发表机构
The Pennsylvania State University; Institute of Science Tokyo（宾夕法尼亚州立大学; 东京科学大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过多波段观测揭示IIb型超新星SN2025aico中$^{56}$Ni有限混合、抛射物不对称及新尘埃形成，连接了前身星演化与爆炸物理。
AI 中文摘要
剥离包层超新星为研究大质量恒星如何失去其外层、混合放射性物质、产生尘埃以及不对称爆炸提供了窗口。我们展示了SN~2025aico（LEDA~35384中的一颗IIb型超新星）的光学、近红外（NIR）和中红外（MIR）观测。我们的光谱序列覆盖爆炸后$+1$至$+167$天，追踪了其从同时呈现氢和氦特征的光球层阶段，到显著的氦发射，最终到星云阶段抛射物的演化过程。利用He I $1.083$和$2.0581\\,\mu$m跃迁，我们研究了富氦物质的运动学和几何结构。两条跃迁均表现出三阶段、非单调的速度演化：初始快速下降，随后上升，最终趋于平稳。我们将这一行为解释为$^{56}$Ni有限向外混合的证据，使得放射性能量沉积随着抛射物的膨胀逐渐到达外层富氦区域，产生激发氦的非热电子。约100天后，两条NIR He I跃迁均发展出双峰发射轮廓。氧发射中的类似结构表明抛射物存在不对称性。与其他超新星的比较表明，这种结构与爆炸能量之间可能存在初步关联，可能涉及核心坍缩与爆炸之间的延迟。在$+124.4$天时偶然获得的JWST观测揭示了红外过量。建模倾向于抛射物中新形成的暖（约800--1500K）碳尘埃，以及可能与先前存在的星周物质有关的较冷碳或硅酸盐尘埃。SN~2025aico展示了连续的光学至MIR观测如何将前身星演化、爆炸物理、抛射物几何和尘埃产生联系起来。
英文摘要
Stripped-envelope supernovae provide a window into how massive stars lose their layers, mix radioactive material, produce dust, and explode asymmetrically. We present optical, near-infrared (NIR), and mid-infrared (MIR) observations of SN~2025aico, a Type~IIb supernova in LEDA~35384. Our spectroscopic sequence, spanning $+1$ to $+167$ d after explosion, follows its evolution from a photospheric phase exhibiting both hydrogen and helium features to prominent helium emission and, ultimately, nebular-phase ejecta. Using He I $1.083$ and $2.0581\,μ$m transitions, we investigated the kinematics and geometry of the helium-rich material. Both transitions exhibit a three-phase, non-monotonic velocity evolution: an initial rapid decline, a subsequent increase, and an eventual plateau. We interpret this behavior as evidence for limited outward mixing of $^{56}$Ni, such that radioactive energy deposition reaches the outer helium-rich ejecta progressively as the ejecta expand, producing the non-thermal electrons responsible for helium excitation. After $\sim100$ d, both NIR He I transitions develop double-peaked emission profiles. Similar structure in the oxygen emission indicates ejecta asymmetry. Comparison with other supernovae suggests a tentative connection between this structure and explosion energy, potentially linked to the delay between core collapse and explosion. Serendipitous JWST observations at $+124.4$d reveal an infrared excess. Modeling favors warm ($\sim800$--$1500$K) carbon dust newly formed in the ejecta, together with cooler carbon or silicate dust likely associated with pre-existing circumstellar material. SN~2025aico demonstrates how continuous optical-to-MIR observations can connect progenitor evolution, explosion physics, ejecta geometry, and dust production.
Comments30 pages, 12 figures
