Properties of Interstellar Dust Grains

该项目的主要目标是在卡西尼尘埃探测器收集的数据集中识别星际起源的颗粒，卡西尼尘埃探测器能够测量撞击颗粒的动态特性和组成。对它们的质谱的分析第一次提供了关于行星形成早期固体物质组成的明确信息，以及关于富碳恒星、红巨星和超新星中星系尘埃的产生速率。目前关于星际尘埃（ISD）组成的知识主要来自天文观测，这是非常有限的。星尘号太空探测器可能已经收集了一些星际颗粒，但到目前为止，检查小组还没有在气凝胶样本中发现这些颗粒。卡西尼号太空探测器上的尘埃仪器提供了一个独特的机会来获取原位ISD数据，因为在卡西尼号进入环绕土星的轨道后不久，ISD的观测条件变得有利。此外，ISD粒子可以在卡西尼号的数据集中可靠地识别出来，因为它们的运动学和组成特性与形成土星环的颗粒以及行星际颗粒不同。

The main goal of the project is to identify grains of interstellar origin in the data set collected by the Cassini dust detector, which is capable to measure the dynamic properties and the composition of the impacting particles. The analysis of their mass spectra provides for the first time unequivocal information about the composition of solid material at the earliest phases of planet formation as well as about the production rates of galactic dust in carbon-rich stars, red giants, and supernovae. The current knowledge of the composition of interstellar dust (ISD) stemming dominantly from astronomical observations is extremely limited. The Stardust spaceprobe may have collected a few interstellar grains, but so far the examination team has not yet identified such grains within the aerogel samples. The dust instrument onboard the Cassini spaceprobe provides an unique opportunity to obtain in-situ ISD data because shortly after Cassini’s entry into its orbit around Saturn, the ISD observation conditions became favourable. Furthermore, ISD particles can be reliably identified in the Cassini data set because their kinematic and compositional properties are distinct from grains forming Saturn’s rings as well as from interplanetary grains.