[论文解读] Spectral Dataset of Stripped-Envelope Supernovae from the Tsinghua Supernova Group

Danfeng Xiang, Xiaofeng Wang+41 more|arXiv (Cornell University)|Mar 13, 2026

Gamma-ray bursts and supernovae被引用 0

一句话总结

本论文提出一个包含 2010–2020 年 249 条光谱、来自 62 个去包层超新星（SESNe）的数据集，测量了伪等效宽度和蓝移速度，并分析光谱特征以揭示亚型趋势及前体星暴质量的含义。

ABSTRACT

The extent of envelope stripping in the progenitor stars is directly reflected in the diversity of spectral features observed in stripped-envelope supernovae (SESNe). Through extensive spectral observation and analysis, we aim to clarify the statistical differences between the subclasses of SESNe. The Tsinghua Supernova group obtained 249 optical spectra of 62 SESNe during the years from 2010 to 2020, covering phases from $-$16 to over 190 days relative to maximum light. Most spectra were obtained during the photospheric phases after the supernova explosion. For each spectrum, the pseudo-equivalent widths (pEWs) and blueshift velocities of principal lines were measured. We further investigated the common spectral features by analysing their velocity and strength correlations across all subtypes. We identify the feature near 6200~Å in SNe Ib as H$\mathrmα$ through comparison with SNe IIb and Ic, which resolves inconsistent literature interpretations. Our finding reveals prevalent residual hydrogen in SNe Ib, further supporting a continuous stripping sequence from SNe IIb to Ib. We observe a trend in increasing velocity among different subtypes of stripped-envelope SNe, with SNe IIb exhibiting the lowest line velocities, followed by Ib, Ic, and Ic-BL. Typically, the O~I lines in SNe Ic/Ic-BL are stronger than those seen in SNe IIb/Ib. In nebular phases, the [Ca II] emission dominates over [O I] in SNe IIb/Ib while [O I] is stronger in SNe Ic, including the He-rich SN 2016coi. This spectral dichotomy implies that progenitors of SNe Ic (BL) have more massive CO cores and hence higher initial masses.

研究动机与目标

• 通过汇编和分析大规模光谱数据集，阐明 SESNe 子类之间的统计差异。
• 在从超前最大值到晚 nebular 阶段的相位中量化光谱特征属性（pEW 和速度）。
• 研究氢保留和元素线行为，以推断包层剥离序列和前体质量。

提出的方法

• 收集并简化 2010–2020 年观测的 62 个 SESNe 的 249 条光谱。
• 为主要光谱线测量伪等效宽度和蓝移速度。
• 分析光谱线速度与强度在 SESNe 子类之间的相关性。
• 识别光谱特征（例如接近 6200 Å 的特征）并通过与 SN IIb 和 Ic 的对比确定物理身份。
• 比较 nebular 阶段 [Ca II] 与 [O I] 的强度在不同子类中的差异，以推断核心质量。

实验结果

研究问题

• RQ1 SESNe 子类（IIb、Ib、Ic、Ic-BL）之间在光谱特征上有哪些统计差异？
• RQ2 线速度和 pEW 如何随相位及子类相关？
• RQ3 SNe Ib 的 6200 Å 特征是否最佳解释为 Hα，这对 SNe Ib 中残留氢有何意义？
• RQ4 nebular 阶段 [Ca II] 与 [O I] 的强度对 CO 核心质量与前体初始质量有何指示？

主要发现

• 在 SNe Ib 中，6200 Å 的特征通过与 SNe IIb 和 Ic 的对比被确认为 Hα，表明 SNe Ib 中存在残留氢。
• 存在随子类变化的普遍速度趋势：IIb 最慢，其次 Ib、Ic，Ic-BL 速度增加。
• O I 线在 SNe Ic / Ic-BL 中通常比 IIb / Ib 更强。
• 在 nebular 阶段，IIb / Ib 中 [Ca II] 优势于 [O I]，而 [O I] 在 Ic 及富 He 的 SN 2016coi 中更强。
• 结果支持从 IIb 到 Ib 再到 Ic 的连续包层剥离序列，Ic / Ic-BL 的前体具有更大质量的 CO 核。