Enrichment of the Dust-to-Gas Mass Ratio in Bondi/Jeans Accretion/Cloud Systems due to Unequal Changes in Dust and Gas Incoming Velocities

The ratio of the Bondi and Jeans lengths is used to develop a cloud-accretion model that describes both an inner Bondi-type regime where gas pressure is balanced by the gravity of a central star and an outer Jeans-type regime where gas pressure is balanced by gas self-gravity. The gas density profile provided by this model makes a smooth transition from a wind-type inner solution to a Bonnor-Ebert-type outer solution. It is shown that high-velocity dust impinging on this cloud will tend to pile up due to having a different velocity profile from gas so that the dust-to-gas ratio is substantially enriched above the 1% interstellar medium (ISM) level.

邦迪长度和金斯长度的比值被用于建立一个吸积云模型，该模型描述了内部的邦迪型区域（其中气体压力由中心恒星的引力平衡）以及外部的金斯型区域（其中气体压力由气体自引力平衡）。这个模型所提供的气体密度分布从风型内部解平滑过渡到博纳 - 埃伯特型外部解。研究表明，撞击该云的高速尘埃由于其速度分布与气体不同，往往会堆积起来，使得尘埃与气体的比例大大高于星际介质（ISM）1%的水平。