Reorientation of Sputnik Planitia implies a Subsurface Ocean on Pluto

Abstract

The deep nitrogen-covered Sputnik Planitia (SP; informal name) basin on Pluto is located very close to the longitude of Pluto's tidal axis[1] and may be an impact feature [2], by analogy with other large basins in the solar system[3,4]. Reorientation[5-7] due to tidal and rotational torques can explain SP's location, but requires it to be a positive gravity anomaly[7], despite its negative topography. Here we argue that if SP formed via impact and if Pluto possesses a subsurface ocean, a positive gravity anomaly would naturally result because of shell thinning and ocean uplift, followed by later modest N2 deposition. Without a subsurface ocean a positive gravity anomaly requires an implausibly thick N2 layer (greater than 40 km). A rigid, conductive ice shell is required to prolong such an ocean's lifetime to the present day[8] and maintain ocean uplift. Because N2 deposition is latitude-dependent[9], nitrogen loading and reorientation may have exhibited complex feedbacks[7].

References in corpus (1)

• Convection in a volatile nitrogen-ice-rich layer drives Pluto's geological vigor

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• Morphological Comparison of Blocks in Chaos Terrains on Pluto, Europa, and Mars
• Rotation of a rigid satellite with a fluid component. A new light onto Titan's obliquity
• New Constraints on Pluto's Sputnik Planitia Ice Sheet from a Coupled Reorientation-Climate Model
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• Deciphering Sub-Neptune Atmospheres: New Insights from Geochemical Models of TOI-270 d
• Surface Composition of Pluto's Kiladze Area and Relationship to Cryovolcanism
• Dynamic reorientation of tidally locked bodies: application to Pluto
• The Tidal-Thermal Evolution of the Pluto-Charon System
• Synchronisation of a tidal binary by inward orbital migration. The case of Pluto and Charon