The Realizability of the Double-Detonation Mechanism for Type Ia Supernovae

Ia型超新星（SN）在测量宇宙的加速膨胀方面发挥着重要作用，产生了宇宙中一半的重金属，并作为恒星流体力学，核物理，双星演化和天体物理学的许多其他方面的试验台。然而，尽管它们的重要性和几十年的观测和理论研究，引起这些爆炸的恒星系统的详细性质仍然不确定。 亚拉巴马塔斯卡卢萨大学的一个研究小组将使用基于计算机的数值模拟来研究超新星爆炸最有希望的候选场景之一。 这种情况被称为“双重爆炸”机制，首先是一颗高度致密的白色矮星星星表面的氦爆炸，这反过来又在该星星的核心产生碳燃烧爆炸。 这项研究将涉及对研究生和本科生进行高性能计算和科学软件开发方面的培训。 沿着研究成果，这项工作将制作面向普通观众的科学成果短视频、面向小团体的便携式天文馆程序，以及可由高年级天文学课程的学生运行的恒星爆炸的简单模拟。理解双爆炸机制仍然存在障碍，这项工作将有助于解决这些障碍。 在星星的氦壳层中第一次点火的详细机制仍然不清楚，这使得人们对爆炸开始的这个关键阶段的鲁棒性提出了质疑。为了使这一方案成为Ia超新星的主要贡献者，点火过程不仅必须在微调下可行，而且必须是鲁棒的和几乎通用的。其次，根据最近的模拟，很明显，爆炸星星外层的详细结构和伴星星星的存在对于确定所产生的超新星是否与观察到的超新星相匹配至关重要。使用定制的模拟，这项工作将确定是否一个现实的点火和表面层结构放置在一个双星星系统导致现实的超新星。 该项目由天文科学部和刺激竞争性研究的既定计划（EPSCoR）共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Type Ia supernovae (SN) play an essential role in measuring the accelerating expansion of the Universe, produce half of the Universe’s heavy metals, and serve as testbeds for stellar hydrodynamics, nuclear physics, binary stellar evolution, and many other aspects of astrophysics. However, despite their importance and several decades of observational and theoretical investigation, the detailed nature of the stellar systems that give rise to these explosions remains uncertain. A research team at the University of Alabama Tuscaloosa will use computer-based numerical simulations to investigate one of the most promising candidate scenarios for a SN Ia explosion. This scenario, called the “double-detonation” mechanism, starts with an explosive helium detonation on the surface of a highly compact white dwarf star, which in turn yields a carbon-burning detonation in the core of that star. The research will involve the training of graduate and undergraduate students in high performance computing and the development of scientific software. Along with research products, this work will produce short videos of scientific results intended for a general audience, a portable planetarium program for small groups, and simple simulations of stellar explosions that can be run by students in upper-division astronomy courses.Obstacles remain to understanding the double-detonation mechanism and this work will help resolve them. The detailed mechanism of the first ignition in the helium shell of the star is still unclear, calling into question the robustness of this critical stage of the beginning of the explosion. In order for this scenario to be viable as a major contributor to SNe Ia, the ignition process must not just be possible under fine-tuning, but robust and almost universal. Secondly, based on recent simulations, it is clear that the detailed structure of the outer layers of the exploding star and the presence of the companion star are critical to determining whether the resulting supernova matches those observed. Using tailored simulations, the work will determine whether a realistic ignition and surface layer structure placed in a binary star system leads to realistic supernovae. This project is jointly funded by the Division of Astronomical Sciences and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.