Search Publications
Production of neutral species in Titan's ionosphere through dissociative recombination of ions
Carrasco, Nathalie; Plessis, Sylvain; Dobrijevic, Michel +1 more
The production rates of neutral species by dissociative recombination (DR) of molecular ions with electrons in the ionosphere of Titan are quantified by a new model, including, for the first time, all the available kinetic data on this process. The calculation is based on the ion densities measured by the INMS instrument on Cassini orbiter during …
Solar migrating atmospheric tides in the winds of the polar region of Venus
Hueso, R.; Sánchez-Lavega, A.; Drossart, P. +5 more
We study the effects of migrating solar tides on the winds at the cloud tops of the polar region of Venus. The winds were measured using cloud tracking on images obtained at wavelengths of 3.9 and 5.0 µm by the instrument VIRTIS-M onboard Venus Express. These wavelengths probe about the same altitude close to the cloud tops, allowing for the…
Atomic oxygen distributions in the Venus thermosphere: Comparisons between Venus Express observations and global model simulations
Gérard, J. -C.; Soret, L.; Brecht, A. S. +1 more
Nightglow emissions provide insight into the global thermospheric circulation, specifically in the transition region (∼70-120 km). The O 2 IR nightglow statistical map created from Venus Express (VEx) Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) observations has been used to deduce a three-dimensional atomic oxygen density…
Automated cloud tracking system for the Akatsuki Venus Climate Orbiter data
Imamura, Takeshi; Takagi, Masahiro; Kouyama, Toru +3 more
Japanese Venus Climate Orbiter, Akatsuki, is cruising to approach to Venus again although its first Venus orbital insertion (VOI) has been failed. At present, we focus on the next opportunity of VOI and the following scientific observations.We have constructed an automated cloud tracking system for processing data obtained by Akatsuki in the prese…
Saturn’s high degree magnetic moments: Evidence for a unique planetary dynamo
Cao, Hao; Dougherty, Michele K.; Russell, Christopher T. +2 more
Saturn’s intrinsic magnetic field has long been known to be highly axisymmetric. None of the existing field models goes beyond spherical harmonic degree 3. In this paper, we assume that the axisymmetry extends to higher degrees. This allows us to derive the degree 4 and 5 axial moments by searching their parameter space based on the Cassini Saturn…
Hydrogen density in the dayside venusian exosphere derived from Lyman-α observations by SPICAV on Venus Express
Bertaux, J. -L.; Chaufray, J. -Y.; Leblanc, F. +2 more
A series of observations of the venusian hydrogen corona made by SPICAV on Venus Express are analyzed to estimate the amount of hydrogen in the exosphere of Venus. These observations were made between November 2006 and July 2007 at altitudes from 1000 km to 8000 km on the dayside. The Lyman-α brightness profiles derived are reproduced by the sum o…
Sunlight refraction in the mesosphere of Venus during the transit on June 8th, 2004
Rondi, S.; Sütterlin, P.; Tanga, P. +6 more
Many observers in the past gave detailed descriptions of the telescopic aspect of Venus during its extremely rare transits across the Solar disk. In particular, at the ingress and egress, the portion of the planet’s disk outside the Solar photosphere has been repeatedly perceived as outlined by a thin, bright arc (“aureole”). Those historical visu…
The O2 nightglow in the martian atmosphere by SPICAM onboard of Mars-Express
Gondet, B.; Reberac, A.; Montmessin, F. +5 more
We present observations of the O2(a1Δg) nightglow at 1.27 µm on Mars using the SPICAM IR spectrometer onboard of the Mars Express orbiter. In contrast to the O2(a1Δg) dayglow that results from the ozone photodissociation, the O2(a1Δg) nightglow…
A predator-prey model for moon-triggered clumping in Saturn's rings
Colwell, Joshua E.; Esposito, Larry W.; Sremčević, Miodrag +4 more
UVIS occultation data show clumping in Saturn's F ring and at the B ring outer edge, indicating aggregation and disaggregation at these locations that are perturbed by Prometheus and by Mimas. The inferred timescales range from hours to months. Occultation profiles of the edge show wide variability, indicating perturbations by local mass aggregati…
Tidal control of jet eruptions on Enceladus as observed by Cassini ISS between 2005 and 2007
Spitale, J. N.; Helfenstein, P.; Hurford, T. A.
Observations of Enceladus have revealed active jets of material erupting from cracks on its south polar surface. It has previously been proposed that diurnal tidal stress, driven by Enceladus' orbital eccentricity, may actively produce surface movement along these cracks daily and thus may regulate when eruptions occur. Our analysis of the stress …