Three-dimensional stellar physics simulations of exotic element formation

奇异元素形成的三维恒星物理模拟

• 批准号: RGPIN-2019-07164
• 负责人: Herwig, Falk
• 金额: $ 3.64万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=762997
• 关键词: Three; dimensional; stellar; physics; simulations

Advances in observational astronomy have enabled a greatly expanded picture of the different types of abundance patterns and chemical fingerprints that exist in the universe. In large surveys that target metal-poor stars that have formed in the early universe stars with rare and exotic abundance patterns are now frequently found. These abundance observations of stars have evolved into the important tool of galactic archeology to study the formation and evolution of galaxies, and the cosmological processes in the early universe. This project will enhance our understanding of how the elements form in the exotic stellar evolution toward black hole formation of supernova explosion. The first stars that formed shortly after the Big Bang must have possessed yet to be determined unusual modes of element formation as is evident from some of the most intriguing and anomalous abundance patterns found in the most metal-poor and oldest stars. Our approach is based on a new generation of three-dimensional simulations of the turbulent, hydrodynamic conditions of element formation. These simulations require the impressive computing power of Compute Canada's new Niagara supercomputer, that we have used earlier this year together with our international team to perform the largest simulations of turbulent core convection in a massive star. With these three-dimensional simulations we expect to be able to overcome the limitations of present-day one-dimensional spherically-symmetric stellar evolution simulations that include turbulent mixing only via a parameterized model. By including the often violent and energetic feedback from nuclear burning into realistic three-dimensional simulations at very high spatial resolution, using about one half of the entire Niagara computer's 60,000 compute cores at a given time during a simulation run, we will generate unique astrophysics simulation data sets of the turbulent conditions of convective shells in massive stars, such as the merger of a C- and O-burning shell. These simulations will provide a view of unprecedented detail on how the elements form in the final stages of a star's life before exploding as a supernova. An important goal of our research will be to improve our understanding of the exotic conditions in the first massive stars that formed after the Big Bang from the initial, pristine and metal-free material. One-dimensional models suggest that during interactions of convective H- and He-burning shells as much energy per unit time as an entire galaxy produces would be generated inside the star, although of course only for a short time. Our three-dimensional simulations will reveal how a real star would respond to such extreme and energetic events. They will show if and how the anomalous abundance patterns observed in the most metal-poor and oldest stars can originate in these first stars. In this way our research will help to solve the puzzle of element formation and evolution in the early universe.

观察天文学的进展使宇宙中存在的不同类型的丰度模式和化学指纹的图景大大扩展。在针对早期宇宙恒星中形成的具有罕见和异国情调丰度模式的靶向金属贫困星的大型调查中，经常发现。恒星的这些丰度观察已经演变成银河考古学的重要工具，以研究星系的形成和演变以及早期宇宙中的宇宙学过程。 该项目将增强我们对异国情调恒星进化中元素如何向超新星爆炸形成的元素形成的理解。大爆炸之后不久形成的第一批恒星一定尚未确定不寻常的元素形成模式，这是从最贫穷和最古老的恒星中发现的一些最有趣，最异常的丰度模式可以明显看出的。 我们的方法基于新一代的三维模拟，对元素形成的湍流，流体动力条件。这些模拟要求计算加拿大新的尼亚加拉超级计算机的令人印象深刻的计算能力，我们今年早些时候与国际团队一起使用了最大的巨大恒星中湍流核心对流模拟模拟。 在这些三维模拟的情况下，我们希望能够克服当今一维球形对称恒星进化模拟的局限性，这些恒星演化模拟包括仅通过参数化模型进行湍流混合。 By including the often violent and energetic feedback from nuclear burning into realistic three-dimensional simulations at very high spatial resolution, using about one half of the entire Niagara computer's 60,000 compute cores at a given time during a simulation run, we will generate unique astrophysics simulation data sets of the turbulent conditions of convective shells in massive stars, such as the merger of a C- and O-burning shell.这些模拟将提供前所未有的细节，以了解恒星生活的最后阶段中如何形成元素，然后以超新星爆炸。 我们研究的一个重要目标是提高我们对最初，原始和无金属材料大爆炸后首批大型恒星中对异国情调的理解。一维模型表明，在对流H-和HE燃烧的壳的相互作用中，每单位时间与整个银河系产生的能量一样多，但在恒星内会产生，尽管当然只有很短的时间。我们的三维模拟将揭示真正的恒星如何应对如此极端和充满活力的事件。他们将表明在最贫穷和最古老的恒星中观察到的异常丰度模式是否以及如何起源于这些第一颗恒星。这样，我们的研究将有助于解决早期宇宙中元素形成和进化的难题。