Heidelberg 2006 – scientific programme
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EP: Extraterrestrische Physik
EP 20: Monde, Ringe und kleine Körper
EP 20.2: Fachvortrag
Thursday, March 16, 2006, 17:00–17:15, B
Mm-sized dust grains in the trail of comet 67P/Churyumov-Gerasimenko: observation and modelling — •Jessica Agarwal1, Michael Mueller2, Hermann Boehnhardt3, and Eberhard Gruen1,4 — 1MPI-K, Saupfercheckweg 1, 69117 Heidelberg — 2EDS-Deutschland, ESA/ESOC, Robert-Bosch-Str. 5, 64293 Darmstadt — 3MPS, Max-Planck-Str. 2, 37191 Katlenburg-Lindau — 4HIGP, University of Hawaii,1680 East West Road POST 512c, Honolulu, HI 96822, USA
We present optical and infrared (24 µm) imaging data of the dust trail of comet 67P/Churyumov-Gerasimenko, obtained with the Wide Field Imager at the MPG/ESO 2.2m telescope in La Silla and with NASA’s Spitzer Space Telescope, respectively. Based on these images, we constrain the size distribution and material properties of mm-sized dust grains emitted from the comet. These particles remain close to the comet’s orbit because of weak radiation pressure and low emission speeds, thereby forming the comet’s dust trail. Such particles contain a significant fraction of the total mass which a comet contributes to the interplanetary dust environment. We evaluate the size distribution of the trail particles by fitting simulated images to the measured intensities. As far as possible, the model parameters are derived from the observed emission history of Churyumov-Gerasimenko. The size distribution is a crucial parameter for estimating the number density of large particles in the neighbourhood of the comet nucleus and for the safety of ESA’s Rosetta spacecraft which will pass through the trail region on its approach to Churyumov-Gerasimenko in 2013.