EAPSI: Detailed Three-Dimension Simulations of an Unexplored Progenitor System for Type Ia Supernovae

Ia型超新星是白矮星的热核爆炸。它们是伟大的宇宙探测器，因为它们的亮度几乎总是相同的，并且可以根据经验进行标准化。这些物体在1999年被用来发现暗能量，这一成就在2011年获得诺贝尔奖。然而，爆炸的恒星的性质--前身系统--仍然是一个谜。这颗白矮星的质量是通过它的伴星吸积物质而增加的。虽然Ia型超新星已经被研究了30多年，但这些爆炸的前驱系统仍然存在争议。这个项目试图研究一个拟议的祖先系统，该系统在很大程度上仍未被探索。与京都大学动力学爆炸模型专家前田敬一合作，这位研究人员将创建一个Ia型超新星的计算机模拟，该超新星是由两颗不同质量的白矮星合并而成的。这一模拟将探索这样一种情况，即质量较小的白矮星被潮汐破坏，并附着在质量较大的白矮星上。这一模型有望解决以前的模型和观测之间的一些差异。更好地理解前身系统将提高它作为宇宙本质探测器的有效性。这个项目将创建一个Ia型超新星的流体动力学模拟，它来自一次被潮汐破坏的双衰变合并。这个模拟将被用来测试这种类型的爆炸的几个特性。它将探索由于旋转而可能产生的爆炸质量的范围。这将使该模型既可以适用于钱德拉塞卡质量，也可以适用于超级钱德拉爆炸。这种爆炸类型不应该作为超软X射线源容易观察到，并且应该是近乎球形的爆炸。这两点都将使其与目前的观测限制相兼容。该模型可以检验从这种类型的爆炸中预测的丰度，并检验低爆炸速度下碳的存在。该奖项由东亚和太平洋暑期学院项目资助一名美国研究生的暑期研究，由NSF和日本科学促进会共同资助。

Type Ia supernovae are thermonuclear explosions of white dwarf stars. They are great cosmic probes because their brightness is almost always the same and can be standardized empirically. These objects were used to discover the Dark Energy in 1999, an accomplishment recognized with the Nobel Prize in 2011. However, the nature of the stars that blow up?the progenitor system?remains a bit of a mystery. The mass of the white dwarf is increased by accreting material from its companion star. While Type Ia supernovae have been studied for over 30 years the progenitor system for these explosions is still disputed. This project seeks to study one proposed progenitor system that has remained largely unexplored. In collaboration with Keiichi Maeda, an expert in dynamical explosion models, at Kyoto University the researcher will create a computer simulation of a Type Ia supernova from the merger of two white dwarfs of differing masses. This simulation will explore the case where the less massive white dwarf is tidally disrupted and accretes onto the more massive white dwarf. This model is expected to resolve some discrepancies between previous models and observations. A better understanding of the progenitor system will improve its usefulness to as probes of the nature of Universe.This project will create a hydrodynamic simulation of a Type Ia supernova from a tidally disrupted double degnerate merger. This simulation will be used to test several properties of this type of explosion. It will explore the range of possible explosion masses due to spin up. This would allow this model to fit both Chandrasekhar mass as well as superchandra explosions. This explosion type should not be easily observable as a supersoft X-ray source, and should be a nearly spherical explosion. Both of these will make it compatible with current observational constraints. This model can test the abundances predicted from this type of explosion and test for the presence of carbon at low explosion velocities. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Japan Society for the Promotion of Science.