论文标题
通过行星积聚种植卵石积聚的种子
Growing the seeds of pebble accretion through planetesimal accretion
论文作者
论文摘要
我们探索了行星胚胎通过行星胚胎的增长，直到所谓的山丘变换量在卵石积聚效率上有效。流动不稳定性形成的过渡质量和行星的特征质量随着与恒星距离的增加而增加。我们开发了一个模型，用于嵌入大型行星（胚胎）的生长模型，该行星（胚胎）嵌入在流媒体不稳定性中形成的较小行星人群中。该模型包括胚胎的碰撞质量生长，地球的碎片，所有相关物体的速度演变以及细丝的粘性扩散。我们发现，仅在圆盘内部区域的原星盘的寿命中，胚胎会在细丝中积聚所有可用的材料。相比之下，我们发现光盘外部几乎没有或没有5--10 AU的外部生长。总体而言，我们的结果表明，在巨型行星形成的原球星盘区域中，行星碰撞增长的时间很长。因此，为了在冷轨道上形成巨型行星，卵石积聚必须直接作用于行星标本初始质量功能中最大的物体，而相互碰撞几乎没有帮助。
We explore the growth of planetary embryos by planetesimal accretion up to and beyond the point where pebble accretion becomes efficient at the so-called Hill-transition mass. Both the transition mass and the characteristic mass of planetesimals formed by the streaming instability increase with increasing distance from the star. We developed a model for the growth of a large planetesimal (embryo) embedded in a population of smaller planetesimals formed in a filament by the streaming instability. The model includes in a self-consistent way the collisional mass growth of the embryo, the fragmentation of the planetesimals, the velocity evolution of all involved bodies, as well as the viscous spreading of the filament. We find that the embryo accretes all available material in the filament during the lifetime of the protoplanetary disc only in the inner regions of the disc. In contrast, we find little or no growth in the outer parts of the disc beyond 5--10 AU. Overall, our results demonstrate very long timescales for collisional growth of planetesimals in the regions of the protoplanetary disc where giant planets form. As such, in order to form giant planets in cold orbits, pebble accretion must act directly on the largest bodies present in the initial mass-function of planetesimals with little or no help from mutual collisions.
