Occultations by Pluto, Triton and Large Trans-Neptunian Objects

太阳系的天体不时地从明亮的恒星前面经过，将星光切断。被切割的光的数量加上这些通道的时间，告诉我们物体的大小，形状，是否有大气层，以及大气层可能有多厚。这些事件被称为掩星。该项目将观测外海王星天体冥王星、海卫一、Makemake、Quaoar和Salacia对恒星的掩星。自1988年以来，冥王星的大气层一直被掩星所追踪。在此期间，它的大气层变得更厚了。随着冥王星在其轨道上离太阳越来越远，其温度也越来越低，预计它会变得越来越薄。在接下来的三年里，将观测到两次冥王星的掩星，以记录冥王星大气厚度的变化。这些变化将用我们已经掌握的数据来描述冥王星的大气变化。其他被明亮的冰覆盖的大型TNOs也可能像冥王星一样有不断变化的大气层。对上面列出的每一个其他天体都计划观测一个掩星。许多业余天文学家和学生将接受培训，成为掩星观测的一部分。海王星外天体（TNOs）对相当明亮的恒星的掩星提供了一个了解它们的大小、形状和密度，以及任何稀薄大气层的存在和细节的机会。该项目将观测冥王星、海卫一、Makemake、Quaoar和Salacia对恒星的掩星，从而获得对这些天体建立精确大气模型至关重要的数据。自1988年发现冥王星以来，人们一直通过掩星对其大气层进行监测。它的体积大约每十年翻一番，尽管冥王星本身在其轨道上离太阳更远。新视野号宇宙飞船拍摄的冥王星表面图像显示，冥王星大气的来源是巨大的冰库。随着冥王星远离太阳，这些储存库的温度也在逐渐升高，这表明冥王星的地下储存着热量。然而，模型预测冥王星的霜冻温度将很快开始下降。在接下来的三年里，将观测到两次冥王星的掩星，以监测冥王星大气量的变化。其他被明亮的冰覆盖的大型TNOs可能像冥王星一样有不断变化的大气层。对上面列出的每一个其他天体都计划观测一个掩星。计划中的观测将对非常稀薄的大气敏感，并将改进所有物体的大小和形状估计。许多业余天文学家和学生研究人员将接受培训，以支持掩星观测。

Solar System objects pass in front of bright stars from time to time, cutting out the starlight. The amount of light that is cut coupled with the amount of time during these passages tells us about the size, shape, whether the object has an atmosphere, and how thick the atmosphere might be. These events are called occultations. This project will observe occultations of stars by the Trans-Neptunian Objects Pluto, Triton, Makemake, Quaoar, and Salacia. Since 1988, Pluto's atmosphere has been tracked by occultations. Its atmosphere has gotten thicker during this time. It is now expected to get thinner as Pluto moves farther away from the Sun in its orbit, and its temperature gets cooler. Two occultations by Pluto will be observed over the next three years to record changes in the thickness of Pluto's atmosphere. These changes will be modeled with data that we already have to describe how Pluto's atmosphere changes. The other large TNOs, covered with bright ice, could also have changing atmospheres like Pluto. Observations of one occultation are planned for each of the other objects listed above. Many amateur astronomers and students will be trained to be part of the occultation observations.Occultations of reasonably bright stars by Trans-Neptunian Objects (TNOs) provide an opportunity to learn their sizes, shapes and densities, and presence and details of any thin atmospheres. This project will observe occultations of stars by the TNOs Pluto, Triton, Makemake, Quaoar, and Salacia, resulting in data that are crucial to building accurate atmospheric models for these objects. Pluto's atmosphere has been monitored by occultations since its discovery in 1988. It has been doubling in size roughly every ten years, despite the fact that Pluto itself has move farther from the Sun in its orbit. Images of Pluto's surface from the New Horizons spacecraft show large ice reservoirs that are the source of Pluto's atmosphere. These reservoirs have been getting slightly warmer as Pluto has moved away from the Sun, suggesting that Pluto's subsurface stores heat. Models predict, however, that Pluto's frost temperatures will soon start to fall. Two occultations by Pluto will be observed over the next three years to monitor changes in the amount of Pluto's atmosphere. Other large TNOs, covered with bright ice, potentially have changing atmospheres like Pluto. Observations of one occultation are planned for each of the other objects listed above. The planned observations will be sensitive to very thin atmospheres and will refine the size and shape estimates for all objects. Many amateur astronomers and student researchers will be trained and added to support the occultation observations.