论文标题
在自我散热磁盘中直接形成行星胚胎
Direct Formation of Planetary Embryos in Self-Gravitating Disks
论文作者
论文摘要
在与中央恒星的大分离处发现了巨型行星。此外，大量的年轻杂质磁盘在大轨道分离处具有气体和/或防尘隙，可能由嵌入的行星物体驱动。然而，要通过磁盘寿命内的核心积聚形成大型行星，但是，需要早期的固体卵石和浓积胶。年轻的原球磁盘可能是自我磨碎的，这些引力磁盘可能有效地将固体物质浓缩在由螺旋波驱动的中平面上。我们运行带有拉格朗日粉尘颗粒引力磁盘的3D局部流体动力学模拟，以确定粒子和气体自我重力是否会导致密集的固体形成，从而播种后来的行星形成。当包括灰尘颗粒之间的自重时，大小$ \ mathrm {st} = 0.1 $至$ 1 $浓缩的固体在引力尿布螺旋形中，并在自己的自我重力下崩溃，最多可达几个$ m _ {\ oplus} $，在广阔的Orbits中。灰尘最有效地漂移的模拟，$ \ mathrm {st} = 1 $，形成最大的粒子云，而较小的灰尘粒子的模拟，$ \ mathrm {st} = 0.1 $，具有质量级的团块。当包括灰尘反应对气体的影响时，灰尘团会变得更小但数量更多。在磁盘的早期阶段存在大型固体，可以加速行星形成过程，尤其是在宽轨道分离下，并有可能解释远离中心恒星的行星和带有子结构的年轻原球磁盘。
Giant planets have been discovered at large separations from the central star. Moreover, a striking number of young circumstellar disks have gas and/or dust gaps at large orbital separations, potentially driven by embedded planetary objects. To form massive planets at large orbital separations through core accretion within disk lifetime, however, an early solid body to seed pebble and gas accretion is desirable. Young protoplanetary disks are likely self-gravitating, and these gravitoturbulent disks may efficiently concentrate solid material at the midplane driven by spiral waves. We run 3D local hydrodynamical simulations of gravitoturbulent disks with Lagrangian dust particles to determine whether particle and gas self-gravity can lead to the formation of dense solid bodies, seeding later planet formation. When self-gravity between dust particles is included, solids of size $\mathrm{St} = 0.1$ to $1$ concentrate within the gravitoturbulent spiral features and collapse under their own self-gravity into dense clumps up to several $M_{\oplus}$ in mass at wide orbits. Simulations with dust that drift most efficiently, $\mathrm{St}=1$, form the most massive clouds of particles, while simulations with smaller dust particles, $\mathrm{St}=0.1$, have clumps with masses an order of magnitude lower. When the effect of dust backreaction onto the gas is included, dust clumps become smaller by a factor of a few but more numerous. The existence of large solid bodies at an early stage of the disk can accelerate the planet formation process, particularly at wide orbital separations, and potentially explain planets distant from the central stars and young protoplanetary disks with substructures.
