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First year of coordinated science observations by Mars Express and ExoMars 2016 Trace Gas Orbiter
Gondet, B.; Ristic, B.; López-Valverde, M. A. +12 more
Two spacecraft launched and operated by the European Space Agency are currently performing observations in Mars orbit. For >15 years Mars Express has been conducting global surveys of the surface, the atmosphere and the plasma environment of the Red Planet. The Trace Gas Orbiter, the first element of the ExoMars programme, began its science pha…
Evolution of Saturn's north polar color and cloud structure between 2012 and 2017 inferred from Cassini VIMS and ISS observations
Baines, K. H.; Sromovsky, L. A.; Fry, P. M.
Cassini/ISS imagery and Cassini/VIMS spectral imaging observations from 0.35 to 5.12 µm show that Saturn's north polar region (70 °-90 ° N) evolved significantly between 2012 and 2017, with the region poleward of the hexagon changing from dark blue/green to a moderately brighter gold color, except for the inner eye region (88.2 °-90 ° N), wh…
Identification of a new spectral signature at 3 µm over Martian northern high latitudes: Implications for surface composition
Montmessin, Franck; Vincendon, Mathieu; Beck, Pierre +1 more
Mars northern polar latitudes are known to harbor an enhanced 3 µm spectral signature when observed from orbit. This may indicate a greater amount of surface adsorbed or bound water, although it has not yet been possible to easily reconcile orbital observations with ground measurements by Phoenix. Here we re-analyzed OMEGA/Mars Express obser…
Optical observations of near isotropic comet C/2006 OF2 (Broughton) at two different heliocentric distances
Lara, L.; Afanasiev, V.; Kulyk, I. +3 more
Spectra and images of comet C/2006 OF2 (Broughton) were obtained with the 4.2-m William Herschel Telescope (La Palma, Spain) and with the 6-m Big Telescope Alt-azimuth (SAO RAN, Russia) at two observing epochs on October 15, 2007 and December 05, 2008.The comet was at heliocentric distances of 4.24 au and 2.59 au before and after the perihelion, r…
The low electrical conductivity of Titan's lower atmosphere
Lorenz, Ralph D.
Titan's near-surface atmosphere, with a relatively high density and with weak ion production by cosmic rays or other sources, likely has a lower electrical conductivity than the Earth's, possibly <1 fS/m. Direct measurements by the Relaxation Probe on Huygens constrain it to be <0.5 pS/m, and extrapolation from higher altitudes suggests orde…
Modeling of observations of the OH nightglow in the Venusian mesosphere
Bougher, S. W.; Parkinson, C. D.; Yung, Y. L. +4 more
Venus airglow emissions have been unambiguously detected in the wavelength ranges of 1.40-1.49 and 2.6-3.14 µm in limb observations by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) onboard the Venus Express (VEx) spacecraft and are attributed to the OH(2-0) and OH(1-0) Meinel band transitions. The integrated (limb slant path…
Tropopause and lower stratosphere winds and eddy fluxes on Saturn as seen by Cassini imaging
Del Genio, Anthony D.; Barbara, John M.
An automated cloud feature tracking algorithm is applied to 2004 Cassini Imaging Science Subsystem images of Saturn's southern hemisphere and equatorial region (5°N-70°S) in continuum, methane band, and ultraviolet filters to derive zonal wind profiles and eddy momentum fluxes from the middle troposphere cloud tops to the lower stratosphere. Zonal…
Titan occultations of Orion's belt observed with Cassini/UVIS
Yelle, Roger V.; Koskinen, T. T.; Palmer, M. Y.
On 1 February 2016 Titan occulted the three stars in Orion's belt, as seen from the Casssini spacecraft. The ultraviolet spectrometer on Cassini observed this event with the stars arranged along the instrument's entrance slit. These three stellar occultations probed different latitudes in Titan's northern hemisphere but similar longitudes. The occ…
On the derivation of thermospheric temperatures from dayglow emissions on Mars
González-Galindo, Francisco; López-Valverde, Miguel Ángel; Forget, François +2 more
The Cameron bands and the UV doublet are two of the most prominent emission systems in the UV in Mars dayside. Their altitude variation has been exploited in the past to derive thermospheric temperatures from measurements obtained by the Mariner 6, 7, and 9 missions, the SPICAM instrument on board Mars Express, and the IUVS instrument on board MAV…
Asymmetrical meridional expansion of bright clouds from Saturn's 2010 great white storm
Dowling, Timothy E.; Li, Liming; Creecy, Ellen C. +4 more
Saturn's recurring great white storms play an important role in modifying its atmosphere. In 2010, such a storm with clouds encircling the planet occurred in the northern hemisphere. An interesting phenomenon of this storm is that the associated bright clouds expanded asymmetrically with respect to latitude, such that the southern boundary of the …