Search Publications
The radiative forcing variability caused by the changes of the upper cloud vertical structure in the Venus mesosphere
Pätzold, M.; Piccioni, G.; Ignatiev, N. I. +3 more
The upper cloud layer of Venus is a key factor affecting radiative energy balance of the mesosphere. Observations of the temperature and the cloud top structure by Venus Express revealed their strong variability with latitude. We used the 1-D radiative transfer model to study the dependence of the radiative forcing on the cloud top structure. The …
Inversion of sparse photometric data of asteroids using triaxial ellipsoid shape models and a Lommel-Seeliger scattering law
Cellino, A.; Hestroffer, D.; Muinonen, K. +1 more
The inversion of sparse photometric data of asteroids to derive from them information about the spin and shape properties of the objects is a hot topic in the era of the Gaia space mission. We have used a rigorous analytical treatment of the Lommel-Seeliger light-scattering law computed for the particular case of bodies having the shapes of ideal …
Characterization of the lower layer in the dayside Venus ionosphere and comparisons with Mars
Tellmann, Silvia; Pätzold, Martin; Häusler, Bernd +3 more
The influence of solar zenith angle (SZA) and solar irradiance has been well characterized for the V2 layer in the Venus ionosphere, but not the V1 layer, where previous efforts were limited by data scarcity and incomplete SZA coverage. Here we use more than 200 radio occultation profiles from Venus Express with good SZA coverage to characterize h…
Philae localization from CONSERT/Rosetta measurement
Kofman, Wlodek; Herique, Alain; Rogez, Yves +3 more
On 12 November 2014 at 15:34 UTC, after a 7-h descent, the Philae lander made contact with the surface of the comet Churyumov-Gerasimenko (67P/CG) in the centre of the intended landing zone. Following the failure of its anchoring systems, it bounced and continued to fly ballistically. A couple of hours later, telemetry transmitted to Rosetta showe…
The relationship between mesoscale circulation and cloud morphology at the upper cloud level of Venus from VMC/Venus Express
Ignatiev, N. I.; Rodin, A. V.; Markiewicz, W. J. +4 more
The Venus Monitoring Camera (VMC) acquired a set of ultraviolet (UV) images during the Venus Express mission unprecedented in its duration from May 2006 to September 2013. Here we present the results of digital tracking of the cloud features in the upper cloud layer at latitudes 25-75°S using images from 257 orbits with the best spatial coverage. …
Quantifying geological processes on Mars-Results of the high resolution stereo camera (HRSC) on Mars express
Mangold, N.; Jaumann, R.; Scholten, F. +35 more
This review summarizes the use of High Resolution Stereo Camera (HRSC) data as an instrumental tool and its application in the analysis of geological processes and landforms on Mars during the last 10 years of operation. High-resolution digital elevations models on a local to regional scale are the unique strength of the HRSC instrument. The analy…
COSIMA-Rosetta calibration for in situ characterization of 67P/Churyumov-Gerasimenko cometary inorganic compounds
Trieloff, Mario; Krüger, Harald; Fischer, Henning +15 more
COmetary Secondary Ion Mass Analyzer (COSIMA) is a time-of-flight secondary ion mass spectrometry (TOF-SIMS) instrument on board the Rosetta space mission. COSIMA has been designed to measure the composition of cometary dust particles. It has a mass resolution m/Δm of 1400 at mass 100 u, thus enabling the discrimination of inorganic mass peaks fro…
Distant ionospheric photoelectron energy peak observations at Venus
Coates, A. J.; Fedorov, A.; Barabash, S. +4 more
The dayside of the Venus ionosphere at the top of the planet's thick atmosphere is sustained by photoionization. The consequent photoelectrons may be identified by specific peaks in the energy spectrum at 20-30 eV which are mainly due to atomic oxygen photoionization. The ASPERA-4 electron spectrometer has an energy resolution designed to identify…
Remnant buried ice in the equatorial regions of Mars: Morphological indicators associated with the Arsia Mons tropical mountain glacier deposits
Head, James W.; Marchant, David R.; Scanlon, Kathleen E.
The fan-shaped deposit (FSD) on the western and northwestern flanks of Arsia Mons is the remnant of tropical mountain glaciers, deposited several tens to hundreds of millions of years ago during periods of high spin-axis obliquity. Previous workers have argued that the Smooth Facies in the FSD contains a core of ancient glacial ice. Here, we find …
Ionospheric photoelectrons at Venus: Case studies and first observation in the tail
Coates, A. J.; Fedorov, A.; Barabash, S. +5 more
The presence of photoelectrons in ionospheres, including that of unmagnetised Venus, can be inferred from their characteristic spectral peaks in the electron energy spectrum. The electrons within the peaks are created by the photoionisation of neutrals in the upper atmosphere by the solar HeII 30.4 nm line. Here, we present some case studies of ph…