NORMAL TYPE Ia SUPERNOVAE FROM VIOLENT MERGERS OF WHITE DWARF BINARIES
NORMAL TYPE Ia SUPERNOVAE FROM VIOLENT MERGERS OF WHITE DWARF BINARIES
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DOI：
10.1088/2041-8205/747/1/l10
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发表时间：
2012-01
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影响因子：
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通讯作者：
R. Pakmor;M. Kromer;S. Taubenberger;S. Sim;F. Röpke;W. Hillebrandt
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作者：
R. Pakmor;M. Kromer;S. Taubenberger;S. Sim;F. Röpke;W. Hillebrandt
关于Ia型超新星（SNe Ia）的祖先系统，最重要的问题之一是两颗白色矮星的合并是否会导致重现正常事件观测的爆炸。在这里，我们提出了一个完整的三维模拟的暴力合并的两个碳氧白色矮星的质量为0.9 M的倒坍和1.1 M相结合的非常高的分辨率和精确的初始条件。一个经过测试的代码组合用于研究系统。我们从动力学的螺旋阶段开始，并遵循随后的热核爆炸的合理假设下，爆炸形式的合并过程。然后，我们进行详细的核合成计算和辐射传输模拟预测合成观测同源膨胀超新星喷出物。我们发现，我们的合并，产生约0.62 M的56 Ni的反射，合成的彩色光变曲线显示出良好的一致性，正常的SNe Ia在所有波段从U到K。在最大光附近的合成光谱中的线速度也与观测吻合得很好。我们的结论是，大质量白色矮星的剧烈合并可以非常类似于正常的Ia超新星。因此，根据这些大规模系统的数量，这些合并可能至少会对观测到的正常Ia超新星的数量做出一小部分贡献。
One of the most important questions regarding the progenitor systems of Type Ia supernovae (SNe Ia) is whether mergers of two white dwarfs can lead to explosions that reproduce observations of normal events. Here we present a fully three-dimensional simulation of a violent merger of two carbon–oxygen white dwarfs with masses of 0.9 M☉ and 1.1 M☉ combining very high resolution and exact initial conditions. A well-tested combination of codes is used to study the system. We start with the dynamical inspiral phase and follow the subsequent thermonuclear explosion under the plausible assumption that a detonation forms in the process of merging. We then perform detailed nucleosynthesis calculations and radiative transfer simulations to predict synthetic observables from the homologously expanding supernova ejecta. We find that synthetic color light curves of our merger, which produces about 0.62 M☉ of 56Ni, show good agreement with those observed for normal SNe Ia in all wave bands from U to K. Line velocities in synthetic spectra around maximum light also agree well with observations. We conclude that violent mergers of massive white dwarfs can closely resemble normal SNe Ia. Therefore, depending on the number of such massive systems available these mergers may contribute at least a small fraction to the observed population of normal SNe Ia.