Experimental Chondrule Formation I - Lightning Discharge Experiments under Microgravity Conditions at the International Space Station

球粒形成实验I——国际空间站微重力条件下的闪电放电实验

• 批准号: 418578734
• 负责人: Professor Dr. Frank Erich Brenker
• 金额: --
• 依托单位: Fachrichtung Mineralogie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/418578734?language=en
• 关键词: Experimental; Chondrule; Formation; Lightning; Discharge

With this project we intend to study the formation mechanism of chondrules, one of the most important and most frequent solids formed within the first million years of the Solar System. Although known for almost hundred years the formation mechanism is still a matter of intense scientific debate. Just recently the discussion about the formation mechanism of chondrules get several new impulses and re-activated a few of the most favorable formation mechanism like nebular lightning discharges (e.g. Johansen and Okuzumi, 2018), nebular shock waves (e.g. Desch et al., 2012; Fedkin et al., 2012) and asteroidal collision (e.g. Sanders and Scott, 2012). In addition several new aspects of the chondrule formation process itself were published (Palme et al., 2015; Friend, 2017). Taking all this into account the lack of experimental chondrule formation at conditions relevant to the solar nebula, e.g under microgravity, is obvious.The new experimental approach presented here will be performed under microgravity conditions aboard the International Space Station during Alexander Gerst´s current space mission. The sample container will returned to Earth in December 2018 for detailed analytical laboratory studies. The experiment was accepted as one of only three experiments within the framework of the “Ueberflieger”- competition. The proposal presented here will cover the detailed analytical study of the sample material after returned to Earth and the evaluation of the full digital video coverage of the experiment.The main goals of the project are:1) Is lightning are reasonable process to produce chondrule like objects under microgravity conditions?2) Do melting of dust aggregates enhance particle growth?3) What are the structural details of the chondrule like objects formed and can they be related to specific known chondrule types expected to form at high cooling rates, like cryptocrystalline, radial olivine or barred olivine chondrules.4) What are the geochemical consequences on chondrules formed by lightning discharges?5) What is the degree of crystallinity obtained?6) Do we see phase separation and/or the formation of other phases like pyroxene, commonly found in chondrules?

通过这个项目，我们打算研究软骨的形成机制，这是在太阳系的头百万年内形成的最重要，最频繁的固体之一。尽管近百年来，构成机制仍然是激烈的科学辩论问题。 Just recently the discussion about the formation mechanism of chondrules get several new impulses and re-activated a few of the most favorable formation mechanism like nebular lightning discharges (e.g. Johansen and Okuzumi, 2018), nebular shock waves (e.g. Desch et al., 2012; Fedkin et al., 2012) and asteroidal collision (e.g. Sanders and Scott, 2012).此外，发表了软骨形成过程的几个新方面（Palme等，2015； Friend，2017）。考虑到所有这一切在与太阳星云相关的条件下缺乏实验性软骨形成，例如在微重力下，很明显。此处介绍的新实验方法将在亚历山大·格斯特（Alexander Gerst）当前空间任务期间的国际空间站下进行。样品容器将于2018年12月返回地球进行详细的分析实验室研究。该实验被认为是“ Ueberflieger”竞争框架内仅有的三个实验之一。此处提出的建议将涵盖详细条件。返回地球后对样品材料的分析研究以及对实验的完整数字视频覆盖的评估。项目的主要目标是：1）闪电是在微重力条件下产生像对象的合理过程吗？2）灰尘聚集物的融化？加密晶体，径向橄榄石或禁止的橄榄石软骨。4）通过闪电放电形成的软骨形成的地球化学后果是什么？5）5）获得的结晶性程度是什么？6）我们是否看到相位分离和//或其他阶段的形成，例如诸如Pyroxene，通常在Chemondrules中？