Search Publications
Investigation of water signatures at gully-exposed sites on Mars by hyperspectral image analysis
Schulze-Makuch, Dirk; Fan, Chaojun; Xie, Hongjie +1 more
High-resolution images from the Mars Obiter Camera (MOC) onboard the Mars Global Surveyor (MGS) show a variety of gully features on sloped surfaces of Mars. The mechanism of gully formation is still under debate, although a majority of studies tend to favor a mechanism related to liquid water flow based on geomorphology and fluid mechanics conside…
Discriminating contamination from particle components in spectra of Cassini's dust detector CDA
Kempf, S.; Postberg, F.; Srama, R. +5 more
The Chemical Analyser subsystem of the Cosmic Dust Analyser (CDA) aboard the Cassini spacecraft performs in situ measurements of the chemical composition of dust in space. The instrument records time-of-flight mass spectra of cations, extracted from the impact cloud that is created by high-velocity particle impacts onto the detector target. Thus, …
The effect of spacecraft radiation sources on electron moments from the Cassini CAPS electron spectrometer
Coates, Andrew J.; Arridge, Christopher S.; Jones, Geraint H. +5 more
Data from the Cassini plasma spectrometer (CAPS) electron spectrometer (ELS) have been found to be contaminated with an energy-independent background count rate which has been associated with radiation sources on Cassini. In this paper we describe this background radiation and quantitatively assess its impact on numerically integrated electron mom…
Titan's induced magnetosphere under non-ideal upstream conditions: 3D multi-species hybrid simulations
Simon, Sven; Motschmann, Uwe
A 3D, multi-species hybrid model (kinetic ions, fluid electrons) has been applied to the interaction between Saturn's largest satellite Titan and the plasma in the giant planet's outer magnetosphere. In contrast to the idealized picture deduced from Voyager 1 data, recent observations made by the Cassini magnetometer instrument suggest that the am…
Optical properties of dust from Jupiter family comets
Levasseur-Regourd, A. C.; Hadamcik, E.
To try to define specific physical properties of the dust of Jupiter-family comets (JFCs), we compare the light scattered by them. Amongst the more than 1000 JFCs, less than 200 are numbered, 40 of them being rather bright. In the present work we use data from the latter. In situ observations of three nuclei show low albedo surfaces. The albedo of…
Fog phenomena on Mars
Formisano, Vittorio; Möhlmann, Diedrich T. F.; Wolkenberg, Paulina +2 more
Mars Express High Resolution Stereo Camera (HRSC) images show impressive morning fog features in Valles Marineris and other regions of the surface of Mars. Temperatures have been determined, simultaneously to the imaging, by Mars Express Planetary Fourier Spectrometer (PFS). This identifies water ice rather than frozen CO 2 as the cause…
Old Faithful model for radiolytic gas-driven cryovolcanism at Enceladus
Rymer, Abigail M.; Sittler, Edward C.; Cooper, John F. +2 more
A new model is presented on how chemically driven cryovolcanism might contribute to episodic outgassing at the icy moon Enceladus and potentially elsewhere including Europa and Kuiper Belt Objects. Exposed water ices can become oxidized from radiolytic chemical alteration of near-surface water ice by space environment irradiation. In contact with …
Investigation of energetic proton penetration in Titan's atmosphere using the Cassini INCA instrument
Johnson, R. E.; Mitchell, D. G.; Smith, H. T. +1 more
Saturn's largest moon, Titan, provides an interesting opportunity to study how dense atmospheres interact with the surrounding plasma environment. Without an intrinsic magnetic field, this satellite's nitrogen-rich atmosphere is relatively unprotected from plasma interactions. Therefore, the energy-deposition rate is important for understanding ch…
The scientific rationale for the C1XS X-ray spectrometer on India's Chandrayaan-1 mission to the moon
Grande, M.; Koschny, D.; Rothery, D. A. +23 more
The UK-built Chandrayaan-1 X-ray Spectrometer (C1XS) will fly as an ESA instrument on India's Chandrayaan-1 mission to the Moon, launched in October 2008. C1XS builds on experience gained with the earlier D-CIXS instrument on SMART-1, but will be a scientifically much more capable instrument. Here we describe the scientific objectives of this inst…
Titan ionospheric conductivities from Cassini measurements
Garnier, P.; Wahlund, J. -E.; Ågren, K. +6 more
We present the first results of ionospheric conductivities at Titan based on measurements during 17 Titan flybys from the Cassini spacecraft. We identify an ionospheric region ranging from 1450±95km (approximately the location of the exobase) to approximately 1000 km where electrical currents perpendicular to the magnetic field may become importan…