Silica has emerged as a crucial component within inner comet comas. This work investigates silica dust aggregates and their interactions within cometary comas. We study the probability that aggregates in the size range 1-100 μm collide with each other in the coma and analyze the outcomes of such collisions by using the “Collision of Porous Aggregates” (CPA) Software, which incorporates mass, size, and porosity evolution of the dust population. Beginning with assumed initial distributions and physical properties for silica aggregates at the comet nucleus, we compute their collisional evolution from when they depart the nucleus until they traverse the coma. Using data of dust particles observed in the coma of comet 67P/Churyumov-Gerasimenko, we demonstrate that dust-dust collisions in cometary comas cannot be neglected. Our analysis yields final distributions in terms of mass, size, and porosity. To validate our findings, we compare them with in-situ measurements of 67P/Churyumov-Gerasimenko collected by the COSIMA (COmetary Secondary Ion Mass Analyser) instrument of the Rosetta mission. Our investigation reveals a notable agreement between our derived size distributions and the data acquired by COSIMA within the same size range. This study may be applied to any comet that presents a similar dust production as it approaches the Sun. The insights of this work may contribute to estimating other dust properties such as strength, absorption, reflectivity, and thermal conductivity and highlight the importance of considering dust-dust collisions when studying cometary comas and their evolution.

中文翻译：

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彗星彗发中的尘埃碰撞：67P/Churyumov-Gerasimenko 彗星的应用

二氧化硅已成为彗星内部彗发的重要组成部分。这项工作研究了二氧化硅尘埃聚集体及其在彗星彗发内的相互作用。我们研究了尺寸范围为 1-100 μm 的聚集体在彗发中相互碰撞的概率，并使用“多孔聚集体碰撞”(CPA) 软件（该软件结合了质量、尺寸和孔隙率）分析了此类碰撞的结果尘埃种群的演变。从彗核处二氧化硅聚集体的假设初始分布和物理性质开始，我们计算了它们从离开彗核直到穿过彗发的碰撞演化。利用在 67P/Churyumov-Gerasimenko 彗星彗发中观测到的尘埃粒子数据，我们证明彗星彗发中的尘埃碰撞不容忽视。我们的分析得出了质量、尺寸和孔隙率的最终分布。为了验证我们的发现，我们将它们与罗塞塔任务的 COSIMA（COmetary 二次离子质量分析仪）仪器收集的 67P/Churyumov-Gerasimenko 现场测量结果进行了比较。我们的调查显示，我们得出的尺寸分布与 COSIMA 在相同尺寸范围内获取的数据之间存在显着的一致性。这项研究可适用于任何在接近太阳时产生类似尘埃的彗星。这项工作的见解可能有助于估计其他尘埃特性，如强度、吸收性、反射率和导热性，并强调在研究彗星彗发及其演化时考虑尘埃碰撞的重要性。