Juno Measures Deep Water Abundance At Jupiter’s Equator 

• Jupiter’s water abundance in the equatorial region is ~2.7 X solar (1,2).
• Equatorial region chosen for initial estimate because it appears uniquely well mixed.
• Galileo Probe measured a depleted water abundance of ~0.4 X solar in the presence of 4X heavy element enrichment, inconsistent with planet formation scenarios. 
Jupiter’s North and Main Equatorial Zone from PJ-10. Credit : NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill 

• Major Surprise: Water & ammonia are not well mixed in Jupiter’s deep atmosphere. (3,4)
• Global water abundance critically constrains Jupiter’s formation & interior structure.
• Global water abundance may differ from that probed in the well-mixed equatorial region: other latitudes are under study to assess global water abundance.

1. Li et al., Nature Astronomy, 2019:  DOI: 10.1038/s41550-020-1009-3       
2. Using data from Juno’s first 9 orbits 
3. Bolton et al., Science, 2017: DOI: 10.1126/science.aal2108
4.Li et al., GRL, 2017: DOI: 10.1002/2017GL073159 
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