论文标题
两个碳氧气核心白色矮人合并残留的进化模型
Evolutionary Models for the Remnant of the Merger of Two Carbon-Oxygen Core White Dwarfs
论文作者
论文摘要
我们构建了两个碳 - 氧（CO）核心白色矮人（WDS）的合并残留的进化模型。由于总质量在$ 1-2 {\ rm m_ \ odot} $中，这些残余物可能会留下单个巨大的WD，或者将合并引起的倒塌倒入中子星（NS）。在达到最终命运的途中，这些对象通常会经历$ \ sim 10 $ kyr发光巨型阶段，如果仍然有足够的氦气设置稳定的壳燃烧配置，则可能会扩展。在此阶段，不确定但可能显着的质量损失率会影响最终的残余质量和命运（WD或NS）。我们发现，WD的初始CO核心组成将最终质量$ \ gtrsim 1.05 {\ rm m_ \ odot} $的残留物转换为氧气蛋白（一个）。这意味着通过合并形成的单个WD中的CO核心 /一个核心过渡发生在与单星星降低的WDS相似的质量，因此WD-WD合并并不自然地提供产生超质量的co核WDS的途径。当残留物与紧凑型配置合同时，它经历了“瓶颈”，从而设定了可以保留的特征性总角动量。该极限预测由WD-WD合并形成的单个WD的旋转周期在WD冷却轨道上的旋转周期约为10-20美元。同样，它预测残留物可以崩溃形成旋转周期$ \ sim 10 $ ms的NSS。
We construct evolutionary models of the remnant of the merger of two carbon-oxygen (CO) core white dwarfs (WDs). With total masses in the range $1-2 {\rm M_\odot}$, these remnants may either leave behind a single massive WD or undergo a merger-induced collapse to a neutron star (NS). On the way to their final fate, these objects generally experience a $\sim 10$ kyr luminous giant phase, which may be extended if sufficient helium remains to set up a stable shell-burning configuration. The uncertain, but likely significant, mass loss rate during this phase influences the final remnant mass and fate (WD or NS). We find that the initial CO core composition of the WD is converted to oxygen-neon (ONe) in remnants with final masses $\gtrsim 1.05 {\rm M_\odot}$. This implies that the CO core / ONe core transition in single WDs formed via mergers occurs at a similar mass as in WDs descended from single stars, and thus that WD-WD mergers do not naturally provide a route to producing ultra-massive CO-core WDs. As the remnant contracts towards a compact configuration, it experiences a "bottleneck" that sets the characteristic total angular momentum that can be retained. This limit predicts single WDs formed from WD-WD mergers have rotational periods of $\approx 10-20$ min on the WD cooling track. Similarly, it predicts remnants that collapse can form NSs with rotational periods $\sim 10$ ms.
