Ia 型超新星是恒星演化晚期的热核爆炸，它在宇宙学、星系演化和恒星物理等研究领域中都占有重要地位。Ia 型超新星的光度极高，且光变曲线具有高度一致性。科学家利用 Ia 型超新星的这些性质，成功地将其用作宇宙学大尺度的标准烛光来进行测距，发现宇宙在加速膨胀，从而揭示宇宙中存在暗能量。然而 Ia
型超新星的前身星仍不清楚，这将影响其测距的精度。论文首先阐述超新星的分类，然后介绍了 Ia 型超新星的研究历史和研究意义，还介绍了 Ia 型超新星观测和理论研究的现状。我们构建了碳氧白矮星+氦星系统演化通道，给出了 HD 265435 可能的演化历史，并预言了其未来的演化。 近来研究发现碳氧白矮星+氦星系统能够通过双简并星模型产生 Ia 型超新星。在这一通道中，当氦星演化到亚巨星阶段时，氦亚巨星将转移物质给碳氧白矮星，最终形成另一颗碳氧白矮星。两颗碳氧白矮星相互绕转，由于引力波辐射损失角动量，它们相互靠近并合。如果双白矮星总质量大于钱德拉塞卡质量极限将发生 Ia 型超新星爆炸。近年来，美国系外行星巡天望远镜发现了一个碳氧白矮星+氦星系统，即 HD 265435。该双星系统的轨道周期为 0.0688 天，碳氧白矮星和氦星的质量分别为 1.01±0.15𝑀⊙ 和 0.63^{+0.13}_{−0.12}𝑀⊙。在本论文中，我们通过构建碳氧白矮星 + 氦星系统演化通道，发现 HD 265435 可能来自于一个含有 5.18𝑀⊙ 主星和 3.66𝑀⊙ 次星的原初双星系统，初始轨道周期为 5200 天。该双星系统经历两次公共包层抛射后，将演化为碳氧白矮星+氦星系统。当氦星演化为一颗氦亚巨星时发生稳定的物质转移过程，系统将演化为一个总质量约为 1.58𝑀⊙ 的双白矮星系统。我们估计，HD 265435 大约在 7600 万年后通过双白矮星并合形成 Ia 型超新星爆炸。另外，HD 265435 还是未来空间引力波探测器（如 LISA、太极、天琴等）的潜在目标源。
其他摘要
As thermonuclear explosions late in stellar evolution, type Ia supernovae (SNe Ia)
play an important role in the study of cosmology, galaxy evolution and stellar physics.
Based on high luminosity and the significant uniformity of light curves, SNe Ia are
regarded as standard cosmological distance indicators leading to the important discovery that the Universe is expanding at an accelerating rate driven by dark energy.
However, the uncertainty of SN Ia progenitors may have great influence
on the accuracy of the detected cosmological distances. In this thesis, we briefly introduced classification of SNe, history and meaning of
researching SNe Ia. We also introduced observation and theoretical research status of
SNe Ia. We built the evolution channels of CO WD+He star systems, investigated the
evolution history of HD 265435 and predicted its future. It is known that the carbon-oxygen white dwarf (CO WD) + helium (He) star
system could produce SNe Ia by double-degenerate model. When evolves to giant
branch, the He star in the system would transfer material to primary star and become
another CO WD. Because of gravitational wave radiation, two WDs get close and merge
to produce a SN Ia if the total mass is larger than Chandarsekhar mass. Recently,
Trademark Electronic Search System (TESS) has discovered a CO WD+He star system (i.e. HD 265435) with a 0.0688 days orbital period. The masses of CO WD and
He star are 1.01 ± 0.15M⊙ and 0.63^{+0.13}_{−0.12}M⊙, respectively. In this thesis, we built the
evolution channels of CO WD+He star systems and researched the evolution history
of HD 265435. We found that it may originate from a primordial binary that has a
5.18M⊙ primary and a 3.66M⊙ secondary with an initial orbital period of 5200 days.
A CO WD+He star system would be formed after the primordial binary experiences
two common-envelope ejection processes. HD 265435 would evolve to a double WD
system with a 1.58M⊙ total mass after a stable mass-transfer process when the secondary becomes a helium subgiant. We estimated that it would take about 76 Myr for
HD 265435 to form an SN Ia. In addition, HD 265435 would be a potential target of
space-based gravitational wave observatories (e.g., LISA, Taiji and TianQin).
修改评论