Astronomy 340 Fall 2007. 13 November 2007 Class # 21. Review/Announcements. HW #4 due now HW #5 handed out on Thursday, due Nov 29 Last Time Moons of Jupiter Io Europa. Titan. Discovered in 1655 by Huygens 2 nd largest moon R = 2575 km Density = 1.9 gm cm -3 Orbital properties
13 November 2007
Note variation in color variation in surface features
Bright spot is of particular interest CO2 ice?
Old river beds?
The surface of Saturn's largest satellite—Titan—is largely obscured by an optically thick atmospheric haze, and so its nature has been the subject of considerable speculation and discussion1. The Huygens probe entered Titan's atmosphere on 14 January 2005 and descended to the surface using a parachute system2. Here we report measurements made just above and on the surface of Titan by the Huygens Surface Science Package3, 4. Acoustic sounding over the last 90 m above the surface reveals a relatively smooth, but not completely flat, surface surrounding the landing site. Penetrometry and accelerometry measurements during the probe impact event reveal that the surface was neither hard (like solid ice) nor very compressible (like a blanket of fluffy aerosol); rather, the Huygens probe landed on a relatively soft solid surface whose properties are analogous to wet clay, lightly packed snow and wet or dry sand. The probe settled gradually by a few millimetres after landing.
Zarnecki et al. 2005 Nature 438 792
Study configuration of the rings and dynamic processes responsible for ring structure
Map the composition and size distribution of ring material
Investigate the interrelation of Saturn’s rings and moons, including imbedded moons
Determine the distribution of dust and meteoroid distribution in the vicinity of the rings
Study the interactions between the rings and Saturn’s magnetosphere, ionosphere, and atmosphere
Poulet et al 2003 Astronomy & Astrophysics 412 305
Red slope arises from complex
Variation in grain size included
in model 90% water ice overall
Inner particles overtake outer particles gravitational interaction
Let’s look at some pictures and see what there is to see….