Reorientation of Sputnik Planitia implies a Subsurface Ocean on Pluto
F. Nimmo, D.P. Hamilton, W.B. McKinnon P.M. Schenk, R.P. Binzel, C.J. Bierson, R.A. Beyer, J.M. Moore, S. A. Stern, H. A. Weaver, C. Olkin, L. A. Young, K. E. Smith (New Horizons Geology Geophysics and Imaging Theme Team), J.R. Spencer, M. Buie, B. Buratti, A. Cheng, D. Cruikshank, C. Dalle Ore, A. Earle, R. Gladstone, W. Grundy, A.D. Howard, T.Lauer, I. Linscott, J. Parker, S. Porter, H. Reitsema, D. Reuter, J.H. Roberts, S. Robbins, M. Showalter, K. Singer, D. Strobel, M. Summers, L. Tyler, H. Weaver, O.L. White, O.M. Umurhan, M. Banks, O. Barnouin, V. Bray, B. Carcich, A. Chaikin, C. Chavez, C. Conrad, C. Howett, J. Hofgartner, J. Kammer, C. Lisse, A. Marcotte, A. Parker, K. Retherford, M. Saina, K. Runyon, E. Schindhelm, J. Stansberry, A. Steffl, T. Stryk, . H. Throop, C. Tsang, A. Verbiscer, H. Winters, A. Zangari
(Submitted on 13 Mar 2019)
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].
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Journal reference: Pluto, Nature, 540, 94-96 (2016)
DOI: 10.1038/nature20148
Cite as: arXiv:1903.05574 [astro-ph.EP]
(or arXiv:1903.05574v1 [astro-ph.EP] for this version)
Submission history
From: Kelsi Singer [view email]
[v1] Wed, 13 Mar 2019 16:19:20 UTC (622 KB)
