A transition in circumbinary accretion discs at a binary mass ratio of 1:25
A transition in circumbinary accretion discs at a binary mass ratio of 1:25
复制标题
DOI：
10.1093/mnras/stw792
复制
发表时间：
2016-07-01
影响因子：
4.8
通讯作者：
Farris, Brian
中科院分区：
文献类型：
--
作者：
D'Orazio, Daniel J.;Haiman, Zoltan;Farris, Brian
本文在限制性三体问题（R3 Bp）的框架下，通过数值求解粘性流体动力学的高度积分方程，研究了环双星吸积盘。改变二进制的质量比，我们发现一个显着的变化，在质量比q = M-s/M-p附近的光盘的行为类似于0.04。对于质量比q = 0.04以上，解决方案的流体动力流过渡从稳定的，强烈波动;一个狭窄的环形间隙的表面密度周围的次级的轨道变化到一个中空的中央空腔;和空间对称性丢失，导致在一个不平衡的光盘。这种相变与R3 Bp的L4和L5平衡点附近不存在稳定轨道的质量比相一致。使用DISCO代码，我们发现，对于薄盘，其中的间隙或空腔可以保持开放，过渡的质量比是相对不敏感的光盘粘度和压力。q = 0.04的转变与星系核中心的大质量黑洞双星+盘系统的演化有关，也与年轻的恒星双星和可能围绕棕矮星的行星有关。
We study circumbinary accretion discs in the framework of the restricted three-body problem (R3Bp) and via numerically solving the height-integrated equations of viscous hydrodynamics. Varying the mass ratio of the binary, we find a pronounced change in the behaviour of the disc near mass ratio q = M-s/M-p similar to 0.04. For mass ratios above q = 0.04, solutions for the hydrodynamic flow transition from steady, to strongly fluctuating; a narrow annular gap in the surface density around the secondary's orbit changes to a hollow central cavity; and a spatial symmetry is lost, resulting in a lopsided disc. This phase transition is coincident with the mass ratio above which stable orbits do not exist around the L4 and L5 equilibrium points of the R3Bp. Using the DISCO code, we find that for thin discs, for which a gap or cavity can remain open, the mass ratio of the transition is relatively insensitive to disc viscosity and pressure. The q = 0.04 transition has relevance for the evolution of massive black hole binary+disc systems at the centres of galactic nuclei, as well as for young stellar binaries and possibly planets around brown dwarfs.