Pebble Dynamics and Accretion Processes near planetary Embryos

行星胚胎附近的卵石动力学和吸积过程

• 批准号: 248759810
• 负责人: Professor Dr. Wilhelm Kley (†)
• 金额: --
• 依托单位: Abteilung Computational Physics
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/248759810?language=en
• 关键词: Pebble; Dynamics; Accretion; Processes; near

The planets in the Solar System and most of the observed extrasolar planetary systems are believed to have formed through a bottom-up process where growths starts from $\mu$m sized dust grains and proceeds through a long sequence of sticking collisions eventually to full grown planets, or planetary cores. For the outer, gaseous planets this is followed by the rapid accretion of gas that lead finally to Jupiter and Saturn. For this runaway gas accretion to occur a minimum core mass of several earth masses must have been accumulated. In the standard growth scenario, the time to reach this critical core mass is often longer than the typical lifetimes of protoplanetary disks. Hence, it constitutes a bottleneck in the overall planet formation process. Recently, the suggestion that it may be possible to overcome this constraint through the rapid accretion of cm-sized objects (pebbles) has attracted considerable attention.In this proposal we intend to analyze in detail the pebble accretion scenario under realistic astrophysical conditions and study the efficacy of the process with respect to the accretion timescale and heavy element enrichment. For that purpose we plan to calculate the dynamics of particles of different sizes around growing cores that are embedded in three-dimensional protoplanetary disks and calculate the accretion rate onto the core.

太阳系中的行星和大多数观测到的太阳系外行星系统被认为是通过自下而上的过程形成的，其中生长从微米大小的尘埃颗粒开始，经过一长串的粘着碰撞，最终形成完全生长的行星或行星核心。对于外层气态行星来说，随后是气体的快速吸积，最终形成木星和土星。为了发生这种失控的气体吸积，必须积累几个地球质量的最小核心质量。在标准增长情景中，达到这一临界核心质量的时间通常比原行星盘的典型寿命长。因此，它构成了整个行星形成过程的瓶颈。最近，通过厘米大小的物体（卵石）的快速吸积来克服这一限制的建议引起了相当大的关注。在这项建议中，我们打算详细分析现实天体物理条件下的卵石吸积场景，并研究该过程在吸积时间尺度和重元素富集方面的有效性。为此，我们计划计算嵌入三维原行星盘中的生长核心周围不同尺寸粒子的动力学，并计算核心上的吸积率。