论文标题
冰冷彗星粉尘颗粒的热物理模型
Thermophysical model for icy cometary dust particles
论文作者
论文摘要
语境。从核上抬起后，彗星灰尘颗粒会受到各种力。这些力定义了灰尘，轨迹，比对和碎片的动力学，这反过来又对昏迷的粒子分布产生了显着影响。目标。我们开发了一种数值的热物理模型，该模型适用于冰冷的彗星粉尘，以研究归因于冰的升华的力。方法。我们将最近引入的无冰粉尘颗粒的天气模型扩展到了含冰的灰尘。我们引入了一个额外的源术语，以占升华和凝结热的能量平衡方程。我们将直接模拟的蒙特卡洛方法与尘土飞扬的气体模型同时求解质量平衡方程和能量平衡方程。结果。数值测试表明，所提出的方法可用于覆盖从数十微米到厘米的尺寸范围的灰尘颗粒，计算成本中等。我们预测，对于假定的0.05的冰分分数为0.05，半径为r >> 1 mm，在1.35 au时，由于内部压力的堆积，可能会分解成MM大小的片段。 r <1 cm的颗粒在几分钟内失去冰块。因此，我们预计只有r> 1cm的颗粒才能表现出持续的升华和产生的升华力。
Context. Cometary dust particles are subjected to various forces after being lifted off the nucleus. These forces define the dynamics of dust, trajectories, alignment, and fragmentation, which, in turn, have a significant effect on the particle distribution in the coma. Aims. We develop a numerical thermophysical model that is applicable to icy cometary dust to study the forces attributed to the sublimation of ice. Methods. We extended the recently introduced synoptic model for ice-free dust particles to ice-containing dust. We introduced an additional source term to the energy balance equation accounting for the heat of sublimation and condensation. We use the direct simulation Monte Carlo approach with the dusty gas model to solve the mass balance equation and the energy balance equation simultaneously. Results. The numerical tests show that the proposed method can be applied for dust particles covering the size range from tens of microns to centimeters with a moderate computational cost. We predict that for an assumed ice volume fraction of 0.05, particles with a radius, r >> 1 mm, at 1.35 AU, may disintegrate into mm-sized fragments due to internal pressure build-up. Particles with r < 1 cm lose their ice content within minutes. Hence, we expect that only particles with r > 1cm may demonstrate sustained sublimation and the resulting outgassing forces.
