Search Publications
Negative ion densities in the ionosphere of Titan-Cassini RPWS/LP results
Wahlund, J. -E.; Edberg, N. J. T.; Ågren, K. +3 more
The Cassini spacecraft Radio and Plasma Wave Science (RPWS) Langmuir Probe (LP) provides in-situ measurements of Titan's ionosphere. We present here data from 47 deep flybys in the time period October 2004-July 2012 of charge densities of positive and negative ions as well as electrons. These densities have been mapped with respect to altitude and…
Auroral counterpart of magnetic field dipolarizations in Saturn's tail
Dougherty, Michele K.; Cowley, Stanley W. H.; Bunce, Emma J. +6 more
Following magnetic reconnection in a planetary magnetotail, newly closed field lines can be rapidly accelerated back towards the planet, becoming "dipolarized" in the process. At Saturn, dipolarizations are initially identified in magnetometer data by looking for a southward turning of the magnetic field, indicating the transition from a radially …
Composition of Titan's upper atmosphere from Cassini UVIS EUV stellar occultations
Zhang, X.; Shemansky, D. E.; Yung, Y. L. +1 more
Identifying seasonal and spatial variability in Titan's atmospheric structure is a key factor in improving theoretical models of atmospheric loss and understanding the physical processes that control the loss rate. In this work, the extreme ultraviolet (EUV) stellar occultation lightcurves from the Cassini Ultraviolet Imaging Spectrograph (UVIS) e…
Morphotectonic features on Titan and their possible origin
Coustenis, Athena; Solomonidou, Anezina; Bampasidis, Georgios +5 more
Spectro-imaging and radar measurements by the Cassini-Huygens mission suggest that some of the Saturnian satellites may be geologically active and could support tectonic processes. In particular Titan, Saturn's largest moon, possesses a complex and dynamic geology as witnessed by its varied surface morphology resulting from aeolian, fluvial, and p…
Modeling the seasonal variability of the plasma environment in Saturn's magnetosphere between main rings and Mimas
Johnson, R. E.; Elrod, M. K.; Tseng, W. -L.
The detection of O2+ and O+ ions over Saturn's main rings by the Cassini INMS and CAPS instruments at Saturn orbit insertion (SOI) in 2004 confirmed the existence of the ring atmosphere and ionosphere. The source mechanism was suggested to be primarily photolytic decomposition of water ice producing neutral O2…
Saturn's ULF wave foreshock boundary: Cassini observations
Dougherty, M. K.; Mazelle, C.; Bertucci, C. +2 more
Even though the solar wind is highly supersonic, intense ultra-low frequency (ULF) wave activity has been detected in regions just upstream of the bow shocks of magnetized planets. This feature was first observed ahead of the Earth's bow shock, and the corresponding region was called the ULF wave foreshock, which is embedded within the planet's fo…
Timescale for oceans in the past of Titan
McKay, Christopher P.; Larsson, Richard
We estimate the past extent of liquid on the surface of Titan as a function of time assuming the current rate of destruction of methane and no sources or subsurface sinks. As methane increases for increasing past time the polar lakes expand equatorward. We use a spherical harmonics model for the surface topography to compute the fraction of the su…
Recent improvements of the Saturnian satellites atlases: Mimas, Enceladus, and Dione
Matz, K. -D.; Roatsch, Th.; Wählisch, M. +3 more
The Cassini Imaging Science Subsystem (ISS) acquired many high-resolution images (<1 km/pixel) of the Icy Saturnian satellites during the nominal mission of the Cassini spacecraft between 2004 and 2008. These images were used to create high-resolution mosaics of these satellites. The Cassini mission is expected to continue till 2017 and high-re…
A geological characterization of Ligeia Mare in the northern polar region of Titan
Chevrier, V. F.; Wasiak, F. C.; Androes, D. +3 more
Ligeia Mare, the second largest sea on Titan, resides in an endorheic basin dominated by seas in the northeastern polar region. Ligeia's shoreline morphology resembles terrestrial man-made reservoirs where water is dammed and valleys are flooded. Here we describe the mare and surrounding geologically diverse terrain including rugged highlands and …
The two-micron spectral characteristics of the Titanian haze derived from Cassini/VIMS solar occultation spectra
Kim, Sang Joon; Courtin, Régis; Sim, Chae Kyung +2 more
Vertically-resolved spectral characteristics of the Titanian haze in the 2-µm wavelength range were derived from solar occultation spectra measured by Cassini/VIMS on January 15, 2006. At the various altitudes probed by the solar occultation measurements, we reproduced the observed spectra using a radiative transfer program including absorpt…