Search Publications
Variable winds on Venus mapped in three dimensions
Baines, K. H.; Hueso, R.; Sánchez-Lavega, A. +9 more
We present zonal and meridional wind measurements at three altitude levels within the cloud layers of Venus from cloud tracking using images taken with the VIRTIS instrument on board Venus Express. At low latitudes, zonal winds in the Southern hemisphere are nearly constant with latitude with westward velocities of 105 ms-1 at cloud-top…
Mars Express and Venus Express multi-point observations of geoeffective solar flare events in December 2006
Coates, A. J.; Kallio, E.; Fedorov, A. +50 more
In December 2006, a single active region produced a series of proton solar flares, with X-ray class up to the X9.0 level, starting on 5 December 2006 at 10:35 UT. A feature of this X9.0 flare is that associated MeV particles were observed at Venus and Mars by Venus Express (VEX) and Mars Express (MEX), which were ∼80° and ∼125° east of the flare s…
Characteristic size and shape of the mirror mode structures in the solar wind at 0.72 AU
Russell, C. T.; Zhang, T. L.; Glassmeier, K. -H. +10 more
We investigate the structure of mirror modes in the solar wind at 0.72 AU using Venus Express magnetic field measurements. The mirror mode structure is identified as the presence of magnetic depression or magnetic ``holes'' in the solar wind with little or no directional change across them. We determine the characteristic size and shape of these s…
Initial Venus Express magnetic field observations of the Venus bow shock location at solar minimum
Barabash, S.; Russell, C. T.; Zhang, T. L. +10 more
In this study, magnetic field measurements obtained by the Venus Express spacecraft are used to determine the bow shock position at solar minimum. The best fit of bow shock location from solar zenith angle 20-120° gives a terminator bow shock location of 2.14 RV (1 RV=6052 km) which is 1600 km closer to Venus than the 2.40 R<…
HDO and H2O vertical distributions and isotopic ratio in the Venus mesosphere by Solar Occultation at Infrared spectrometer on board Venus Express
Montmessin, F.; Fedorova, A.; Korablev, O. +8 more
Vertical distributions of the molecular density and mixing ratios of H2O and HDO in the Venus mesosphere have been obtained using Solar Occultation at Infrared (SOIR), a high-resolution (with λ/δλ ~ 20,000) echelle spectrometer on Venus Express. The atmosphere is sounded in solar occultation in the range of altitudes from 65 to 130 km. …
Venus surface thermal emission at 1 µm in VIRTIS imaging observations: Evidence for variation of crust and mantle differentiation conditions
Erard, S.; Drossart, P.; Piccioni, G. +4 more
The Venus Express spacecraft images the nightside thermal emissions using the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS). At 1.02, 1.10, and 1.18 µm, thermal emission from the surface is observed. The signal is attenuated by scattering and absorption in the dense atmosphere. The measured flux at the top of the atmosphere is p…
Location of the bow shock and ion composition boundaries at Venus—initial determinations from Venus Express ASPERA-4
Coates, A. J.; Kallio, E.; Fedorov, A. +52 more
For the first time since 1992 when the Pioneer Venus Orbiter (PVO) ceased to operate, there is again a plasma instrument in orbit around Venus, namely the ASPERA-4 flown on Venus Express (inserted into an elliptical polar orbit about the planet on April 11, 2006). In this paper we report on measurements made by the ion and electron sensors of ASPE…
A latitudinal survey of CO, OCS, H2O, and SO2 in the lower atmosphere of Venus: Spectroscopic studies using VIRTIS-H
Drossart, P.; Piccioni, G.; Bézard, B. +3 more
The high-resolution channel (R $\simeq$ 2000) of the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument (VIRTIS-H) aboard Venus Express has provided numerous spectra of the nightside infrared thermal emission in the 2.3-µm window. Mixing ratios of various minor species in the 30-40 km range could therefore be inferred usin…
First detection of hydroxyl in the atmosphere of Venus
Gondet, B.; Erard, S.; Drossart, P. +41 more
Context: Airglow emissions, such as previously observed from NO and O2(a-X) (0-0) on Venus, provide insight into the chemical and dynamical processes that control the composition and energy balance in the upper atmospheres of planets. The OH airglow emission has been observed previously only in the Earth's atmosphere where it has been used to infe…
Ionospheric photoelectrons at Venus: Initial observations by ASPERA-4 ELS
Coates, A. J.; Kallio, E.; Fedorov, A. +46 more
We report the detection of electrons due to photo-ionization of atomic oxygen and carbon dioxide in the Venus atmosphere by solar helium 30.4 nm photons. The detection was by the Analyzer of Space Plasma and Energetic Atoms (ASPERA-4) Electron Spectrometer (ELS) on the Venus Express (VEx) European Space Agency (ESA) mission. Characteristic peaks i…