Flux-limited Diffusion Approximation Models of Giant Planet Formation by Disk Instability
Flux-limited Diffusion Approximation Models of Giant Planet Formation by Disk Instability
复制标题
盘不稳定性引起的巨行星形成的通量限制扩散近似模型
DOI：
10.1086/533496
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
A. Boss
中科院分区：
文献类型：
--
作者：
A. Boss
为了解释太阳系外行星系统中发现的整个巨行星范围，似乎需要核心吸积和盘不稳定性作为形成机制。盘的不稳定性是基于在重力轻微不稳定的原行星盘中形成团块。只有当这些团块能够通过对流和辐射冷却的结合失去热能时，它们才有望收缩并存活下来，成为原行星。在这里，我们提出了几个新的自引力原行星盘的三维辐射流体动力学模型，其中辐射传递是在通量限制扩散近似中处理的。我们表明，虽然通量限制模型导致比没有通量限制器的扩散近似模型更高的中面温度，但温度差异似乎不够高，不足以对自重力团块的形成产生任何显着影响。无论有或没有通量限制器，自重力团块都会在模型中快速形成。这些模型表明，不同群体的盘不稳定性数值模型产生不同结果的原因不能仅仅归因于辐射传输的处理，而似乎是由一系列数值效应和假设引起的。鉴于至少在某些太阳系外行星上存在盘不稳定性的观测必要性，这些模型意味着盘不稳定性仍然是一种可行的巨行星形成机制。
Both core accretion and disk instability appear to be required as formation mechanisms in order to explain the entire range of giant planets found in extrasolar planetary systems. Disk instability is based on the formation of clumps in a marginally gravitationally unstable protoplanetary disk. These clumps can only be expected to contract and survive to become protoplanets if they are able to lose thermal energy through a combination of convection and radiative cooling. Here we present several new three-dimensional, radiative hydrodynamics models of self-gravitating protoplanetary disks, where radiative transfer is handled in the flux-limited diffusion approximation. We show that while the flux-limited models lead to higher midplane temperatures than in a diffusion approximation model without the flux limiter, the difference in temperatures does not appear to be sufficiently high to have any significant effect on the formation of self-gravitating clumps. Self-gravitating clumps form rapidly in the models both with and without the flux limiter. These models suggest that the reason for the different outcomes of numerical models of disk instability by different groups cannot be attributed solely to the handling of radiative transfer, but rather appears to be caused by a range of numerical effects and assumptions. Given the observational imperative to have disk instability form at least some extrasolar planets, these models imply that disk instability remains as a viable giant planet formation mechanism.