Past and future of the central double-degenerate core of Henize 2-428
Past and future of the central double-degenerate core of Henize 2-428
复制标题
Henize 2-428 中央双简并核心的过去和未来
DOI：
10.1088/1674-4527/19/4/57
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发表时间：
2019
影响因子：
1.8
通讯作者：
王博
中科院分区：
文献类型：
--
作者：
Wu D.;Liu D.;王博
有人认为Ia型超新星（SNe Ia）可能产生于双简并模型的剧烈合并情景，即当双碳氧白色矮星（CO WD）合并时可能产生热核爆炸。最近发现双极行星状星云Henize 2-428的核心由一个双CO WD系统组成，其总质量为1.76 M <$3，质量比为1.01，轨道周期为1.42 h，这是第一个也是唯一一个被发现的超新星Ia的前身候选者。在这项工作中，我们的目标是再现中央双CO WD的Henize 2-428的进化历史。我们发现行星状星云Henize 2-428可能起源于一个初始轨道周期为15.9 d的原始双星，它的主恒星为15.4 M，副恒星为12.7 M。双CO WD是在原始双星经历两次Roche瓣溢出和两次共包络喷出过程后形成的。根据我们的计算，双CO WD诞生后在引力波辐射驱动下合并形成SN Ia大约需要1840 Myr。为了产生Henize 2-428的当前状态，需要大的公共包络参数。我们还估计，在剧烈合并的情况下，超新星Ia的速率最多为2.9× 10− 4 yr− 1，延迟时间在1.9亿年到哈勃时间之间。
It has been suggested that Type Ia supernovae (SNe Ia) could be produced in the conditions of the violent merger scenario of the double-degenerate model, in which a thermonuclear explosion could be produced when a double carbon-oxygen white dwarf (CO WD) merges. It has been recently found that the nucleus of the bipolar planetary nebula Henize 2–428 consists of a double CO WD system that has a total mass of∼ 1.76 M⊙, a mass ratio of∼ 1 and an orbital period of∼ 4.2 h, which is the first and only discovered progenitor candidate for an SN Ia predicted by the violent merger scenario. In this work, we aim to reproduce the evolutionary history of the central double CO WD of Henize 2–428. We find that the planetary nebula Henize 2–428 may originate from a primordial binary that has a∼ 5.4 M⊙ primary and a∼ 2.7 M⊙ secondary with an initial orbital period of∼ 15.9 d. The double CO WD was formed after the primordial binary experienced two Roche-lobe overflows and two common-envelope ejection processes. According to our calculations, it takes about∼ 840Myr for the double CO WD to merge and form an SN Ia driven by gravitational wave radiation after their birth. To produce the current status of Henize 2–428, a large common-envelope parameter is needed. We also estimate that the rate of SNe Ia from the violent merger scenario is at most 2.9× 10− 4 yr− 1, and that the delay time is in the range of∼ 90 Myr to the Hubble time.