[PPS09-21] Impact-driven volatile loss from C-type chondrite-like materials
Keywords:C-type asteroids, Shock-induced devolatilization, Hypervelocity impact phenomena
The impact experiments were conducted using a two-stage light gas gun placed at Planetary Exploration Research Center of Chiba Institute of Technology (PERC/Chitech), Japan. We made pellets from the CI simulant and used as targets. In order to investigate the devolatilization behavior of the CI simulant, we used the two-valve method developed by Kurosawa et al. (2019). The method allows us to measure the chemical compositions of the shock-generated gas in an open system with a small risk of chemical contamination from the gun operation. The generated gases were measured by a quadrupole mass spectrometer (QMS). We performed 3 shots at nearly identical impact velocities around 5.8 km/s. An Al2O3 sphere was used as a projectile. We detected a variety of gases, which are H2, CH4, CO, H2S, and CO2, after the shots. The main product was CO2 at all the shots. The mass of produced CO2 was calculated to be 1-2 wt% of the projectile mass after the calibration of the systems. The results suggest that impact-driven volatile loss from C-type asteroids may not be so efficient if the assumption that CI simulant is a good analog of the constituent materials of C-type asteroids is correct.
Acnowledgement: We used the iSALE-2D shock physics code to interpret the experimental results. We appreciate the developers of iSALE, including G. Collins, K. Wünnemann, B. Ivanov, J. Melosh, and D. Elbeshausen. We also thank Tom Davison for the development of the pySALEPlot.