounts of energy and momentum from a central star . Outflows and jets must play a significant dynamical role in the evolution of the parent stars. The similarity of jets and bipolar outflows across the Hertzsprung- Russell (H-R) diagram must tell us something fundamental and quite general about the nature of stellar evolution, as well as the interaction of stars with their environments. A large database of high resolution observations , including observations from the Hubble Space Telescope (HST)) are available. A general, well tested suite of theory for explaining outflow collimation and propagation could serve as a powerful diagnostic tool linking the outflows to their often obscured sources. This could initiate substantial progress in two of the most fundamental issues facing modern astronomy: the need to understand stellar birth and stellar death. The research goals of this project are ambitious but attainable. First, to develop and refine such a general theory of collimated stellar outflows by detailing the basic physics which drives the collimation process. Second, to extend our understanding of the collimation and propagation of the outflows to include more realistic physics such as the effect of microphysical processes and magnetic fields. The research focuses on two major investigations. One goal of this study is to use PNe and PPNe morphologies to determine the route which stars like the sun follow as they evolve from the Giant to the Dwarf stage. The second project is a long range study of radiation-gasdynamic and magneto-gasdynamic collimation of jets from Young Stellar Objects. The final products of the research will be a suite of well tested tools which can bridge the gap between the theory and reality, allowing the histories of individual objects and classes of objects to be recovered. The educational and outreach goals of the project are equally ambitious: to use the accessibility inherent to numerical simulations (i.e. graphics and animations) along with the visual power of real and "synthetic" bipolar outflow observations as the core of a series of innovative programs in curriculum development, interactive planetarium displays and middle school outreach efforts. The efforts as a "popular" science writer and as a regular contributer to both DISCOVER and ASTRONOMY magazines have provided experiences in effective strategies for bringing science to wider audiences. These skills, and the fruits of the research, will be integrated into education initiatives which will introduce Planetarium visitors, college and middle school students to stellar astronomy as well as to wider issues in the workings of science as a whole.

双极喷流和高度准直射流几乎是与恒星质量损失相关的普遍特征。从年轻的恒星天体（YSOs）到发光蓝色变量（LBVs）和行星状星云（PNe）——恒星的摇篮到坟墓——存在明确的证据表明，以狭窄的高速流或扩展的双极叶的形式准直的气体流动。在yso中，lbv和PNe准直的超声速外流被观察到从中心恒星传输了大量的能量和动量。喷流和喷流在母星演化过程中起着重要的动力学作用。赫茨普龙-罗素（H-R）图上的喷流和双极流出的相似性，一定告诉了我们一些关于恒星演化本质的基本和相当普遍的东西，以及恒星与其环境的相互作用。一个大的高分辨率观测数据库，包括哈勃太空望远镜（HST）的观测。一套通用的、经过良好测试的理论来解释外流准直和传播，可以作为一种强大的诊断工具，将外流与其经常被遮挡的来源联系起来。这可能会在现代天文学面临的两个最基本问题上取得实质性进展：了解恒星诞生和恒星死亡的必要性。这个项目的研究目标雄心勃勃，但却是可以实现的。首先，通过详细阐述驱动准直过程的基本物理原理，发展和完善准直恒星外流的一般理论。其次，扩展我们对外流的准直和传播的理解，以包括更现实的物理，如微物理过程和磁场的影响。本研究集中于两项主要调查。这项研究的一个目标是利用PNe和PPNe的形态来确定像太阳这样的恒星从巨星阶段进化到矮星阶段所遵循的路线。第二个项目是对来自年轻恒星物体的喷流的辐射-气体动力学和磁-气体动力学准直的长期研究。研究的最终产品将是一套经过良好测试的工具，它可以弥合理论与现实之间的差距，允许恢复单个对象和对象类别的历史。该项目的教育和推广目标同样雄心勃勃：利用数值模拟固有的可访问性（即图形和动画）以及真实和“合成”双极流出观测的视觉力量，作为课程开发、互动天文馆展示和中学推广工作的一系列创新项目的核心。作为一名“受欢迎的”科学作家以及作为《发现》和《天文学》杂志的定期撰稿人，他的努力提供了将科学带给更广泛受众的有效策略方面的经验。这些技能和研究成果将被整合到教育计划中，向天文馆的游客、大学生和中学生介绍恒星天文学，以及更广泛的科学运作问题。