Data acquired at Ceres by the visible channel of the Visible and InfraRed mapping spectrometer (VIR) on board the NASA Dawn spacecraft are affected by the temperatures of both the visible (VIS) and the infrared (IR) sensors, which are, respectively, a charged coupled device and a HgCdTe array. The variations of the visible channel temperatures measured during the sessions of acquisitions are correlated with the variations in the spectral slope and shape for all the mission phases. The IR channel temperature is more stable during the acquisitions; nonetheless, it is characterized by a bimodal distribution whether the cryocooler (and, therefore, the IR channel) is used or not during the visible channel operations. When the infrared channel temperature is high (175 K, i.e., not in use and with the cryocooler off), an additional negative slope and a distortion are observed in the spectra of the visible channel. We developed an empirical correction based on a reference spectrum for the whole dataset; it is designed to correct the two issues related to the sensor temperatures that we have identified. The reference spectrum is calculated to be representative of the global Ceres' surface. It is also made of the data acquired when the visible and infrared channel temperatures are equal to the ones measured during an observation of the Arcturus star by VIR, which is consistent with several ground-based observations. The developed correction allows reliable analysis and mapping to be performed by minimizing the artifacts induced by fluctuations of the VIS temperature. Thanks to this correction, a direct comparison between different mission phases during which the VIR experienced different visible and infrared channel temperatures is now possible.

中文翻译：

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修正黎明号任务的 VIR 可见数据集

美国宇航局黎明号航天器上的可见光和红外测绘光谱仪 (VIR) 的可见光通道在谷神星获取的数据受到可见光 (VIS) 和红外 (IR) 传感器温度的影响，它们分别是电荷耦合器件和 HgCdTe 阵列。在采集会话期间测量的可见通道温度的变化与所有任务阶段的光谱斜率和形状的变化相关。红外通道温度在采集过程中更加稳定；尽管如此，在可见光通道操作期间，无论是否使用低温冷却器（以及因此，IR 通道），其特征在于双峰分布。当红外通道温度较高时（175 K，即未使用且冷冻机关闭），在可见光通道的光谱中观察到额外的负斜率和失真。我们根据整个数据集的参考光谱开发了经验校正；它旨在纠正与我们已确定的传感器温度相关的两个问题。计算出的参考光谱代表了全球谷神星的表面。它还由可见光和红外通道温度与通过 VIR 观测大角星时测得的温度相等时获得的数据组成，这与一些地面观测结果一致。开发的校正允许通过最小化由 VIS 温度波动引起的伪影来执行可靠的分析和映射。由于这次更正，