The geology of Hotei Regio, Titan: Correlation of Cassini VIMS and RADAR
Section snippets
Introduction and background
Hotei Regio (IAU formal name for a ∼700-km-wide region centered at 78°W 26°S) has been flagged as an enigmatic region on Titan in various analyses of Cassini visible-light, short-wavelength-infrared, and radar observations. Hotei Arcus (also an IAU formal name) is a bright arc that forms the southern margin of Hotei Regio; we further clarify this distinction in Section 2. A consensus is emerging that Hotei Regio is a geologically young cryovolcanic region. Cryovolcanism is a term used to
VIMS observations and photometric analysis
The VIMS spectral images described here were acquired on 11/19/2008 during Cassini’s T47 flyby of Titan. Five cubes (CM_1605796665-8513) were acquired of Hotei Regio with resolutions increasing from 18.5 to 12.5 km/pixel. Fig. 1 shows a color mosaic of these data along with individual spectral images for each of eight methane windows taken from the highest-resolution cube (that fortuitously also covers central Hotei Regio). These VIMS cubes were acquired close to the terminator. For the area of
Mapping: correlations between VIMS and SAR
In general, Titan’s surface features as seen in VIMS and SAR images are only weakly correlated (Soderblom et al., 2007b); VIMS senses the composition of the upper few tens of microns of the surface, while SAR is sensitive to surface roughness and the scattering properties of the upper meter or so of the surface. The notable exceptions to this weak correlation are vast belts of longitudinal dunes (Lorenz et al., 2006, Radebaugh et al., 2008) whose patterns are strongly correlated in VIMS and SAR
Discussion regional structures and features – speculations on origin and age
The arcuate and linear structures extend far beyond the region of joint SAR–VIMS coverage shown in Fig. 2, Fig. 3. The larger VIMS mosaic of Fig. 1 was spatially filtered (shown in Fig. 4) to enhance structural details and further suppress regional albedo variations and residual photometric errors. The structural arcs described earlier that lie along the outer southern margin of Hotei Regio are quite evident as are the linear radial segments, in particular one that truncates the western end of
Acknowledgments
We are grateful to Ralph Lorenz and Jani Radebaugh for thoughtful and constructive reviews. This research was carried out under funding from the Cassini Flight Project managed by the Jet Propulsion Laboratory, Caltech for NASA.
References (52)
- et al.
Global-scale surface spectral variations on Titan seen from Cassini/VIMS
Icarus
(2007) - et al.
Search for volatiles on icy satellites I-Europa
Icarus
(1988) Kinematic analysis of radial structures around Irnini Mons, Venus
J. Struct. Geol.
(2006)- et al.
The cooling rate of a liquid shell in Titan’s interior
Icarus
(1996) - et al.
Improved near-infrared methane band models and k-distribution parameters from 2000 to 9500 cm−1 and implications for interpretation of outer planet spectra
Icarus
(2006) - et al.
Rheological properties of ammonia–water liquids and crystal–liquid slurries – Planetological applications
Icarus
(1991) - et al.
Formation of methane in comet impacts: Implications for Earth, Mars, and Titan
Icarus
(2004) - et al.
Liquids and solids on the surface of Titan, results of a new photochemical model
Planet. Space Sci.
(1994) - et al.
Clathrate and ammonia hydrates at high pressure: Application to the origin of methane on Titan
Icarus
(1987) - et al.
Physical properties of the organic aerosols and clouds on Titan
Planet. Space Sci.
(2001)
Thermal convection in ice-I shells of Titan and Enceladus
Icarus
Resurfacing of Titan by ammonia–water cryomagma
Icarus
Titan’s orbit provides evidence for a subsurface NH3–water ocean
Icarus
The identification of liquid ethane in Titan’s Ontario Lacus
Nature
The pattern of circumferential and radial eruptive fissures on the volcanoes of Fernandina and Isabela islands, Galapagos
Bull. Volcanol.
Modelling of possible mud volcanism on Titan
Icarus
Complex refractive indices of tholins produced from various initial gas mixtures and formation pressures, implications for Titan, the early Earth, and the outer Solar System bodies
Bull. Am. Astron. Soc.
Cited by (0)
- 1
Deceased.