Three-dimensional kinetic modeling of the neutral and charged dust in the coma of Rosetta’s target comet 67P/Churyumov-Gerasimenko
Abstract
Rosetta is the first mission that escorts a comet along its way through the Solar System for an extended amount of time. As a result, the target of the mission, comet 67P/Churyumov-Gerasimenko, is an object of great scientific interest.Dust ejected from the nucleus is entrained into the coma by the escaping gas. Interacting with the ambient plasma the dust particles are charged by the electron and ion collection currents. The photo and secondary emission currents can also change the particle charge. The resulting Lorentz force together with the gas drag, gravity, and radiation pressure define the dust particle trajectories.At altitudes comparable to those of the Rosetta trajectory, direction of a dust particle velocity can be significantly different from that in the innermost vicinity of the coma near the nucleus. At such altitudes the angular distribution of the dust grains velocity has a pronounced tail-like structure. This is consistent with Rosetta’s GIADA dust observations showing dust grains moving in the anti-sunward direction.Here, we present results of our model study of the neutral and charged dust in the coma of comet 67P/Churyumov-Gerasimenko, combining the University of Michigan AMPS kinetic particle model and the BATSRUS MHD model. Trajectories of dust particles within the observable size range of Rosetta’s GIADA dust instrument have been calculated accounting for the radiation pressure, gas drag, the nucleus gravity, the Lorentz force, and the effect of the nucleus rotation. The dust grain electric charge is calculated by balancing the collection currents at the grain’s location. We present angular velocity distribution maps of these charged dust grains for a few locations representative of Rosetta's trajectory around the comet.This work was supported by US Rosetta project contracts JPL-1266313 and JPL-1266314 and NASA Planetary Atmospheres grant NNX14AG84G
- Publication:
-
AAS/Division for Planetary Sciences Meeting Abstracts #47
- Pub Date:
- November 2015
- Bibcode:
- 2015DPS....4750309T