原行星盘中瞬态加热事件导致多孔体中的冰沉积前沿
Ice Deposition Fronts In Porous Bodies From Transient Heating Events In a Protoplanetary Disk
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中文总结 AI 辅助
研究原行星盘中多孔体在瞬态加热事件下的冰沉积前沿，用一维质量和热传输模型模拟水等物质的升华与沉积，发现前沿形成及移动规律，其特性取决于孔径，还能改变多孔冰体地下形态和物理性质。
中文摘要 AI 辅助
我们使用一维质量和热传输模型，对嵌入原行星盘的多孔体在瞬态加热事件中的热流和气体传输进行数值积分。小冰粒受热时挥发物升华，使盘富含挥发性气体。多孔体进入该富挥发物热环境时，挥发性气体在其中扩散并在挥发物分压超过其蒸气压处沉积冰。我们模拟了水、二氧化碳和一氧化碳的升华和沉积前沿。模拟表明，随着物体升温，冰沉积前沿形成并向多孔体深处移动。初始干燥物体中沉积的星云气体量通常极低；但在初始含冰物体中，冰沉积前沿包含局部升华的挥发物，可使表面下薄层中的冰体积分数增加（达2倍）。我们发现冰沉积前沿的传播速度、强度和最终深度主要取决于孔径。我们提出星云加热事件可改变原行星盘中多孔冰体的地下形态和物理性质。
英文摘要
Using a 1D mass and heat transport model, we numerically integrate heat flow and gas transport in a porous body exposed to a transient heating event while embedded in a protoplanetary disk. When small icy grains are heated, volatiles sublimate, enriching the disk with volatile gases. When a porous body enters this heated, volatile-rich environment, volatile gases diffuse throughout the cool, porous body and deposit ice where the partial pressure of a volatile exceeds its vapor pressure. We simulate sublimation and deposition fronts of water, carbon dioxide, and carbon monoxide. Our simulations show that an ice deposition front forms and moves deeper into the porous body as the body warms. The amount of nebular gas deposited in an initially dry body is usually extremely low; however, in an initially icy body, an ice deposition front contains locally sublimated volatiles. In this case, the front can increase the ice volume fraction (by a factor of 2) in a thin layer below the surface. We find that the propagation speed, propagation strength, and final depth of an ice deposition front primarily depend on pore size. We propose that nebular heating events can alter the subsurface morphology and physical properties of porous icy objects embedded in a protoplanetary disk.
