ADVECTION-DOMINATED ACCRETION - A SELF-SIMILAR SOLUTION
ADVECTION-DOMINATED ACCRETION - A SELF-SIMILAR SOLUTION
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DOI：
10.1086/187381
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发表时间：
1994-06-10
影响因子：
4.9
通讯作者：
YI, I
中科院分区：
文献类型：
--
作者：
NARAYAN, R;YI, I
我们考虑粘性旋转吸积流，其中大部分粘性耗散的能量以熵的形式存储，而不是被辐射。当光学厚度很小或很大时，这种以平流为主的流动可能会发生。我们得到了一族自相似解，其中吸积气体的温度接近维里，流动是准球形的。气体的自转速度远低于开普勒角速度；因此，这种流动中的中心恒星在达到分裂极限之前很久就会停止自转。此外，伯努利参数为正，这意味着以平流为主的流动很容易产生外流。对流可能存在于许多这样的流动中，如果存在，将倾向于加强上述影响。我们认为，平流主导的吸积作用可以解释吸积恒星的缓慢自转速度，以及吸积系统中广泛存在的流出和喷流现象。
We consider viscous rotating accretion flows in which most of the viscously dissipated energy is stored as entropy rather than being radiated. Such advection-dominated flows may occur when the optical depth is either very small or very large. We obtain a family of self-similar solutions where the temperature of the accreting gas is nearly virial and the flow is quasi-spherical. The gas rotates at much less than the Keplerian angular velocity; therefore, the central stars in such flows will cease to spin up long before they reach the break-up limit. Further, the Bernoulli parameter is positive, implying that advection-dominated flows are susceptible to producing outflows. Convection is likely in many of these flows and, if present, will tend to enhance the above effects. We suggest that advection-dominated accretion may provide an explanation for the slow spin rates of accreting stars and the widespread occurrence of outflows and jets in accreting systems.