Search Publications
Evidence for layered methane clouds in Titan’s troposphere
Atreya, Sushil K.; Wang, Chia C.; Signorell, Ruth
Layered methane clouds in Titan's troposphere with an upper methane ice cloud, a lower liquid methane-nitrogen cloud, and a gap in between were suggested from in situ measurements and ground-based observations. Here we report laboratory investigations under conditions that mimic Titan's troposphere providing a detailed picture of the cloud layers.…
A tropical haze band in Titan’s stratosphere
Irwin, P. G. J.; Teanby, N. A.; de Kok, R. +7 more
Inspection of near-infrared images from Cassini's Imaging Science Subsystem and Visual and Infrared Mapping Spectrometer have revealed a new feature in Titan's haze structure: a narrow band of increased scattering by haze south of the equator. The band seems to indicate a region of very limited mixing in the lower stratosphere, which causes haze p…
Atmospheric control of the cooling rate of impact melts and cryolavas on Titan’s surface
Sotin, Christophe; Baines, Kevin H.; Choukroun, Mathieu +4 more
As on Earth, Titan's atmosphere plays a major role in the cooling of heated surfaces. We have assessed the mechanisms by which Titan's atmosphere, dominantly N 2 at a surface pressure of 1.5 × 10 5 Pa, cools a warm or heated surface. These heated areas can be caused by impacts generating melt sheets and (possibly) by endogeni…
Impact-induced N2 production from ammonium sulfate: Implications for the origin and evolution of N2 in Titan’s atmosphere
Fukuzaki, Sho; Sekine, Yasuhito; Genda, Hidenori +3 more
Chemical reactions and volatile supply through hypervelocity impacts may have played a key role for the origin and evolution of both planetary and satellite atmospheres. In this study, we evaluate the role of impact-induced N 2 production from reduced nitrogen-bearing solids proposed to be contained in Titan's crust, ammonium sulfate ((…
Hydrodynamical simulations of viscous overstability in Saturn’s rings
Ogilvie, Gordon I.; Latter, Henrik N.
We perform axisymmetric hydrodynamical simulations that describe the nonlinear outcome of the viscous overstability in dense planetary rings. These simulations are particularly relevant for Cassini observations of fine-scale structure in Saturn's A and B-ring, which take the form of periodic microstructure on the 0.1 km scale, and irregular larger…
Theory of the rotation of Janus and Epimetheus
Noyelles, Benoît
The saturnian coorbital satellites Janus and Epimetheus present a unique dynamical configuration in the Solar System, because of high-amplitude horseshoe orbits, due to a mass ratio of order unity. As a consequence, they swap their orbits every 4 years, while their orbital periods is about 0.695 days. Recently, Tiscareno et al. (Tiscareno, M.S., T…
Titan’s atomic hydrogen corona
Wurz, P.; Lammer, H.; Rauer, H. +5 more
Based on measurements performed by the Hydrogen Deuterium Absorption Cell (HDAC) aboard the Cassini orbiter, Titan's atomic hydrogen exosphere is investigated. Data obtained during the T9 encounter are used to infer the distribution of atomic hydrogen throughout Titan's exosphere, as well as the exospheric temperature. The measurements performed d…
Characteristics of Saturn’s FUV airglow from limb-viewing spectra obtained with Cassini-UVIS
Gérard, Jean-Claude; Stewart, Ian; Gustin, Jacques +1 more
This study reports the analysis of far ultraviolet (FUV) limb spectra of the airglow of Saturn in the 1150-1850 Å spectral window, obtained with the Ultraviolet Imaging Spectrograph (UVIS) onboard Cassini, spanning altitudes from -1200 to 4000 km. The FUV limb emission consists of three main contributions: (1) H Ly-α peaking at 1100 km with a brig…
A spherical Monte-Carlo model of aerosols: Validation and first applications to Mars and Titan
Langevin, Yves; Vincendon, Mathieu
The atmospheres of Mars and Titan are loaded with aerosols that impact remote sensing observations of their surface. Here we present the algorithm and the first applications of a radiative transfer model in spherical geometry designed for planetary data analysis. We first describe a fast Monte-Carlo code that takes advantage of symmetries and geom…
Chemical reactions in the Titan’s troposphere during lightning
Kovács, Tamás; Turányi, Tamás
In the lower troposphere of the Titan the temperature is about 90 K, therefore the chemical production of compounds in the CH 4/N 2 atmosphere is extremely slow. However, atmospheric electricity could provide conditions at which chemical reactions are fast. This paper is based on the assumption that there are lightning discha…