Search Publications
Beginning of activity in 67P/Churyumov-Gerasimenko and predictions for 2014-2015
Tubiana, C.; Snodgrass, C.; Bramich, D. M. +3 more
Context. Comet 67P/Churyumov-Gerasimenko was selected in 2003 as the new target of the Rosetta mission. It has since been the subject of a detailed campaign of observations to characterise its nucleus and activity.
Aims: We present previously unpublished data taken around the start of activity of the comet in 2007/8, before its last perihelio…
Revisiting cometary bow shock positions
Glassmeier, K. -H.; Richter, I.; Rubin, M. +2 more
The Rosetta spacecraft will arrive at comet 67P/Churyumov-Gerasimenko in 2014 and will escort the comet along its journey around the Sun. The predicted outgassing rate of the comet and the solar wind properties close to its perihelion at 1.24 AU lead to the expectation that a cometary bow shock will form during the escort phase. Since the forecast…
Phobos as a D-type Captured Asteroid, Spectral Modeling from 0.25 to 4.0 µm
Pajola, M.; Barbieri, C.; Bertini, I. +6 more
This paper describes the spectral modeling of the surface of Phobos in the wavelength range between 0.25 and 4.0 µm. We use complementary data to cover this spectral range: the OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System on board the ESA Rosetta spacecraft) reflectance spectrum that Pajola et al. merged with the VSK-KR…
Dusty Plasma Effects in Comets: Expectations for Rosetta
Mendis, D. A.; Horányi, M.
Despite their small masses, comets have played an extraordinary role in enhancing our understanding of cosmic physics. It was the calculation of comet Halley's orbit and the successful prediction of its return in 1758 that firmly established the correctness of Newton's law of universal gravitation. It was the morphology of the dusty tails of comet…
Predictions of Ion Production Rates and Ion Number Densities within the Diamagnetic Cavity of Comet 67P/Churyumov-Gerasimenko at Perihelion
Vigren, E.; Galand, M.
We present a one-dimensional ion chemistry model of the diamagnetic cavity of comet 67P/Churyumov-Gerasimenko, the target comet for the ESA Rosetta mission. We solve the continuity equations for ionospheric species and predict number densities of electrons and selected ions considering only gas-phase reactions. We apply the model to the subsolar d…
Importance of thermal reactivity for hexamethylenetetramine formation from simulated interstellar ices
Vinogradoff, V.; Duvernay, F.; Danger, G. +5 more
Context. Complex organic molecules are observed in a broad variety of astrophysical objects, but little is known about their formation mechanism. Laboratory simulations on interstellar ice analogues are therefore crucial for understanding the origin of these complex organic molecules. In this context, we focus on the thermal reactivity for the for…
Spin and activity of comet 67P/Churyumov-Gerasimenko
Lara, L. M.; Sierks, H.; Vincent, J. -B. +2 more
Aims: In 2014 ESA's spacecraft Rosetta will reach its final target: comet 67P/Churyumov-Gerasimenko (67P). Although this comet has been studied in great detail over the past decade, there are still some uncertainties regarding the actual spin orientation and the distribution of active regions on the surface. We here give an overview of our cu…
Reconciling main belt asteroid spectral flux density measurements with a self-consistent thermophysical model
Choukroun, Mathieu; Janssen, Michael; Keihm, Stephen +4 more
Thermophysical models consistent with Earth’s Moon and infrared and submillimeter measurements obtained during the Rosetta fly-by of Asteroid (21) Lutetia have been applied to computations of thermal fluxes from Asteroids (4) Vesta, (1) Ceres, (2) Pallas, and (10) Hygiea. Comparisons are made with Earth- and space-based flux measurements that cove…
Gas-phase Sequestration of Noble Gases in the Protosolar Nebula: Possible Consequences on the Outer Solar System Composition
Mousis, O.; Ali-Dib, M.; Pauzat, F. +2 more
We address the problem of the sequestration of Ar, Kr, and Xe by H_3^+ in the gas-phase conditions encountered during the cooling of protoplanetary disks when H_3^+ is competing with other species present in the same environment. Using high-level ab initio simulations, we try to quantify other sequestration possibilities involving He, H_5^+, H
Modeling of meteoroid streams: The velocity of ejection of meteoroids from comets (a review)
Ryabova, G. O.
An analytical review of the models of ejection of meteoroids from cometary nuclei is presented. Different formulas for the ejection velocity of meteoroids and the corresponding parameters are discussed and compared with the use of comet Halley and the Geminids meteoroid stream as examples. The ejection velocities obtained from observations of the …