Detection of Ammonia Suggests Recent Geological Activity on Pluto

Virgil Fossa, the red crack in the left image, may be a cryovolcano that erupted liquid water and ammonia onto Pluto’s surface. Red, yellow, orange and purple pixels in the right picture correspond to higher concentrations of ammonia in water ice. Credit: Dalle Ore et al., Science Advances 2019

Virgil Fossae, the red crack in the left image, may be a cryovolcano that erupted liquid water and ammonia onto Pluto’s surface. Red, yellow, orange and purple pixels in the right picture correspond to higher concentrations of ammonia in water ice. Credit: Dalle Ore et al., Science Advances 2019

In their recently published article in Science Advances, Dalle Ore and co-authors report the detection of ammonia (NH3) on Pluto’s surface in spectral images taken when the New Horizons spacecraft flew past the dwarf planet in July 2015. Ammonia was detected in a region of past tectonic activity called Virgil Fossae, where water ice is also an abundant phase. Because ammonia can be destroyed by ultraviolet radiation or ion bombardment, particularly when it occurs in water ice, its presence on a planetary surface suggests geologically recent deposition. The areal distribution of the ammonia-rich water ice is suggestive of liquid water erupting in a cryovolcano. These findings add to the evidence for ongoing geological activity on Pluto as well as the possible presence of liquid water at depth. READ MORE

 

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