Mars' ultraviolet dayglow has been used to study its upper atmosphere for over four decades. Identifying variations in emission features has provided information on composition, density, and temperature. The Emirates Mars Ultraviolet Spectrometer onboard the Emirates Mars Mission observes Mars' dayglow at Far and Extreme UV wavelengths. Variations in disk emission features are studied, with a focus on O I 130.4, CO Fourth Positive Group and C I 156.1 nm. All show variations with local time (LT) and emission angle as expected. Dawn-dusk asymmetry observed is attributed to LT differences in advection. Variations in the brightness of several dayglow features, including 130.4 nm, with irregular shapes are noted in around 25% of the disk images. These display some LT and hemispheric asymmetry in their occurrence rates. Examination of their spatial structure, occurrence, and spectra suggests these are associated with variations in composition and photoelectron flux.

中文翻译：

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EMM-EMUS观测到的远紫外火星日辉时空结构

四十多年来，火星的紫外线日光一直被用来研究其高层大气。识别排放特征的变化提供了有关成分、密度和温度的信息。阿联酋火星任务上的阿联酋火星紫外光谱仪在远紫外和极紫外波长观察火星的日光。研究了磁盘发射特征的变化，重点是 OI 130.4、CO 第四正组和 CI 156.1 nm。正如预期的那样，所有显示都随着本地时间 (LT) 和发射角的变化而变化。观察到的黎明-黄昏不对称归因于平流的 LT 差异。在大约 25% 的圆盘图像中发现了几个不规则形状的日光特征的亮度变化，包括 130.4 nm。这些在其发生率上显示出一些 LT 和半球不对称性。