Reorientation of Sputnik Planitia implies a subsurface ocean on Pluto
Author(s)Nimmo, F.; Hamilton, D. P.; McKinnon, W. B.; Schenk, P. M.; Binzel, Richard P.; Bierson, C. J.; Beyer, R. A.; Moore, J. M.; Stern, S. A.; Weaver, H. A.; Olkin, C. B.; Young, L. A.; Smith, K. E.; New Horizons Geology, Geophysics and Imaging Theme Team; ... Show more Show less
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The deep nitrogen-covered basin on Pluto, informally named Sputnik Planitia, is located very close to the longitude of Pluto's tidal axis and may be an impact feature, by analogy with other large basins in the Solar System. Reorientation of Sputnik Planitia arising from tidal and rotational torques can explain the basin's present-day location, but requires the feature to be a positive gravity anomaly, despite its negative topography. Here we argue that if Sputnik Planitia did indeed form as a result of an impact and if Pluto possesses a subsurface ocean, the required positive gravity anomaly would naturally result because of shell thinning and ocean uplift, followed by later modest nitrogen deposition. Without a subsurface ocean, a positive gravity anomaly requires an implausibly thick nitrogen layer (exceeding 40 kilometres). To prolong the lifetime of such a subsurface ocean to the present day and to maintain ocean uplift, a rigid, conductive water-ice shell is required. Because nitrogen deposition is latitude-dependent, nitrogen loading and reorientation may have exhibited complex feedbacks.
DepartmentMassachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Springer Science and Business Media LLC
Nimmo, F. et al. "Reorientation of Sputnik Planitia implies a subsurface ocean on Pluto." Nature 540, 7631 (November 2016): 94-96 © 2016 Macmillan Publishers Limited, part of Springer Nature
Author's final manuscript