Chemical Abundances of Relic Red Giant Stars for Galactic Archeology

像我们银河系这样的星系是如何形成的？周期表中所有比氦重的化学元素的起源是什么？我和我的学生将进行银河考古学的研究，以追求这两个重要的基本起源问题。我们将创建非常古老的红巨星的外部可见层（大气层）的计算机模型，这些红巨星是我们银河系形成时代的遗迹。这将使我们能够对这些恒星发出的光谱进行计算建模，包括光谱的紫外线（UV），可见光和红外线（IR）波段。我们的模型处理的方式，气体粒子吸收光，并引起星星的发射光谱比竞争对手的模型更现实，它已被证明，这使我们能够模拟红巨星的光谱显着更高的精度。将我们的模拟光谱与国际地面和空间观测站（加拿大是其中许多观测站的合作伙伴）观测到的光谱进行比较，将使我们能够确定古老红巨星的化学成分和其他性质，而这一信息对于确定银河系如何形成和演变至关重要。我们的建议是及时的，因为许多正在进行或即将开始的大规模观测调查的前所未有的范围将获得光谱的数十万颗恒星在未来几年内，和潜在的数据只能实现，如果他们解释与现实的计算模型。在加拿大，我们有独特的能力提供最先进的建模，以解释作为下一代加拿大-法国-夏威夷望远镜可行性研究的一部分而提出的调查的恒星部分的数据。我们将应用一种相关的方法来研究更遥远的恒星群发出的集体光，例如围绕银河系运行的矮星系，以及在仙女座星系等附近其他较大星系中发现的大型星星团，以确定这些物体的性质和组成。我的研究学生将获得与同源领域相关的关键经验，如地球大气和太阳物理学，以及在现代数据中心环境中高性能技术计算的方法和技能培训。

How did galaxies such as our own Milky Way Galaxy form? What is the origin of all the chemical elements in the periodic table heavier than Helium? My students and I will carry out research in Galactic archeology to pursue these two important problems in fundamental origins. We will create computer models of the outer visible layers (the atmospheres) of very old red giant stars that are relics from the era in which our Milky Way Galaxy formed. This will allow us to computationally model the spectrum of the light emitted by these stars, including the ultraviolet (UV), visible, and the infrared (IR) bands of the spectrum. Our modelling treats the way that gas particles absorb light and give rise to star’s emitted spectrum more realistically than does rival modelling, and it has been shown that this allows us to simulate red giant stars’ spectra with significantly greater accuracy. Comparison of our simulated spectra to the observed spectra from international ground- and space-based observatories, in many of which Canada is a partner, will allow us to determine the chemical composition and other properties of old red giant stars, and this information is crucial to determining how the Galaxy formed and evolved. Our proposal is timely, because many on-going or soon-to-begin large scale observational surveys of unprecedented scope will obtain spectra of hundreds of thousands of stars over the next few years, and the potential of the data can only be realized if they are interpreted with realistic computational modelling. Within Canada, we are uniquely capable of providing state-of-the-art modelling to interpret data for the stellar component of the surveys being proposed as part of the feasibility study for the Next Generation Canada-France-Hawaii (ngCFHT) telescope. We will apply a related method to the collective light emitted by more remote groups of stars, such as the dwarf galaxies that orbit the Milky Way, and large star clusters that are found within other nearby larger galaxies such the Andromeda galaxy, to determine the properties and composition of those objects, too. My research students will acquire critical experience related to cognate areas such as terrestrial atmospheric and solar physics, and training in methods and skills of high performance technical computing in a modern data centre environment.