The impact of recombination energy on simulations of the common-envelope binary interaction
The impact of recombination energy on simulations of the common-envelope binary interaction
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DOI：
10.1093/mnras/staa937
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发表时间：
2019-11
影响因子：
4.8
通讯作者：
T. Reichardt;O. De Marco-O.-De Marco-2124556154;R. Iaconi;L. Chamandy;D. Price
中科院分区：
文献类型：
--
作者：
T. Reichardt;O. De Marco-O.-De Marco-2124556154;R. Iaconi;L. Chamandy;D. Price
在共包层二元相互作用过程中，气体共包层的膨胀层发生了复合，由此产生的复合能被认为是导致包层抛射的一个因素。在这篇文章中，我们进行了模拟和不包括复合能的比较研究。我们使用两个不同的设置，包括0.88M和1.8M的⊙巨人，这两个之前已经被研究过，可以作为基准。在此过程中，我们得出结论：(I)最终的轨道分离不受状态方程(EOS)的选择的影响。换句话说，只解开一小部分包膜的模拟结果与那些由于复合能量而解开大得多的部分的模拟结果相似。(Ii)列表状态方程的采用导致了更大比例的非束缚包络，我们证明了其原因是复合能的释放。(Iii)被允许做功的氢复合能的分数应该是我们的绝热模拟所使用的分数的大约一半。然而，对于较重的恒星模拟，我们得出的结论是，是氦而不是氢的复合能解开了气体，我们确定所有的氦的复合能在包层中被加热并起作用。(V)膨胀的共同包络的外部区域可能会看到尘埃的形成。这种尘埃将促进被抛出的包膜的额外解离和形成轴对称的形态。
During the common-envelope binary interaction, the expanding layers of the gaseous common envelope recombine and the resulting recombination energy has been suggested as a contributing factor to the ejection of the envelope. In this paper, we perform a comparative study between simulations with and without the inclusion of recombination energy. We use two distinct setups, comprising a 0.88- and 1.8-M⊙ giants, that have been studied before and can serve as benchmarks. In so doing, we conclude that (i) the final orbital separation is not affected by the choice of equation of state (EoS). In other words, simulations that unbind but a small fraction of the envelope result in similar final separations to those that, thanks to recombination energy, unbind a far larger fraction. (ii) The adoption of a tabulated EoS results in a much greater fraction of unbound envelope and we demonstrate the cause of this to be the release of recombination energy. (iii) The fraction of hydrogen recombination energy that is allowed to do work should be about half of that which our adiabatic simulations use. (iv) However, for the heavier star simulation, we conclude that it is helium and not hydrogen recombination energy that unbinds the gas and we determine that all helium recombination energy is thermalized in the envelope and does work. (v) The outer regions of the expanding common envelope are likely to see the formation of dust. This dust would promote additional unbinding and shaping of the ejected envelope into axisymmetric morphologies.