Titan's surface and atmosphere observed by the DISR/Huygens instrument
Abstract
The Descent Imager / Spectral Radiometer (DISR) aboard the Huygens probe measured solar radiation in the atmosphere of Titan and took images and spectra of its surface. A summary of the early data analysis is presented. The images taken by DISR show brighter highland regions with channel and river systems draining into relatively flat, dark lowland terrain. The reflectivity of the dark terrain at the landing site reaches a maximum near 830 nm and decreases gradually at longer wavelengths. The infrared portion of the spectrum is consistent with dirty water ice but the nature and composition of the dark material forming the ``dirt'' is unknown. Several haze properties were determined. The haze extends from the highest measured altitude (150 km) down to the surface. Its optical depth is about 2 at 940 nm and decreases with wavelength. The particles are irregular and can be modelled as aggregates of several hundreds of 0.05-μm radius monomers. A methane mixing ratio of 5±1% was inferred near the surface using a downward-looking spectrum at an altitude of 20 m with the DISR lamp turned on.
- Publication:
-
SF2A-2005: Semaine de l'Astrophysique Francaise
- Pub Date:
- December 2005
- Bibcode:
- 2005sf2a.conf..125B