Ground-based near infrared spectroscopy of Jupiter's ring and moons

被引:9
|
作者
Wong, Michael H.
de Pater, Irake
Showalter, Mark R.
Roe, Henry G.
Macintosh, Bruce
Verbanac, Giuli
机构
[1] Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA
[2] SETI Inst, Mountain View, CA 94043 USA
[3] CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA
[4] Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA
[5] Univ Zagreb, Fac Sci, Zagreb 1000, Croatia
基金
美国国家航空航天局;
关键词
planetary rings; Jupiter; infrared observations; spectroscopy; satellites;
D O I
10.1016/j.icarus.2006.07.007
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
The backscattered reflectivity of Jupiter's ring has been previously measured over distinct visible and near infrared wavelength bands by a number of ground-based and spaceborne instruments. We present spectra of Jupiter's main ring from 2.21-2.46 mu m taken with the NIRSPEC spectrometer at the W.M. Keck observatory. At these wavelengths, scattered light from Jupiter is minimal due to the strong absorption of methane in the planet's atmosphere. We find an overall flat spectral slope over this wavelength interval, except for a possible red slope shortward of 2.25 mu m. We extended the spectral coverage of the ring to shorter wavelengths by adding a narrow-band image at 1.64 mu m, and show results from 2.27-mu m images over phase angles of 1.2 degrees-11.0 degrees. Our images at 1.64 and 2.27 mu m reveal that the halo contribution is stronger at the shorter wavelength, possibly due to the redder spectrum of the ring parent bodies as compared with the halo dust component. We find no variation in main ring reflectivity over the 1.2 degrees-11.0 degrees phase angle range at 2.27 mu m. We use adaptive optics imaging at the longer wavelength L ' band (3.4-4.1 mu m) to determine a 2-sigma upper limit of 22 m of vertically-integrated I/F. Our observing campaign also produced an L ' image of Callisto, showing a darker leading hemisphere, and a spectrum of Amalthea over the 2.2-2.5 and 2.85-3.03 mu m ranges, showing deep 3-mu m absorption. (c) 2006 Elsevier Inc. All rights reserved.
引用
收藏
页码:403 / 415
页数:13
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