AI 中文总结
本研究通过多波段测光和光谱分析，将邻近长时标超新星 SN 2024afyu 识别为强对不稳定性超新星候选体，其宽光变曲线、大硫质量等特征难以用其他机制解释。
AI 中文摘要
对不稳定性超新星（PISNe）是由电子-正电子对产生所引发的、对非常大质量恒星爆炸的理论预言。许多暂现源被提出作为 PISN 候选体，但至今没有一个提供对该爆炸机制的明确确认。星云发射线的预言强度为检验 PISN 情景提供了有力手段。我们研究了 SN 2024afyu 的本质，这是一颗邻近（z = 0.0085）、长时标（trise = 85 ± 11.7 天）且具有特殊光谱演化的超新星，旨在确定其供能机制。我们分析了从爆炸后不久到星云阶段（峰值后约 500 天）的多波段测光和光学及近红外光谱。除了 [Ca II] 特征的早期出现外，我们还识别出若干硫和硅发射线，并据此估算了电子温度和元素质量。SN 2024afyu 的 56Ni 质量推断约为 0.4 至 1.0 太阳质量，硫质量约为 3 太阳质量，显著大于传统核坍缩爆炸的预期。SN 2024afyu 在测光上与其他提出的 PISNe 相似（尽管更暗，M_Peak(r) = -18.9 ± 0.04 等），但在光谱上却截然不同。然而，现有的 PISN 模型大致重现了若干关键特征，包括整体光谱外观和宽测光演化。SN 2024afyu 是一个强有力的 PISN 候选体，因为其他替代情景难以解释宽光变曲线、大中等质量元素丰度和总体光谱演化的组合。观测与当前可用理论模型之间的差异凸显了需要进行新的 PISN 计算，涵盖更宽的前身星质量、金属丰度、混合方案和星周环境范围。
英文摘要
Pair-instability supernovae (PISNe) are the predicted explosions of very massive stars triggered by electron-positron pair production. Numerous transients have been proposed as PISN candidates, yet none has provided unambiguous confirmation of this explosion mechanism. The predicted strengths of nebular emission lines offer a powerful means of testing the PISN scenario. We investigate the nature of SN 2024afyu, a nearby (z = 0.0085), long-lived (trise = 85 +- 11.7 days) SN with peculiar spectral evolution, with the aim of identifying its powering mechanism. We analyse multi-band photometry and optical and near-infrared spectroscopy from shortly after explosion to the nebular phase (around 500 days past peak). Besides early appearance of [Ca II] features, we identify a number of sulfur and silicon emission lines, for which we estimate electron temperatures and elemental masses. SN 2024afyu has an inferred 56Ni mass of around 0.4 to 1.0 solar masses and an inferred sulfur mass of the order of 3 solar masses, substantially larger than expected for conventional core-collapse explosions. SN 2024afyu is photometrically similar (although fainter, M_Peak(r) = -18.9 +- 0.04 mag) but spectroscopically distinct to other proposed PISNe. Yet, existing PISN models broadly reproduce several key characteristics, including the overall spectral appearance and broad photometric evolution. SN 2024afyu is a strong PISN candidate, since alternative scenarios would struggle to explain the combination of broad light curve, large intermediate-mass-element abundance, and general spectroscopic evolution. The discrepancies between the observations and currently available theoretical models highlight the need for new PISN calculations spanning a wider range of progenitor masses, metallicities, mixing prescriptions, and circumstellar environments.
Comments29 pages, 21 figures
