Observations of Titan's Surface and Atmosphere from the Descent Imager/Spectral Radiometer (DISR) on the Huygens Probe

L. Soderblom (1) , M. Tomasko (2) , B. Archinal (1) , T. Becker (1) , B. Bézard (3) , M. Bushroe (2) , M. Combes (3) , D. Cook (1) , A. Coustenis (3) , C. de Bergh (3) , L. E. Dafoe (2) , L. Doose (2) , Sylvain Douté (4) , A. Eibl (2) , S. Engel (2) , F. Gliem (5) , B. Grieger (6) , T. Hare (1) , K. Holso (2) , E. Howington-Kraus (1) , E. Karkoschka (2) , H. Keller (6) , R. Kirk (1) , R. Kramm (6) , M. Kuppers (6) , P. Lanagan (2) , E. Lellouch (3) , M. Lemmon (7) , J. Lunine (2) , L. Mcfarlane (2) , J. Moores (2) , M. Prout (2) , B. Rizk (2) , M. Rosiek (1) , P. Rueffer (5) , S. E. Schröder (6) , Bernard Schmitt (4) , C. See (2) , P. Smith (2) , N. Thomas (8) , R. West (9)

1 Astrogeology Science Center [Flagstaff]
2 LPL - Lunar and Planetary Laboratory [Tucson]
3 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
4 LPG - Laboratoire de Planétologie de Grenoble
5 Institut fur Datenverarbeitung
6 MPS - Max Planck Institute for Solar System Research
7 Department of Physics
8 Physikalisches Institut [Bern]
9 JPL - Jet Propulsion Laboratory

DISR characterized atmospheric radiation (350-1600 nm) and returned images and spectra of the surface of Titan. Linear polarization of the aerosol haze extending to the surface is i ˜50% at visible wavelengths. Monomers making up the aerosol particles are modeled at ˜0.1 microns, several 100 monomers making up a haze particle. The extinction optical depth at the surface is ˜4.5 at 531 nm, ˜2 at 939 nm and ˜0.5 at 1500 nm. The near-surface methane mole fraction is ˜5% (relative humidity ˜50%); methane fog or rain at the landing site is currently unlikely. Below ˜8 km the eastward zonal wind dropped to <1m/s and reversed back to the west indicative of a boundary layer. Surface reflectance is ˜0.13 at 531 nm, ˜0.18 at 830 nm, decreasing to ˜0.06 at 1500 nm consistent with dirty water ice. DISR images show brighter, higher terrains with stubby and higher-order drainage systems that border darker, lower-lying plains scoured by flow. Surface images show rounded gravels in a dry river bed. DISR-derived topography for the drainages in the bright terrain show extremely rugged terrain with slopes as high as 30 degrees. This suggests relatively rapid erosion by flows in the river beds resulting in the deeply incised valleys.

L. Soderblom, M. Tomasko, B. Archinal, T. Becker, B. Bézard, et al.. Observations of Titan's Surface and Atmosphere from the Descent Imager/Spectral Radiometer (DISR) on the Huygens Probe. 37th DPS Meeting, 2005, Cambridge, United Kingdom. pp.622. ⟨insu-00356824⟩