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Reorientation of Sputnik Planitia implies a subsurface ocean on Pluto

2016; Nature Portfolio; Volume: 540; Issue: 7631 Linguagem: Inglês

10.1038/nature20148

1476-4687

F. Nimmo, Douglas P. Hamilton, W. B. McKinnon, P. Schenk, Richard P. Binzel, C. J. Bierson, R. A. Beyer, J. M. Moore, S. A. Stern, H. A. Weaver, C. B. Olkin, L. A. Young, K. Ennico Smith, J. M. Moore, W. B. McKinnon, J. R. Spencer, R. A. Beyer, Richard P. Binzel, M. W. Buie, B. Buratti, Andrew Cheng, D. P. Cruikshank, C. M. Dalle Ore, A. M. Earle, G. R. Gladstone, W. M. Grundy, A. D. Howard, Tod R. Lauer, Ivan Linscott, F. Nimmo, J. W. Parker, Simon Porter, H. J. Reitsema, D. Reuter, J. H. Roberts, S. J. Robbins, P. Schenk, M. Showalter, K.E. Singer, D. F. Strobel, M. E. Summers, Len Tyler, O. L. White, O. M. Umurhan, M. E. Banks, O. Barnouin, V. J. Bray, B. Carcich, A. Chaikin, Cristian F. Chavez, C. Conrad, Douglas P. Hamilton, Carly Howett, J. D. Hofgartner, Joshua A. Kammer, C. M. Lisse, Annie Marcotte, A. H. Parker, K. D. Retherford, M. Saina, Kirby Runyon, Rebecca Schindhelm, J. A. Stansberry, A. J. Steffl, T. Stryk, H. B. Throop, C. C. C. Tsang, A. Verbiscer, Helene Winters, A. M. Zangari, S. A. Stern, H. A. Weaver, C. B. Olkin, L. A. Young, K. Ennico Smith,

Geology and Paleoclimatology Research

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.