AI 中文总结
本研究基于 JWST 观测 2024vjm 暗弱 Iax 型超新星爆发后 200 天的光谱与测光，用 PHOENIX/1D 模型开展研究，揭示了其尘埃、元素组成等特性，为 Iax 型超新星前身系统参数提供了严格约束。
AI 中文摘要
我们报告了在爆发后 202.8 静止帧天获得的暗弱 Iax 型超新星（SN Iax）2024vjm 的 JWST 光谱和测光数据。该光谱呈现出丰富的禁线，来自低电离、中等质量和铁族元素，其中值得注意的是[Ni II] 6.64 微米共振线，它是稳定镍的直接指标。在温暖尘埃连续谱中探测到强 CO 和 SiO 发射；这些光谱特性与预先存在的而非新形成的尘埃一致。我们使用通用恒星大气代码 PHOENIX/1D 结合简化的抛射体模型计算合成光谱。这些模型能够合理地重现整体光谱能量分布和分子发射特征，但大幅低估了中红外原子禁线的强度，导致合成光谱以分子发射为主。抑制分子不透明度的实验未能恢复禁线；相反，发射峰迁移到 2 微米附近的 Co 和 Fe 跃迁。我们将这种差异归因于碰撞速率约束不佳，以及当前抛射体模型中铁族物质可能过量。12.8 微米处的显著特征无法用[Ne II] 12.81 微米线很好地解释，表明该 12.8 微米特征可能主要源于[Fe III]。CO、SiO 和稳定镍的存在，加上未探测到氖，对 SN Iax 前身系统的总抛射体质量和核合成产额施加了严格约束。
英文摘要
We report JWST spectra and photometry of the underluminous SN Iax 2024vjm obtained 202.8 restframe days post-explosion. The spectrum exhibits a rich set of forbidden lines from low-ionization, intermediate-mass, and iron-group elements, notably the [Ni II] 6.64 micron resonance line, which is a direct indicator of stable nickel. Strong CO and SiO emission is detected alongside a warm dust continuum; the spectral properties are consistent with pre-existing rather than newly formed dust. Synthetic spectra were computed with the generalized stellar atmospheres code PHOENIX/1D using simplified ejecta models. The models reproduce the overall spectral energy distribution and the molecular emission features reasonably well, but substantially underestimate the strength of the mid-infrared atomic forbidden lines, leaving the synthetic spectrum dominated by molecular emission. Experiments in which the molecular opacity is suppressed do not recover the forbidden lines; instead, the emission peak migrates to Co and Fe transitions near 2 microns. We attribute this discrepancy to poorly constrained collisional rates and possibly to an excess of iron-group material in the current ejecta models. A prominent feature at 12.8 microns is not well accounted for by the [Ne II] 12.81 micron line, indicating that the 12.8 micron feature may be largely due to [Fe III]. The presence of CO, SiO, and stable nickel together with the non-detection of neon places tight constraints on the total ejecta mass and the nucleosynthetic yields of SNe Iax progenitor systems.
Comments19 pages, 10 figures, to appear in ApJ (Letters)
