Ralph: A Visible/Infrared Imager for the New Horizons Pluto/Kuiper Belt Mission
Dennis C. Reuter, S. Alan Stern, John Scherrer, Donald E. Jennings, James Baer, John Hanley, Lisa Hardaway, Allen Lunsford, Stuart McMuldroch, Jeffrey Moore, Ca… 展开作者
Dennis C. Reuter, S. Alan Stern, John Scherrer, Donald E. Jennings, James Baer, John Hanley, Lisa Hardaway, Allen Lunsford, Stuart McMuldroch, Jeffrey Moore, Cathy Olkin, Robert Parizek, Harold Reitsma, Derek Sabatke, John Spencer, John Stone, Henry Throop, Jeffrey Van Cleve, Gerald E. Weigle, Leslie A. Young
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18 pages, 15 figures, 4 tables; To appear in a special volume of Space Science Reviews on the New Horizons mission
The New Horizons instrument named Ralph is a visible/near infrared multi-spectral imager and a short wavelength infrared spectral imager. It is one of the core instruments on New Horizons, NASA's first mission to the Pluto/Charon system and the Kuiper Belt. Ralph combines panchromatic and color imaging capabilities with IR imaging spectroscopy. Its primary purpose is to map the surface geology and composition of these objects, but it will also be used for atmospheric studies and to map the surface temperature. It is a compact, low-mass (10.5 kg), power efficient (7.1 W peak), and robust instrument with good sensitivity and excellent imaging characteristics. Other than a door opened once in flight, it has no moving parts. These characteristics and its high degree of redundancy make Ralph ideally suited to this long-duration flyby reconnaissance mission.
Collision rates in the present-day Kuiper Belt and Centaur Regions: Applications to surface activation and modification on Comets, Kuiper Belt Objects, Centaurs, and Pluto-Charon
Time-Resolved Photometry of Kuiper Belt Objects: Rotations, Shapes and Phase Functions
我们提出了一个系统的调查的基础上广泛的光学数据莫纳克亚的海王星外天体的旋转光变曲线。在我们的样本中，13个天体中有4个（相当于31%）（（33128）1998 BU 48，2000 GN 171，（20000）Varuna和1999 KR 16）显示出峰-峰范围> 0.15等的光变曲线。在通过将我们的数据与文献中可靠确定的光变曲线相结合而获得的更大样本中，22个物体中有7个（32%）显示出显著的（> 0.15星等范围）光变曲线。大约23%的采样对象的光变曲线范围> 0.4星等。奇怪的是，这些天体非常大（直径大于250公里，假设旋度为0.04），在没有自转的情况下，由于自压缩，应该接近球形。我们提出，大振幅，短周期的对象是旋转扭曲，低密度碎石桩。从统计学上看，海王星外天体的球形度低于主带小行星，这表明形成时期可能导致了更高的比角动量。除了旋转光变曲线，我们还测量了7个柯伊伯带天体在0到2度相位角范围内的相位变暗。与冥王星不同的是，测量值显示陡峭的斜坡和适度的反对浪潮，表明低散射多孔表面材料的后向散射。
