• bitcomet0.59 > coordinated 1996 hst and irtf imaging of neptune and tritonii...
  • coordinated 1996 hst and irtf imaging of neptune and tritonii...

    免费下载 下载该文档 文档格式:PDF   更新时间:2007-12-01   下载次数:0   点击次数:2
    文档基本属性
    文档语言:
    文档格式:pdf
    文档作者:Natale Zappia
    关键词:
    主题:
    备注:
    点击这里显示更多文档属性
    Icarus 149, 435–458 (2001) doi:10.1006/icar.2000.6563, available online at http://www.idealibrary.com on
    Coordinated 1996 HST and IRTF Imaging of Neptune and Triton
    II. Implications of Disk-Integrated Photometry1
    L. A. Sromovsky2 and P. M. Fry
    Space Science and Engineering Center, University of Wisconsin, Madison, Wisconsin 53706 E-mail: larry.sromovsky@ssec.wisc.edu
    K. H. Baines2
    Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109
    and T. E. Dowling
    Comparative Planetology Laboratory, University of Louisville, Louisville, Kentucky 40292 Received July 15, 1999; revised October 17, 2000
    Near-IR groundbased observations coordinated with Wide Field Planetary Camera 2 (WFPC2) HST observations (Sromovsky et al. Icarus 149, 416–434, 459–488) provide new insights into the variations of Neptune and Triton over a variety of time scales. From 1996 WFPC2 imaging we nd that a broad circumpolar nonaxisymmetric dark band dominates Neptune's lightcurve at 0.467 m, while three discrete bright features dominate the lightcurve at longer wavelengths, with amplitudes of 0.5% at 0.467 m and 22% at 0.89 m, but of opposite phases. The 0.89-m modulation in 1994, estimated at 39%, is close to the 50% modulation observed during the 1986 "outburst" documented by Hammel et al. (1992, Icarus 99, 363–367), suggesting that the unusual 1994 cloud morphology might also have been present in 1986. Lightcurve amplitudes in J–K bands, from August 1996 IRTF observations, are comparable to those observed in 1977 (D. P. Cruikshank 1978, Astrophys. J. Lett. 220, 57–59) but signicantly larger than the 1981 amplitudes of M. J. S. Belton et al. (1981, Icarus 45, 263–273). The 1996 disk-integrated albedos of Neptune at H–K wavelengths are 2–7 times smaller than the 1977 values of U. Fink and S. Larson (1979, Astrophys. J. 233, 1021–1040), which can be explained with about 1/2–1/4 of the upper level cloud opacity being present in 1996. A simplied three-layer model of cloud structure applied to CCD wavelengths implies 7% reectivity at 1.3 bars (at λ = 0.55 m,

    下一页

  • 下载地址 (推荐使用迅雷下载地址,速度快,支持断点续传)
  • 免费下载 PDF格式下载
  • 您可能感兴趣的
  • bitcometbitspirit  bitcomet比特彗星  bitcomet软件  bitcomet种子市场  bitcomet官网  bitcomet下载加速办法  bitcomet超级优化设置  bitcomet  bitcomet0.70