近距离双星中的γ-仙王座再访
Disks in close binary stars: γ-Cephei revisited
摘要：
近距离双星（$a_{bin} < 20$ au）是已知的行星，但行星形成不太可能在这样的系统中成功。研究近距离双星中圆盘的动力学可以帮助理解这些行星是如何形成的。我们研究的影响，数值和物理参数上的动态磁盘紧密的二进制文件。我们使用的$γ$ -Cephei系统作为一个例子，并专注于磁盘的数量，如磁盘偏心率和进动率作为指标的动态状态的磁盘。我们模拟磁盘在密切的二进制文件进行二维辐射流体动力学模拟使用修改后的版本的法戈代码。首先，我们对不同的数值参数进行了参数研究，以确认我们的结果是稳健的。在第二部分中，我们研究了不同质量和不同粘度对圆盘动力学的影响。以前对密近双星中辐射盘的研究使用了太低的分辨率和太小的模拟域，这影响了盘的动力学。我们发现，辐射盘在紧密的双星，初始化阶段后，成为偏心的平均偏心率在0.06至0.27之间，并显示一个缓慢的逆行进动周期范围从$4 - 40T_{bin}$二次依赖于磁盘的平均纵横比。一般来说，圆盘表现出连贯的、刚性的进动，然而，通过不透明度定律的改变，减少圆盘的整体偏心率，这种进动可以被打破。
英文摘要：
Close binaries ($a_{bin} < 20$ au) are known to harbor planets, yet planet formation is unlikely to succeed in such systems. Studying the dynamics of disks in close binaries can help to understand how those planets could have formed. We study the impact that numerical and physical parameters have on the dynamics of disks in close binaries. We use the $γ$-Cephei system as an example and focus on disk quantities such as disk eccentricity and the precession rate as indicators for the dynamical state of the disks. We simulate disks in close binaries by performing two-dimensional radiative hydrodynamical simulations using a modified version of the Fargo code. First, we perform a parameter study for different numerical parameters to confirm that our results are robust. In the second part, we study the effects of different masses and different viscosities on the disks' dynamics. Previous studies on radiative disks in close binaries used too low resolutions and too small simulation domains, which impacted the disk's dynamics. We find that radiative disks in close binaries, after an initialization phase, become eccentric with mean eccentricities between 0.06 to 0.27 and display a slow retrograde precession with periods ranging from $4 - 40T_{bin}$ which depends quadratically on the disk's mean aspect ratio. In general, the disks show a coherent, rigid precession which can be broken, however, by changes in the opacity law reducing the overall eccentricity of the disk.
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