EES Guest Speaker - Dr. Anton Ermakov
Dr. Anton Ermakov joins us this Friday to discuss "Ganymede and Europa as seen by Juno"
Ocean worlds have recently emerged as one of the most fascinating and important classes
of planetary bodies in the solar system. In this talk, Dr. Ermakov will focus on insights
that were unlocked by geophysical data from the Juno spacecraft during its flybys
of two such worlds: Ganymede and Europa. The gravity and magnetic data from Juno and
Galileo mission indicate that Ganymede is differentiated and heated principally by
the decay of radioactive isotopes in its silicate mantle. Ganymede hydrosphere is
divided into a likely ocean, a convective ice zone and an upper conductive ice region.
Non-hydrostatic gravity anomalies detected on Ganymede are a factor of four larger
than those observed on similarly sized Titan. Despite similar data quality, non-hydrostatic
gravity anomalies on Europa were not detected, indicating Europa’s interior cannot
maintain the same level of non-hydrostatic stress as Ganymede. Europa’s shell is likely
thinner than that of Ganymede yielding higher heat flux. Microwave Radiometry (MWR)
data show a drastic difference in the brightness temperature spectra between Europa
and Ganymede, which is indicative of the ice shell structures of these bodies. The
MWR data present larger geographic variations of brightness temperature on Ganymede
compared to Europa indicating a larger degree of spatial heterogeneity of Ganymede’s
shell. Ongoing analysis of the MWR data provides a new constraint on the shell’s thermal
structure, ice purity and distribution of internal reflections.
