Infrared Wavelength Observations of Comets

一个研究一颗特别有趣的彗星2060凯龙星的独特机会即将到来。凯龙彗星现在接近近日点（1996年2月），将是51年来最亮的时候。同时，预定于1995年9月发射的欧洲空间局红外空间观测站将在其18个月的任务期间对凯龙星进行观测。将对凯龙星和另外两颗彗星进行地基和天基协调研究。频繁的地面和高灵敏度的天基红外波长观测相结合，将获得关于这三颗彗星的广泛信息。国际标准化组织对这些彗星的观测时间已经分配给了这个小组。以下项目描述了研究的主要目标。1. 表征凯龙星在电磁波谱的红外波长区域的可变性。地面观测对支持国际标准化组织的有用性主要是因为国际标准化组织卫星观测凯龙星（和大多数其他目标）的时间不够长，无法描述它们的红外变异性，国际标准化组织卫星的观测时间将主要用于获得使用地面望远镜无法获得的观测结果。2. 凯龙星核的理论热模型将被测试。一个)。在冲日前后对凯龙星核的热红外观测可以揭示哪一种几何形状呈现较冷的晨光终结者，从而通过探测温度变化来区分顺行和逆行旋转。b。)近日点前后的频繁观测可以用来诊断一些核特征，包括极的方向。3. 次要目标的观测。类似的，但必然不那么详细的对彗星d’arrest和Kopff的研究，将进行。这两颗彗星也将被国际标准化组织观测，并将在1995-1996年进行观测。

9522568 Campins A unique opportunity to study a particularly interesting comet, 2060 Chiron, is at hand. Comet Chiron is now near perihelion (February 1996) and will be at its brightest in 51 years. Simultaneously, the European Space Agency's Infrared Space Observatory (ISO), which is scheduled for launch in September 1995, will be making observations of Chiron during its 18-month mission. A coordinated ground-based and space-based study of Chiron, and two other comets, will be carried out. The combination of frequent ground-based, and high sensitivity space-based, infrared wavelength observations, will yield extensive information about these three comets. The ISO observing time for these comets has already been assigned to the team. The following items describe the main goals of the research. 1. Characterization of Chiron's variability in the infrared wavelength region of the electromagnetic spectrum. The usefulness of ground-based observations in support of ISO arises mostly because the time assigned on the ISO satellite to observe Chiron (and most other targets) is not sufficiently long to characterize their infrared variability, and observing time by the ISO satellite will be spent mainly obtaining observations which are not possible using ground-based telescopes. 2. Theoretical thermal models of Chiron's nucleus will be tested. a.) Thermal-infrared observations of Chiron's nucleus before and after opposition can reveal which of those geometries presents the cooler morning terminator, and hence distinguish between prograde and retrograde rotation by detecting temperature changes. b.) Frequent observations before and after perihelion can be used as a diagnostic of a number of nuclear characteristics, including the pole orientation. 3. Observations of secondary targets. Similar, but necessarily less detailed studies of Comets d'Arrest and Kopff, will be carried out. These two comets will also be observed by ISO, and will b e well placed for observations in 1995-1996.