Observational Tests of Mixing in Low Mass Stars

小行星9624680 将开展恒星光谱学和光度学研究方案。 研究工作的具体目标是提供观测限制的化学丰度修改机制，认为是在不断发展的低质量恒星。 观测对象将包括银河系球状星团恒星。 已知这些恒星的光元素丰度各不相同。 在旧的疏散星团中演化的恒星也将被观察到。 这些类型的恒星是最明亮的恒星之一，最常被观测以获得用于化学丰度测定的数据。 在得出关于我们银河系化学史的结论之前，需要了解改变重要元素（如氧和锂）分布的过程。 将与其他机构的研究人员合作，实施一系列观测方案，这些方案将使用天文仪器中的一些最新技术。 这些方案包括： 1)研究星团恒星的同位素碳和其他轻元素丰度，作为恒星深层混合的探测器，并获得混合机制对恒星质量和成分的敏感性。 2)中等贫金属球状星团恒星混合开始位置的确定。 3)测量和分析明亮的球状星团恒星中紫外波长的氢化氮（NH）带强度，以直接确定氮的丰度（评估深度混合作用所需的关键投入）。 4)通过色星等图的宽度对球状星团中原始氧变化的限制。 与其他机构的科学家合作开发项目以获取数据，并对数据进行本地还原和分析，不仅有利于常驻教师（通过刺激专业发展），而且有利于本科生通过早期接触基础研究。 作为研究项目的补充，正在为物理/天文学系编制一门基础天体物理学（恒星大气和内部）课程。 将利用目前的恒星模型大气层制作一系列复杂天体物理过程的动画，作为课程的补充。 制作的动画将以Mpeg格式制作，并通过互联网提供给其他教师。 ***

9624680 Briley A program of research in stellar spectroscopy and photometry will be carried out. The research efforts are specifically targeted at providing observational constraints on the chemical abundance modifying mechanisms believed to be operating in evolving low mass stars. The objects to be observed will include galactic globular cluster stars. These stars are known to vary in their light-element abundances. Stars which are in evolving members of old open clusters of stars will also be observed. These types of stars are the among the brightest stars and are most often observed to obtain data for use in chemical abundance determinations. An understanding of the processes which alter the distribution of important elements, such as oxygen and lithium, from their primordial values is required before conclusions can be drawn regarding the chemical history of our galaxy. In collaboration with researchers at other institutions, a series of observational programs will be pursued which will use some of the most recent techniques in astronomical instrumentation. The programs include: 1) A study of isotopic carbon and other light element abundances in cluster stars as probes of deep mixing in the stars and to obtain the sensitivity of the mixing mechanism to stellar mass and composition. 2) The determination of the location of the onset of mixing in moderately metal-poor globular cluster stars. 3) Measurement and analysis of ultaviolet wavelength Nitrogen Hydride (NH) band strengths among bright globular cluster stars to directly determine nitrogen abundances (a crucial input required to assess the role of deep mixing). 4) Placing constraints on the limits of primordial oxygen variations in the globular clusters through the widths of their color-magnitude diagrams. The development of collaborative programs with scientists at other institutions to obtain data, with local reduction and analysis of the data, benefits not only the resident faculty (by stimulating profess ional growth), but also benefits the undergraduate students through early exposure to fundamental research. As a complement to the research projects, a course in basic astrophysics (stellar atmospheres and interiors) is being developed for the Physics/Astronomy Department. A series of animations of complex astrophysical processes will be developed, using current stellar model atmospheres, as a supplement to the course. The resulting animations will be developed in the Mpeg format and made available to other teachers over the Internet. ***