Date: Monday 16-Nov-2020
Time: 11:15-12:15
Location: Online via Zoom (link sent out to the PALS distribution list prior to the talk)
Speaker: Adeline Gicquel-Brodtke (UMD)
Title: Activity of comet 67P/Churyumov- Gerasimenko during the summer of 2015 with Rosetta
The ESA Rosetta spacecraft reached comet 67P/Churyumov-Gerasimenko (67P) in August 2014, and over the course of the 2.5-year mission, many outbursts were seen. Close to perihelion in August 2015, a display of 34 outbursts on 67P (Vincent et al. 2016) were observed with the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) and the Navigation Camera (NAVCAM).
We focused on a bright outburst observed with the OSIRIS camera on July 29, 2015 (Gicquel et al. 2017). Using a Direct Simulation Monte Carlo (DSMC) model of gas and dust trajectories close to the nucleus, we estimated what gas properties were needed to create the dust distribution seen in the images. We find that, to fit the dust data, the gas production rate should be about 10x higher at the source location of the outbursts than neighboring areas.
We improved on this initial effort by updating an existing Collisionless Gas Simulation at JPL to provide estimates for the water outgassing flux and gas temperature. We are improving our current dust simulation to account for optically thick conditions. We will assume different size distribution and compositions for the dust. This will allow us to better constrain the nature of the outburst (gas-to-dust ratio, distribution of gas and dust, radial profile, brightness) and the surface properties which shape the appearance of the outburst (e.g. size of the active region on the nucleus).
For further information contact PALS coordinator Dr. Lori Feaga at feaga@astro.umd.edu or (301)-405-1383.
SPECIAL ACCOMMODATIONS:Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.
