Using data from the Infrared Array Camera on the Spitzer Space Telescope, we present photometric observations of a sample of 100 trans-Neptunian objects (TNOs) beyond 2.2 μm. These observations, collected with two broadband filters centered at 3.6 and 4.5 μm, were done in order to study the surface composition of TNOs, which are too faint to obtain spectroscopic measurements. With this aim, we have developed a method for the identification of different materials that are found on the surfaces of TNOs. In our sample, we detected objects with colors that are consistent with the presence of small amounts of water, and we were able to distinguish between surfaces that are predominantly composed of complex organics and amorphous silicates. We found that 86% of our sample have characteristics that are consistent with a certain amount of water ice, and the most common composition (73% of the objects) is a mixture of water ice, amorphous silicates, and complex organics. Twenty-three percent of our sample may include other ices, such as carbon monoxide, carbon dioxide, methane, or methanol. Additionally, only small objects seem to have surfaces dominated by silicates. This method is a unique tool for the identification of complex organics and to obtain the surface composition of extremely faint objects. Furthermore, this method will be beneficial when using the James Webb Space Telescope for differentiating groups within the trans-Neptunian population.

使用来自斯皮策太空望远镜红外阵列相机的数据，我们展示了超过 2.2 μm的 100 个跨海王星天体 (TNO) 样本的光度观测结果。这些观察结果是用两个以 3.6 和 4.5 μ为中心的宽带滤波器收集的m 是为了研究 TNO 的表面组成，它们太微弱而无法获得光谱测量。为此，我们开发了一种方法来识别在 TNO 表面发现的不同材料。在我们的样本中，我们检测到的物体颜色与少量水的存在一致，我们能够区分主要由复杂有机物和无定形硅酸盐组成的表面。我们发现，86%的样品具有与一定量水冰一致的特征，最常见的成分（73%的物体）是水冰、无定形硅酸盐和复杂有机物的混合物。我们样本的 23% 可能包括其他冰，例如一氧化碳、二氧化碳、甲烷或甲醇。此外，只有小物体的表面似乎以硅酸盐为主。这种方法是识别复杂有机物和获取极微弱物体表面成分的独特工具。此外，当使用詹姆斯韦伯太空望远镜来区分跨海王星种群中的群体时，这种方法将是有益的。