This brief review will discuss the current knowledge on the origin and evolution of the nitrogen atmospheres of the icy bodies in the solar system, particularly of Titan, Triton and Pluto. An important tool to analyse and understand the origin and evolution of these atmospheres can be found in the different isotopic signatures of their atmospheric constituents. The 14N/15N ratio of the N2-dominated atmospheres of these bodies serve as a footprint of the building blocks from which Titan, Triton and Pluto originated and of the diverse fractionation processes that shaped these atmospheres over their entire evolution. Together with other measured isotopic and elemental ratios such as 12C/13C or 36Ar/N2 these atmospheres can give important insights into the history of the icy bodies in the solar system, the diverse processes that affect their N2-dominated atmospheres, and the therewith connected solar activity evolution. Titan’s gaseous envelope most likely originated from ammonia ices with possible contributions from refractory organics. Its isotopic signatures can yet be seen in the – compared to Earth – comparatively heavy 14N/15N ratio of 167.7, even though this value slightly evolved over its history due to atmospheric escape and photodissociation of N2. The origin and evolution of Pluto’s and Triton’s tenuous nitrogen atmospheres remain unclear, even though it might be likely that their atmospheres originated from the protosolar nebula or from comets. An in-situ space mission to Triton such as the recently proposed Trident mission, and/or to the ice giants would be a crucial cornerstone for a better understanding of the origin and evolution of the icy bodies in the outer solar system and their atmospheres in general. Due to the importance of the isotopic measurements for understanding the origin and evolution of the icy bodies in the solar system, this review will also give a brief discussion on the diverse isotope measurement techniques with a focus on nitrogen.

中文翻译：

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太阳系冰天体的氮气氛

这篇简短的评论将讨论目前关于太阳系冰天体，特别是泰坦、海卫一和冥王星的冰天体氮大气起源和演化的知识。分析和了解这些大气的起源和演化的重要工具可以在其大气成分的不同同位素特征中找到。这些天体以 N2 为主的大气的 14N/15N 比率是泰坦、海卫一和冥王星起源的基石以及在整个演化过程中塑造这些大气的各种分馏过程的足迹。与其他测量的同位素和元素比率（例如 12C/13C 或 36Ar/N2）一起，这些大气可以提供对太阳系中冰体历史的重要见解，影响其以 N2 为主的大气的各种过程，以及与之相关的太阳活动演变。泰坦的气态包层很可能来自氨冰，可能来自难熔有机物。与地球相比，它的同位素特征仍然可以在 167.7 的相对较重的 14N/15N 比率中看到，尽管由于大气逃逸和 N2 的光解作用，该值在其历史上略有变化。冥王星和海卫一稀薄的氮大气的起源和演化仍不清楚，尽管它们的大气很可能来自原太阳星云或彗星。对海卫一的原位太空任务，例如最近提出的三叉戟任务，和/或冰巨星将是更好地了解太阳系外冰体及其大气的起源和演化的重要基石。由于同位素测量对于理解太阳系冰体起源和演化的重要性，本综述还将简要讨论各种同位素测量技术，重点是氮。