Fragmentation of Gravitationally Unstable Gaseous Protoplanetary Disks with Radiative Transfer
Fragmentation of Gravitationally Unstable Gaseous Protoplanetary Disks with Radiative Transfer
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引力不稳定气态原行星盘的辐射传输破碎
DOI：
10.1086/518433
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
J. Wadsley
中科院分区：
文献类型：
--
作者：
L. Mayer;G. Lufkin;T. Quinn;J. Wadsley
我们报道了首次对具有辐射传输的引力不稳定原行星盘进行3DSPH模拟的结果。我们采用了流量受限的扩散方案，这是由于大部分磁盘的高不透明度所证明的。圆盘的光学薄面冷却为黑体。我们发现，可能会出现质量接近木星质量的引力束缚团块。碎裂似乎是由垂直对流运动驱动的，这些运动能够在10AU的时间尺度上将热量从磁盘中面传输到其表面，时间尺度仅为40年左右。光盘在光学薄表面的冷却效率较大或较小，可通过影响决定是否发生对流的垂直温度分布以及通过调节从光学薄区向过密区的吸积来促进或抑制碎裂。我们还发现，由于压缩加热减少，平均分子量μ越高，碎裂的可能性就越大。只有质量为>；0.12M☉、μ≥为2.4M的圆盘才能碎裂，就像预期的那样，金属丰度与太阳相当或更高的气体。
We report on the results of the first 3D SPH simulations of gravitationally unstable protoplanetary disks with radiative transfer. We adopt a flux-limited diffusion scheme justified by the high opacity of most of the disk. The optically thin surface of the disk cools as a blackbody. We find that gravitationally bound clumps with masses close to a Jupiter mass can arise. Fragmentation appears to be driven by vertical convective-like motions capable of transporting the heat from the disk midplane to its surface on a timescale of only about 40 years at 10 AU. A larger or smaller cooling efficiency of the disk at the optically thin surface can promote or stifle fragmentation by affecting the vertical temperature profile, which determines whether convection can happen or not, and by regulating accretion from optically thin regions toward overdense regions. We also find that the chances of fragmentation increase for a higher mean molecular weight, μ, since compressional heating is reduced. Only disks with masses >0.12 M☉ and with μ ≥ 2.4, as expected for gas with a metallicity comparable to solar or higher, can fragment.