The Oxygen Crisis

奖项编号：AST-0607295 PI：托马斯艾尔斯机构：位于博尔德的科罗拉多大学标题：氧气危机摘要这里将要进行的研究集中在太阳物理学和其他领域的一个重大争议上-即太阳氧丰度的值。在过去的几年中，先进的三维时间相关的辐射流体动力学模拟的太阳大气和随后形成的禁止的O I和OH吸收功能已经指出，在建议的太阳氧丰度减少了近一个因素。这一修正使太阳值接近于目前星际介质和附近B星的预期值。然而，由于氧气作为一个重要的内部不透明度源的作用，这些值与太阳内部模型及其与日震学的良好一致性存在严重冲突。此外，最近对热红外线中一氧化碳振转带的研究提出了有关光球中层三维对流模型有效性的问题，并支持氧丰度与以前的高值更一致。这里将发展光球对流模拟的进一步独立观测试验，主要是在热红外线中，其中重要的连续谱和线不透明度源具有不同的，更简单的，而是对可见光的补充。第二个目标是继续探索光球的外边界，即所谓的磁过渡区，在那里，深层大气中的等离子体控制让位于高层的磁优势。在这个神秘的区域中，4.66微米的CO谱带表明了超冷（T ~ 3500 K）气体的惊人存在，这些气体突出到了应该是温暖的、分子敌对的色球层中。理解这个谜团对于全面描述外层大气中的热平衡和能量传输是至关重要的。太阳红外光谱成像技术的新进展将使十年来在原型上进行的观测研究成为可能。此外，目前的热廓线模拟将扩展到新的示踪剂，如OH和Ca II，将利用红外成像光谱学与NASA太阳紫外探测火箭飞行相协调的独特机会。该项目将提高我们对太阳大气结构的认识，能源运输，这与空间天气有关。除此之外，太阳的组成是天文学许多其他领域的关键基线。此外，高海拔的大气层”为研究与分子冷却灾难有关的过程提供了一个实验室。“这里的工作将提供研究生培训和相关的仪器开发，为更广泛的国家太阳观测站用户社区服务。除了通过专业出版物和会议记录进行传播外，与NSF使命相关的各种外展项目和社区服务活动将与这项工作联系起来。

AWARD NO: AST-0607295PI: Thomas AyresINSTITUTION: University of Colorado at BoulderTITLE: The Oxygen CrisisABSTRACTThe research to be undertaken here is focused on a significant controversy in solarphysics and beyond - namely the value of the solar oxygen abundance. In the past fewyears, advanced 3D time-dependent radiation-hydrodynamics simulations of the solaratmosphere and subsequent formation of forbidden O I and OH absorption features havepointed to a reduction in the recommended solar oxygen abundance of nearly a factor oftwo. This revision brings the solar value near that expected from the present-dayinterstellar medium and nearby B stars. However, because of the role of oxygen as asignificant interior opacity source, such values are in severe conflict with models of thesolar interior and their excellent agreement with helioseismology. Moreover, recentstudies of carbon monoxide rovibrational bands in the thermal infrared have raisedquestions concerning the validity of the 3-D convection models in the mid-photosphereand support an oxygen abundance more consistent with previous high values.Here further independent observational tests of the photospheric convection simulationswill be developed, primarily in the thermal infrared where the important continuum andline opacity sources have a different, simpler, but complementary character to those inthe visible. A secondary objective is to continue exploration of the outer boundary of thephotosphere, the so-called Magnetic Transition Zone, where plasma control in the deepatmosphere gives way to magnetic dominance in the higher layers. In this enigmaticregion, the 4.66 micron CO bands indicate the surprising presence of ultra-cool (T ~ 3500K) gas protruding into what should be the warm, molecule-hostile chromosphere.Understanding this puzzle is essential to the full description of heat balance and energytransport in the outer atmosphere. New advances in solar IR spectral imaging technologywill enable the observational studies that have been carried out in prototype for a decade.In addition, current thermal profile modeling will be extended to new tracers such as OHand Ca II, and a unique opportunity to coordinate IR imaging spectroscopy with a NASAsolar UV sounding rocket flight will be exploited.This project will advance our knowledge of the Sun's atmospheric structure and energytransport, which is relevant to space weather. Beyond this, the composition of the Sun is acrucial baseline for many other areas of astronomy. Furthermore, the high-altitudeCOmosphere" provides a laboratory for the study of processes associated withmolecular cooling catastrophes."The work here will provide graduate training and the associated instrument developmentwill serve the broader National Solar Observatory user community. In addition todissemination through professional publications and conference proceedings, a variety ofoutreach projects and community service activities relevant to the NSF mission will becarried out in connection with this work.