Geometrical and physical properties of circumbinary discs in eccentric stellar binaries
Geometrical and physical properties of circumbinary discs in eccentric stellar binaries
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偏心恒星双星中环双星盘的几何和物理特性
DOI：
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发表时间：
2008
期刊：
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通讯作者：
L. Aguilar
中科院分区：
文献类型：
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作者：
B. Pichardo;L. Sparke;L. Aguilar
在以前的工作（Pichardo等人，2005），我们研究了稳定的配置拱星盘偏心双星系统。我们寻找“不变环”：闭合曲线（类似于与时间无关的势中的稳定周期轨道），随着二元轨道相位的变化而改变形状，因为其中的测试粒子在二元势的影响下移动。这种方法使我们能够确定稳定的配置时，压力是不重要的，和耗散的作用，只是为了防止气体云相互碰撞。我们现在将这项工作扩展到研究环双星圆盘的主要几何性质。我们已经研究了100多个案件的范围内偏心0 6 e 6 0.9，和质量比0.1 6 q 6 0.9。虽然气体动力学可能会施加进一步的限制，我们的研究设置较低的稳定边界的中心孔的大小在一个简单的和计算成本低的方式，与依赖于中心的偏心率和质量比的关系。我们扩展我们以前的研究，并专注于这些系统的一个重要组成部分：环双星盘。在环双星盘中，稳定轨道的半径可以容纳气体，但它是双星偏心率的函数。环双星盘的结构几乎是圆形的，偏心率艾德< 0.15，但是如果质量比不相等，盘偏离系统的质心。我们比较我们的结果与其他模型，并与观测的特定系统，如GG金牛座A，御夫座UY，HD 98800 B，北落师门，限制合理的参数的二进制。
In a previous work (Pichardo et al. 2005), we studied stable configurations for circumstellar discs in eccentric binary systems. We searched for “invariant loops”: closed curves (analogous to stable periodic orbits in time-independent potentials) that change shape with the binary orbital phase, as test particles in them move under the influence of the binary potential. This approach allows us to identify stable configurations when pressure forces are unimportant, and dissipation acts only to prevent gas clouds from colliding with one another. We now extend this work to study the main geometrical properties of circumbinary discs. We have studied more than 100 cases with a range in eccentricity 0 6 e 6 0.9, and mass ratio 0.1 6 q 6 0.9. Although gas dynamics may impose further restrictions, our study sets lower stable bounds for the size of the central hole in a simple and computationally cheap way, with a relation that depends on the eccentricity and mass ratio of the central binary. We extend our previous studies and focus on an important component of these systems: circumbinary discs. The radii for stable orbits that can host gas in circumbinary discs are sharply constrained as a function of the binary’s eccentricity. The circumbinary disc configurations are almost circular, with eccentricity ed < 0.15, but if the mass ratio is unequal the disk is offset from the center of mass of the system. We compare our results with other models, and with observations of specific systems like GG Tauri A, UY Aurigae, HD 98800 B, and Fomalhaut, restricting the plausible parameters for the binary.