Ia 型超新星在天文学研究中占有重要的地位。通过 Ia 型超新星测距，人们发现当前的宇宙处于加速膨胀中。然而，关于 Ia 型超新星是怎么来的(即其前身星问题)，还有许多问题需要解决。前身星问题得不到解决将影响 Ia 型超新星作为距离指示器的测距精确。目前关于 Ia 型超新星唯一的共识是它起源于双星系统中CO WD的热核爆炸。然而，它爆炸前所在双星系统的类型，以及如何触发CO WD中心的热核爆炸仍然在讨论中。在本论文中，我们首先介绍了关于 Ia 型超新星的研究历史、研究现状及研究意义，然后着重介绍了 Ia 型超新星的观测特征、爆炸模型及当前流行的前身星模型。双简并星模型是两种主流的 Ia 型超新星前身星模型之一，近来的研究发现双白矮星很可能只有在剧烈并合时发生 Ia 型超新星爆炸。双极星云 Henize 2-428 的中心是一个双白矮星系统，该双白矮星系统的总质量约为 1.76 M⊙，质量比约为 1，轨道周期约为 4.2 小时。该双白矮星系统是到目前为止唯一的一个 Ia 型超新星剧烈并合模型前身星候选体。在本论文中，我们构建了双极星云 Henize
2-428 中心双白矮星系统的演化历史。我们发现双极星云 Henize 2-428 很可能起源于原初主星质量约 5.4 M⊙、原初伴星质量约为 2.7 M⊙、初始轨道周期约为 15.9天的双星系统。该双白矮星系统的形成经历了两次洛希瓣物质外流、两次公共包层抛射。根据我们目前的研究，我们估计 8 亿 4 千万年后，该双白矮星系统将并合 (由引力波辐射提取双白矮星角动量驱使并合)，将通过剧烈并合产生 Ia 型超新星现象。我们还发现需要一个大的公共包层抛射系数才能产生类似于 Henize 2-428 的双星系统。我们估计在剧烈并合模型下 Ia 型超新星的诞生率最多为 2.9 × 10?4 yr?1，并且其延迟时标大于 9 千万年。
其他摘要
Type Ia supernovae (SNe Ia) play an important role in the astrophysics. According
to the observation of SN Ia, it has been verified that the universe is expanding at an
increasing rate. However, the origin of SN Ia (e.g. the progenitor system) still remain
uncertain, which can affect the accuracy of distance measurement. So far, the only
certain thing about SNe Ia is that they are originated from thermonuclear runaway of
carbon-oxygen white dwarfs, but the type of binary systems before explosions and the
mechanism of how to trigger the explosion are still under debate. In this thesis, we
introduced the history, present situation and meaning of research on SN Ia at first, and
then introduced the observational features, explosion models and popular progenitor
models of SN Ia.The double degenerate systems that contains double white dwarfs(DD WDs), is
most favoured progenitors in recent studiedies. The double CO WDs that meet violent
merger conditions (VM model) is probably producting SNe Ia. The nucleus of bipolar
planetary nebula Henize 2-428 is the first candiate that will produce SN Ia under the
prediction of VM model. The system cosists of two nearly eqaul mass white dwars
that has a total mass of 1.76 M⊙, with an orbital period of 4.2 hours. In this work, we
study the evolution history of Henize 2-428. We find that the bipolar planetary nebula
probablly originate from the primordial binary system that have a 5.4 M⊙ primodial
primay and a 2.7 M⊙ primodial seconday, with their intial period of 15.9 days. The DD
CO WDs of Henize 2-428 is formed after two times Roche lobe overflow and two times
common envelope (CE) ejection from primodial binaries. According to our research,
gravational wave raidiation drives the DD WDs to merge about 840 Myr, since they are
formed. The outcome of the merge of DD WDs, according to VM model, is SN Ia. In
addition, we figure out that a large CE ejection efficiency is necessay that can produce
double CO WDs which are similar to Henize 2-428. We also estimate the rate of SNe
Ia from the violent merger scenario is at most 2.9 × 10?4 yr?1 and the delay time is in
rage of ～ 90 Myr to Hubble time.
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