On the orbital evolution of binaries with circumbinary discs
On the orbital evolution of binaries with circumbinary discs
复制标题
具有环双星盘的双星的轨道演化
DOI：
10.1051/0004-6361/202038548
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发表时间：
2020
影响因子：
6.5
通讯作者：
C. Nixon
中科院分区：
文献类型：
--
作者：
Ryan Heath;C. Nixon
通常认为，环联星盘会随着时间的推移通过轨道共振介导的重力扭矩从联星轨道中吸收角动量和能量。这一过程导致双星轨道随时间的收缩，并且在各种天体物理学背景下都很重要，包括恒星双星的轨道演化，原行星盘中行星的迁移，以及黑洞双星（恒星和超大质量）的演化。致密双星的合并为宇宙中的引力波提供了一个来源。最近，几个研究小组报告了环双星盘的数值模拟，得出了相反的结果，发现双星随着时间的推移而膨胀。在这里，我们认为，这一结果主要是由于模拟参数的选择，数值的原因，这不同于现实的光盘参数在许多情况下。我们提供的物理参数，然后证明与三维流体动力学模拟，厚（高压，高粘度）光盘驱动器足够的吸积高角动量材料，迫使二元膨胀，而在更现实的情况下薄（低压，低粘度）光盘有较少的吸积和二元收缩。在后一种情况下，潮汐通常将角动量和能量从旋转速度更快的物体（双星）转移到旋转速度较低的物体（圆盘），是圆盘双星演化的主要驱动力。这会导致二进制文件缩小。因此，我们的结论是，对于常见的环双星盘参数，非极端质量比的双星预计会随着时间的推移而缩小。双星系统的膨胀可能发生在盘的粘度异常高的情况下，这可能发生在非常厚的盘中，例如，环行星盘，超爱丁顿活动星系核，或被中央原恒星加热的被动原恒星盘的外部区域。我们还提供了一些简化的问题，这是普遍存在的文献中，通常是为了数值方便的影响进行了讨论，对光盘二进制的演变。
Circumbinary discs are generally thought to take up angular momentum and energy from the binary orbit over time through gravitational torques that are mediated by orbital resonances. This process leads to the shrinkage of the binary orbit over time, and it is important in a variety of astrophysical contexts including the orbital evolution of stellar binaries, the migration of planets in protoplanetary discs, and the evolution of black hole binaries (stellar and supermassive). The merger of compact object binaries provides a source of gravitational waves in the Universe. Recently, several groups have reported numerical simulations of circumbinary discs that yield the opposite result, finding that the binary expands with time. Here we argue that this result is primarily due to the choice of simulation parameters, made for numerical reasons, which differ from realistic disc parameters in many cases. We provide physical arguments, and then demonstrate with 3D hydrodynamical simulations, that thick (high pressure, high viscosity) discs drive sufficient accretion of high angular momentum material to force binary expansion, while in the more realistic case of thin (low pressure, low viscosity) discs there is less accretion and the binary shrinks. In the latter case, tides, which generally transfer angular momentum and energy from the more rapidly rotating object (the binary) to the less rapidly rotating object (the disc), are the dominant driver of disc-binary evolution. This causes the binary to shrink. We therefore conclude that for common circumbinary disc parameters, binaries with non-extreme mass ratios are expected to shrink over time. Expansion of the binary can occur if the disc viscosity is unusually high, which may occur in the very thick discs encountered in, for example, circumplanetary discs, super-Eddington AGN, or the outer regions of passive protostellar discs that are heated by the central protostar. We also provide discussion of the impact that some simplifications to the problem, that are prevalent in the literature and usually made for numerical convenience, have on the disc-binary evolution.
DOI：
10.3847/1538-4357/aadae5
发表时间：
2017-02
期刊：
The Astrophysical Journal
影响因子：
--
作者：
B. McKernan;K. Ford;J. Bellovary;N. Leigh;Z. Haiman;B. Kocsis;W. Lyra;M. M. Low-M.;B. Metzger
通讯作者：
B. McKernan;K. Ford;J. Bellovary;N. Leigh;Z. Haiman;B. Kocsis;W. Lyra;M. M. Low-M.;B. Metzger
双星在薄吸积盘中的气体驱动吸入
DOI：
10.3847/1538-4357/aba432
发表时间：
2020
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Tiede, Christopher;Zrake, Jonathan;MacFadyen, Andrew;Haiman, Zoltan
通讯作者：
Haiman, Zoltan
影响因子：
4.8
作者：
Yi-Lei Tang;A. MacFadyen;Z. Haiman
通讯作者：
Yi-Lei Tang;A. MacFadyen;Z. Haiman