论文标题
白矮人的二进制文件建议一个普通的信封效率$α\ sim 1/3 $
White dwarf binaries suggest a common envelope efficiency $α\sim 1/3$
论文作者
论文摘要
共同的包膜（CE）进化对于创建短期二进制和相关的天体物理事件至关重要，可以通过这种二进制组的形成历史的反向建模来限制。通过分析具有低质量初次的良好约束的白矮人（WD）二进制样本（7种黯然失色的双WDS，2个非销售的双WDS，1 WD-Brown Dwwarf），我们估计CE能源效率$α_ {\ rm {CE {CE}} $需要固定水力发生。我们使用HE和联合核心WD模型的网格来确定与每个主要WD半径和温度相匹配的质量和冷却年龄。假设引力波驱动的轨道衰减，我们随后计算了CE后轨道时期相关的范围。通过将WD模型映射到红色巨型祖细胞之星的网格，我们确定了启动CE Evolution的总包膜结合能和可能的轨道周期，从而限制了$α_ {\ rm CE} $。假设He -core WD具有0.9-2.0 $ m_ \ odot $的祖先，我们发现$α_ {\ rm ce} \！ \ sim \！ 0.2-0.4 $与我们建模的每个系统一致。 $α_ {\ rm {ce}} $的值明显更高，对于更高的质量祖细胞和共同核心WDS所需，因此认为这些情况不太可能。我们的值主要与以前对旧金车后二进制的研究一致，它们暗示了产生HE-CORE WD的CE事件的恒定和低包膜射血效率。
Common envelope (CE) evolution, which is crucial in creating short period binaries and associated astrophysical events, can be constrained by reverse modeling of such binaries' formation histories. Through analysis of a sample of well-constrained white dwarf (WD) binaries with low-mass primaries (7 eclipsing double WDs, 2 non-eclipsing double WDs, 1 WD-brown dwarf), we estimate the CE energy efficiency $α_{\rm{CE}}$ needed to unbind the hydrogen envelope. We use grids of He- and CO-core WD models to determine the masses and cooling ages that match each primary WD's radius and temperature. Assuming gravitational wave-driven orbital decay, we then calculate the associated ranges in post-CE orbital period. By mapping WD models to a grid of red giant progenitor stars, we determine the total envelope binding energies and possible orbital periods at the point CE evolution is initiated, thereby constraining $α_{\rm CE}$. Assuming He-core WDs with progenitors of 0.9 - 2.0 $M_\odot$, we find $α_{\rm CE} \! \sim \! 0.2-0.4$ is consistent with each system we model. Significantly higher values of $α_{\rm{CE}}$ are required for higher mass progenitors and for CO-core WDs, so these scenarios are deemed unlikely. Our values are mostly consistent with previous studies of post-CE WD binaries, and they suggest a nearly constant and low envelope ejection efficiency for CE events that produce He-core WDs.
