Search Publications
On distribution of CMEs speed in solar cycle 23
Mittal, Nishant; Sharma, Joginder; Tomar, Vivek +1 more
We have analyzed the data for more than 12900 coronal mass ejections (CMEs) which were obtained by SOHO/LASCO during the period of 1996-2007. The online CME catalogue contains all major CMEs detected by LASCO C2 and C3 coronagraphs. Basically we determine the CME speeds from the linear and quadratic fits to the height-time measurements. It is foun…
Chandrayaan-1 X-ray Spectrometer (C1XS)—Instrument design and technical details
Grande, M.; Huovelin, J.; Howe, C. J. +13 more
The UK-built Chandrayaan-1 X-ray Spectrometer (C1XS) is flying as an ESA instrument on India's Chandrayaan-1 mission to the Moon. The Chandrayaan-1 mission launched on the 22nd October 2008 and entered a 100 km polar lunar orbit on the 12th November 2008. C1XS builds on experience gained with the earlier D-CIXS instrument on SMART-1, but will be a…
In situ radiometric dating on Mars: Investigation of the feasibility of K-Ar dating using flight-type mass and X-ray spectrometers
Barber, S.; Talboys, D. L.; Bridges, J. C. +9 more
The absolute chronology of Mars is poorly known and, as a consequence, a key science aim is to perform accurate radiometric dating of martian geological materials. The scientific benefits of in situ radiometric dating are significant and arguably of most importance is the calibration of the martian cratering rate, similar to what has been achieved…
Simultaneous measurements of Martian plasma boundaries by Rosetta and Mars Express
Barabash, S.; Lundin, R.; Fränz, M. +15 more
We present the first two-spacecraft near-simultaneous observations of the Martian bow shock (BS), magnetic pileup boundary (MPB) and photo-electron boundary (PEB) obtained by the plasma instruments onboard Rosetta and Mars Express during the Rosetta Mars flyby on February 25, 2007. Our observations are compared with shape models for the BS and MPB…
Water ice clouds in the Martian atmosphere: Two Martian years of SPICAM nadir UV measurements
Fussen, D.; Mateshvili, N.; Vanhellemont, F. +4 more
The SPICAM instrument onboard Mars Express has successfully performed two Martian years (MY 27 and MY28) of observations. Water ice cloud optical depths spatial and temporal distribution was retrieved from nadir measurements in the wavelength range 300-320 nm. During the northern spring the cloud hazes complex distribution was monitored. The cloud…
Ionospheric corrections of MARSIS subsurface sounding signals with filters including collision frequency
Nielsen, Erling; Orosei, Roberto; Zhang, Zhenfei +2 more
Ionospheric corrections of Mars advanced radar for subsurface and ionosphere sounding (MARSIS) subsurface sounding signals are necessary before they can be further analyzed. Usually the ionosphere correction only considers the phase dispersion owing to the electron densities. In this paper we show that if the electron-neutral collision frequency i…
OMEGA long wavelength channel: Data reduction during non-nominal stages
Bibring, Jean-Pierre; Langevin, Yves; Gondet, Brigitte +4 more
The Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité (OMEGA) instrument is a visible and near-infrared imaging spectrometer on board the European Mars Express (MEx) mission. The on-board calibration (OBC) performed at the beginning of observations on each orbit reveals that the photometric response of the C channel (1.0-2.5 µ…
Probing the internal structure of the nuclei of comets
Lasue, J.; Levasseur-Regourd, A. C.; Hadamcik, E. +1 more
There is no direct evidence about the internal structure of cometary nuclei, which are mostly hidden by their gas and dust comae, and have not yet been orbited by any spacecraft. Their densities are low, typically of about 400 kg m -3 for 9P/Tempel 1 (that was impacted by the Deep Impact probe) and 67P/Churyumov-Gerasimenko (that is the…
Evidence for condensed-phase methane enhancement over Xanadu on Titan
Barnes, J. W.; de Pater, I.; Hartung, M. +1 more
We present evidence for condensed-phase methane precipitation near Xanadu using nine nights of observations from the SINFONI integral-field spectrograph at the Very Large Telescope and imaging analysis with empirical surface subtraction. Radiative transfer models are used to support the imaging technique by simulating the spectrometer datacubes an…
The nuclei of Jupiter family comets: A critical review of our present knowledge
Thomas, Nicolas
Of the currently over 300 identified Jupiter family comets (JFCs), we have estimated nucleus sizes and shapes for fewer than 70 and have detailed nucleus observations arising from spacecraft fly-bys for just 3: 19P/Borrelly (Deep Space 1), 81P/Wild 2 (Stardust), and 9P/Tempel 1 (Deep Impact). These observations reveal similarities but also signifi…