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].
Cite
@article{arxiv.1903.05574,
title = {Reorientation of Sputnik Planitia implies a Subsurface Ocean on Pluto},
author = {F. Nimmo and D. P. Hamilton and W. B. McKinnon P. M. Schenk and R. P. Binzel and C. J. Bierson and R. A. Beyer and J. M. Moore and S. A. Stern and H. A. Weaver and C. Olkin and L. A. Young and K. E. Smith and J. R. Spencer and M. Buie and B. Buratti and A. Cheng and D. Cruikshank and C. Dalle Ore and A. Earle and R. Gladstone and W. Grundy and A. D. Howard and T. Lauer and I. Linscott and J. Parker and S. Porter and H. Reitsema and D. Reuter and J. H. Roberts and S. Robbins and M. Showalter and K. Singer and D. Strobel and M. Summers and L. Tyler and H. Weaver and O. L. White and O. M. Umurhan and M. Banks and O. Barnouin and V. Bray and B. Carcich and A. Chaikin and C. Chavez and C. Conrad and C. Howett and J. Hofgartner and J. Kammer and C. Lisse and A. Marcotte and A. Parker and K. Retherford and M. Saina and K. Runyon and R. Schindhelm and J. Stansberry and A. Steffl and T. Stryk and . H. Throop and C. Tsang and A. Verbiscer and H. Winters and A. Zangari},
journal= {arXiv preprint arXiv:1903.05574},
year = {2021}
}