卡西尼号成像科学：土卫九和土卫八的初步结果。

Cassini Imaging Science: initial results on Phoebe and Iapetus.

作者信息

Porco C C, Baker E, Barbara J, Beurle K, Brahic A, Burns J A, Charnoz S, Cooper N, Dawson D D, Del Genio A D, Denk T, Dones L, Dyudina U, Evans M W, Giese B, Grazier K, Helfenstein P, Ingersoll A P, Jacobson R A, Johnson T V, McEwen A, Murray C D, Neukum G, Owen W M, Perry J, Roatsch T, Spitale J, Squyres S, Thomas P C, Tiscareno M, Turtle E, Vasavada A R, Veverka J, Wagner R, West R

机构信息

Cassini Imaging Central Laboratory for Operations, Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA.

出版信息

Science. 2005 Feb 25;307(5713):1237-42. doi: 10.1126/science.1107981.

DOI:10.1126/science.1107981

PMID:15731440

Abstract

The Cassini Imaging Science Subsystem acquired high-resolution imaging data on the outer Saturnian moon, Phoebe, during Cassini's close flyby on 11 June 2004 and on Iapetus during a flyby on 31 December 2004. Phoebe has a heavily cratered and ancient surface, shows evidence of ice near the surface, has distinct layering of different materials, and has a mean density that is indicative of an ice-rock mixture. Iapetus's dark leading side (Cassini Regio) is ancient, heavily cratered terrain bisected by an equatorial ridge system that reaches 20 kilometers relief. Local albedo variations within and bordering Cassini Regio suggest mass wasting of ballistically deposited material, the origin of which remains unknown.

摘要

卡西尼号成像科学子系统在2004年6月11日卡西尼号近距离飞越土卫九期间，以及在2004年12月31日飞越土卫八期间，获取了土星外层卫星土卫九和土卫八的高分辨率成像数据。土卫九表面布满撞击坑且年代久远，有证据表明其表面附近存在冰，不同物质有明显分层，平均密度表明它是冰岩混合物。土卫八黑暗的正面（卡西尼区）年代久远，布满撞击坑的地形被一个赤道脊系统一分为二，该系统的地形起伏达20公里。卡西尼区内及周边的局部反照率变化表明，弹道沉积物质存在质量流失现象，其来源尚不清楚。