Nejdůležitější odborné publikace vydané během prvního období (do 31. března 2019). Seznam všech publikací výzkumného programu PARTPHYS vydaných v rámci projektu CAAS najdete v předchozím příspěvku.
Formation of methane and (per)chlorates on Mars
Svatopluk Civiš, Antonín Knížek, Paul B. Rimmer, Martin Ferus, Petr Kubelík, Markéta Zukalová, Ladislav Kavan, Elias Chatzitheodoridis
CS Earth Space Chem. 201932221-232, Publication Date:December 17, 2018
Methane, perchlorates, chlorates, and methyl chlorides have all been detected on Mars. The origin of these species has never been adequately explained. In this paper, we irradiated mixtures of CO2, HCl, and a mineral catalyst—anatase, rutile, montmorillonite, and the Nakhla meteorite—with soft UV radiation for up to 3500 h and observed the formation of perchlorates, chlorates, methyl chlorides, and methane in a single experiment. Additionally, the methanogenesis for anatase was observed at −196 °C. Further, we propose that while methane is decomposed relatively quickly and therefore attains a steady-state concentration (0.41 ± 0.16 ppbv), the chlorinated compounds are much more stable and therefore would have accumulated throughout the Martian history. We estimate that this mechanism would be sufficient in the course of Martian history to accumulate perchlorate in the soil in 0.5 wt % in 5–50 cm depth, which is in accordance with the observed perchlorate content on Mars. This predicted perchlorate gradient may be observed with the Insight rover. Further, if microbes are present on Mars, they will likely inhabit depths below the perchlorate (i.e., 5–50 cm). This chemistry likely still continues on Mars to a certain extent, and any future exploration by rovers or planetary models should account for this process during their analyses.
Anisotropic flow in Xe-Xe collisions at root s(NN)=5.44 TeV
Physics Letters B, Volume 784, 10 September 2018, Pages 82-95
The first measurements of anisotropic flow coefficients for mid-rapidity charged particles in Xe–Xe collisions at TeV are presented. Comparing these measurements to those from Pb–Pb collisions at TeV, is found to be suppressed for mid-central collisions at the same centrality, and enhanced for central collisions. The values of are generally larger in Xe–Xe than in Pb–Pb at a given centrality. These observations are consistent with expectations from hydrodynamic predictions. When both and are divided by their corresponding eccentricities for a variety of initial state models, they generally scale with transverse density when comparing Xe–Xe and Pb–Pb, with some deviations observed in central Xe–Xe and Pb–Pb collisions. These results assist in placing strong constraints on both the initial state geometry and medium response for relativistic heavy-ion collisions.