Héctor Martínez Rodríguez EUROPA’S ICY SURFACE Héctor Martínez Rodríguez Sistema Solar y Exoplanetas Mayo 2014

Overview  

Overview: Europa’s surface Outer layer of water around 100 km thick with an iced upper crust (geological evidences show a low viscosity layer beneath the surface). High albedo (0.64) Spectroscopic data are consistent with hydrated minerals, suggesting the presence of water on the surface in the past (NIMS) Few craters, tectonically active and young (tidal effects due to the resonances with Io and Jupiter) 200 km high water vapor plumes (high heat flow, HST, December 2013)

Overview: Europa’s surface  

Overview: Europa’s surface

Europa’s salty surface The less ice there is, the darker the surface is. Pure ice is shown in dark blue

Europa’s salty surface  

Europa’s salty surface

Europa’s surface: models The thickness of the shell is important to understand Europan geological features and processes: Chaos features Impact crater morphology Formation of ridges, bands and faults Convection

Europa’s surface: models  

Europa’s surface: models

Europa’s surface: thick-shell model  

Europa’s surface: thick-shell model  

Europa’s ocean  

Europa’s ocean Tidal heating essential to explain its existence Measurements of the librations of Europa characterise the ocean. The icy shell does not librate independently from the interior Potential for extraterrestrial life

Europa’s surface: resume

Europa’s surface: resume

References Billings, S. E., & Kattenhorn, S. A. 2005, Icarus 177 397–412 Goldreich, P. M., & Mitchell, J. L. 2010, arXiv:0910.0032v3 Hand, K. P., & Chyba, C.F. 2007, Icarus 189 424–438 Kargel, J. S. et al. 2000, Icarus 148, 226 –265 Priscu, J. C., & Hand, K.P. 2012, Microbe / Volume 7, Number 4

References Ruiz, J. 2012, Earth, Moon and Planets 109:117–125 Ruiz, J., & Fairén, A.G. 2005, Earth, Moon and Planets 97: 79–90 Ruiz, J., & Tejero, R. 2003, Icarus 162 362–373 Ruiz, J., & Tejero, R. 2005, Icarus 177 438–446

References http://science.nasa.gov/ http://hubblesite.org/ http://nineplanets.org/ http://solarviews.com/ http://www.planetary.org/