缓慢白矮星合并：铁元素以外新型银河系来源
摘要
我们今天在太阳系中观测到的最重的稳定元素的天体物理起源仍不完全明了。最近的研究表明，H-摄取的白矮星（WD）在二进制系统中爆炸为Ia型超新星时，可能是铁元素以外的有效p-过程来源。然而，观测证据与星体模型挑战了此类事件所需的发生频率。在本工作中，我们计算了缓慢合并的碳-氧WD的演化与核合过程。当我们的模型在合并阶段接近查尔丹赫克量时，22Ne(a,n)25Mg中性子源反应在主要WD的外部层中被激活，在此区域，来自次级WD的碳-rich物料通过12C+12C反应燃烧，该反应通过12C(12C,α)20Ne通道提供必要的α粒子。 resulting neutron capture abundance distribution closely resembles a weak s-process one and peaks at Zr, which is overproduced by a factor of 30 compared to solar. The mass of the most external layers enriched in first-peak s-process elements crucially depends on the 12C+12C reaction rate, ranging between 0.05 Msun and ~0.1 Msun. These results indicate that slow white dwarf mergers can efficiently produce the lightest p-process isotopes (such as 74Se, 78Kr, 84Sr, 92Mo and 94Mo) via γ-induced reactions if they explode via a delayed detonation mechanism, or eject the unburned external layers highly enriched in first peak s-process elements in the case of a pure deflagration. In both cases, we propose for the first time that slow WD mergers in binary systems may be a new relevant source for elements heavier than iron.
引用
@article{arxiv.2601.07151,
title = {Slow White Dwarf Mergers as a New Galactic Source of Trans-Iron Elements},
author = {Umberto Battino and Claudia Lederer-Woods and Claudia Travaglio and Friedrich Konrad Röpke and Brad Gibson},
journal= {arXiv preprint arXiv:2601.07151},
year = {2026}
}
备注
Published on EPJ Web of Conferences