The Chemistry and Physics of Titan's Upper Atmosphere Revealed by the Atacama Large Millimeter/submillimeter Array

土星的卫星土卫六的大气由氮、碳等分子和其他元素组成，这些元素存在于像地球这样的岩石行星的早期大气中。我们研究土卫六的大气层是为了更多地了解地球大气层的早期历史。卡西尼号航天器绘制了简单的碳和氮分子图，揭示了随着土卫六季节的变化而变化的许多分子模式。然而，这些只是土卫六大气中的一小部分分子，我们没有覆盖整个土卫六的大气。这是卡西尼号运营的最后一年。与卡西尼号同时使用新的阿塔卡马大毫米/亚毫米阵列(ALMA)射电望远镜天文台，天文学家将利用射电望远镜和航天器完全观察土卫六的大气。他们将绘制泰坦大气中分子类型和数量的第一张三维地图。然后，他们将对结果进行建模，以了解大气中的分子是如何产生、运输和随时间变化的。来自华盛顿特区少数族裔学校的本科生物理学和天文学专业的学生将在NASA戈达德太空飞行中心的首席研究员的投入和支持下进行独立的太阳系研究。土星的卫星土卫六有厚厚的富含氮和碳的大气层，富含复杂的有机分子。它是原始地球天体(包括早期地球)的潜在类似物。NASA卡西尼号航天器上的仪器提供了较小的碳氢化合物和腈的地图，揭示了许多复杂的、随季节变化的分子丰度模式。然而，这些观测只追踪了泰坦分子清单中的一小部分，而且空间和时间覆盖范围都不完整。了解土卫六大气气体的形成和演化是确定其他原始行星大气中存在的分子清单的关键一步。阿塔卡马大毫米/亚毫米阵列(ALMA)是一种革命性的工具，用于探测和即时绘制土卫六气体的日光-半球图。在运行的最后一年，ALMA将与卡西尼号同时使用，以提供泰坦大气层的完整景象。这项研究将为土卫六上的多个分子物种制作第一张瞬时的、空间分辨率的三维分子丰度图，为理解行星大气的基本物理和化学提供新的和严格的测试。对这些地图的解释将有助于生成更详细的化学模型，以洞察分子物质的全球生产、运输和演化，特别是在土卫六研究较少的中高层大气中。同位素丰度比将有助于限制化学途径，并追踪土卫六氢和氮的起源和演化。首席研究员将指导华盛顿特区少数族裔服务机构的本科生物理和天文学学生，他们将在NASA戈达德太空飞行中心进行独立的太阳系研究。

The atmosphere of Saturn's moon Titan is composed of molecules such as nitrogen and carbon and other elements that were present in the early atmospheres of the rocky planets like Earth. We study Titan's atmosphere to learn more about the early history of the Earth's atmosphere. Cassini spacecraft has mapped simple carbon and nitrogen molecules, revealing many patterns of molecules that change with the changing seasons of Titan. These are, however, only a small number of the types of molecules in Titan's atmosphere, and we do not have coverage of the atmosphere across all of Titan. This is Cassini's last year of operation. Using the new Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope observatory at the same time as Cassini, the astronomers will observe Titan's atmosphere completely using both the radio telescopes and the spacecraft. They will make the first 3-dimensional maps of the types and amounts of molecules in Titan's atmosphere. They will then model the results to learn about how the molecules in the atmosphere are produced, transported, and changed with time. Undergraduate physics and astronomy students from minority-serving schools in the Washington DC area will conduct independent Solar System research with the principal investigator's input and backing at NASA's Goddard Space Flight Center.Saturn's moon Titan has a thick nitrogen and carbon-rich atmosphere, abundant in complex organic molecules. It is a potential analogue for primitive terrestrial bodies (including the early Earth). Instruments onboard NASA's Cassini spacecraft have provided maps of the smaller hydrocarbons and nitriles, revealing many complex, seasonally-varying molecular abundance patterns. These observations, however, trace only a small subset of Titan's molecular inventory, and have incomplete spatial and temporal coverage. Understanding the formation and evolution of Titan's atmospheric gases is a key step in determining the molecular inventories present in other primitive planetary atmospheres. The Atacama Large Millimeter/submillimeter Array (ALMA) is a revolutionary tool for the detection and instantaneous daylight-hemisphere mapping of Titan's gases. ALMA will be used concurrently with Cassini during its final year of operation to provide complete views of Titan's atmosphere. This research will produce the first instantaneous, spatially-resolved 3-dimensional molecular abundance maps for multiple molecular species on Titan, allowing new and rigorous tests for understanding the basic physics and chemistry of planetary atmospheres. Interpretation of these maps will help generate more detailed chemical models to provide insight into the global production, transport and evolution of molecular material, particularly in Titan's less well-studied middle and upper atmospheres. Isotope abundance ratios will help constrain chemical pathways and trace the origin and evolution of Titan's hydrogen and nitrogen. The principal investigator will mentor undergraduate physics and astronomy students from minority-serving institutions in the Washington DC area, who will conduct independent Solar System research at NASA's Goddard Space Flight Center.