The Solar Oxygen Problem: Crisis, Catastrophe, or Opportunity?

科罗拉多大学的艾尔斯博士将对太阳外层进行多方面的研究。 一场争论动摇了太阳物理学，争论的焦点是通常被视为最《双城之战》的细节：氧丰度。在过去的几年里，光球中测得的丰度下降了近两倍，这主要是由于将复杂的3D对流模型应用于关键原子示踪剂（例如原子氧和OH和CO等含氧分子）。据说新的低值解决了热恒星和星际介质丰度中的几个悬而未决的问题，但代价是破坏了之前太阳内部理论模型（其中氧气是一个关键的不透明源）与日震学高度精确的内部声速剖面之间非常好的一致性。当人们考虑到天体物理学的不同领域的后果时，太阳低O问题将面临危机，这些领域基本上依赖于太阳提供基线化学成分;如果太阳丰度和日震学的研究不能协调一致，甚至会发生灾难。目前的工作将通过多管齐下的战略解决这些不足之处。一个关键目标是利用基特峰天文台最近升级的傅里叶变换光谱仪，以尽可能高的光谱分辨率和信噪比制作一系列新的太阳图集。第二个目标将是仔细测试最新一代的三维对流模型，并作出必要的经验修改，以适用于分子形成问题的上层。第三个相关的目标是继续探索光球的外边界，在那里，深层大气的高度有序的纤维场变得严重扭曲和缠结，导致局部加热，将气体喷流推进日冕，并通常造成破坏。这项研究将增进对太阳的了解，特别是从深光球层到磁复杂的低色球层的大气结构和能量传输;与空间天气有关，这是天文学中少数几个具有直接社会影响的领域之一。在太阳之外，更好地确定氧（和碳）丰度，以及稀有的C和O同位素，对依赖太阳基线的许多天文学领域至关重要。与国家太阳观测站合作进行的仪器开发将为更广泛的国家统计局用户群体服务;以及为定于下一个十年运行的先进技术太阳望远镜（ATST）寻找路径。ATST不仅有利于太阳观测者，也有利于专门的夜间项目，如明亮物体附近微弱红外源的日冕。最后，将开展与NSF相关的各种外展项目和社区服务活动。

Dr. Ayres of the University of Colorado will undertake a multifaceted study of the outer layers of the Sun. A controversy has shaken solar physics, over what ordinarily might be seen as the most arcane of details: the oxygen abundance. In the past few years, the measured abundance in the photosphere has plummeted nearly a factor of two, driven mainly by application of sophisticated 3D convection models to key atomic tracers such as atomic oxygen and oxygen-bearing molecules like OH and CO. The new low value is said to resolve several outstanding questions in the abundances in hot stars and the interstellar medium, but at the expense of wrecking the previous spectacularly good agreement between theoretical models of the solar interior (where oxygen is a crucial opacity source) and highly precise internal sound speed profiles from helioseismology. The solar low-O problem borders on a crisis, when one considers ramifications for diverse areas of astrophysics that rely fundamentally on the Sun to provide a baseline chemical composition; and even a catastrophe if the studies of solar abundances and helioseismology cannot be reconciled. The present work will address these deficiencies with a multi-pronged strategy. A key objective will be to develop a series of new solar atlases at the highest possible spectral resolution and signal-to-noise, exploiting the recently upgraded Fourier transform spectrometer at Kitt Peak Observatory. A second objective will be to carefully test the most recent generation of 3D convection models, and to make such empirical modifications to the upper layers as necessary to apply them to molecular formation problems. A third, related objective, is to continue exploring the outer boundary of the photosphere, where the highly ordered fibril fields of the deep atmosphere become severely twisted and tangled, causing local heating, propelling jets of gas into the corona, and generally wreaking havoc. This study will advance knowledge of our Sun, specifically atmospheric structure and energy transport from the deep photosphere out to the magnetically complex low chromosphere; relevant to space weather, one of few areas in astronomy that has direct societal impact. Beyond the Sun, better determinations of the oxygen (and carbon) abundance, and the rare isotopes of C and O, are crucial to many areas of astronomy that rely on the solar baseline. Ongoing instrumental developments, in partnership with the National Solar Observatory, will serve the broader NSO user community; as well as path finding for the Advanced Technology Solar Telescope (ATST), slated for operation in the next decade. ATST will benefit not only solar observers, but also specialized nighttime projects such as coronography of faint IR sources near bright objects. Finally, a variety of outreach projects and community service activities relevant to NSF will be carried out.