挥发性氮冰富集层的对流驱动了冥王星的地质活力
地球与行星天体物理
2021-09-06 v1
摘要
非正式命名为 Sputnik Planum 的广阔、深邃、充满挥发性冰的盆地是冥王星地质活动的核心[1,2]。其由分子氮、甲烷和一氧化碳冰组成[3]，但以 N2 冰为主，该冰层被组织为通常约 10–40 km 宽的单元或多边形，类似于固态对流的地表表现[1,2]。本文基于现有流变测量[4]报告，在冥王星估计的现今热流条件下，厚度约大于 1 km 的 N2 冰固态层应当发生对流。更重要的是，我们通过数值模拟表明，几公里厚的固态氮层中的对流翻转可解释这些单元的巨大横向宽度。N2 冰黏度的温度依赖性意味着 SP 冰层以所谓迟缓盖层（sluggish lid）机制对流[5]，这是一种此前未在太阳系中明确观测到的独特对流模式。平均地表水平速度几 cm/yr 意味着地表传输或更新时间约 500,000 年，远小于 Sputnik Planum 的 10 Myr 陨石坑保留年龄上限[2]。类似的通过对流更新地表也可能发生于柯伊伯带其他矮行星上，这可能有助于解释其中一些的高反照率。
引用
@article{arxiv.1903.05571,
title = {Convection in a volatile nitrogen-ice-rich layer drives Pluto's geological vigor},
author = {William B. McKinnon and Francis Nimmo and Teresa Wong and Paul M. Schenk and Oliver L. White and J. H. Roberts and J. M. Moore and J. R. Spencer and A. D. Howard and O. M. Umurhan and S. A. Stern and H. A. Weaver and C. B. Olkin and L. A. Young and K. E. Smith and R. Beyer and R. P. Binzel 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 T. Lauer and I. Linscott and J. Parker and S. Porter and H. Reitsema and D. Reuter and S. Robbins and M. Showalter and K. Singer and D. Strobel and M. Summers and L. Tyler and H. Weaver and M. Banks and O. Barnouin and V. Bray and B. Carcich and A. Chaikin and C. Chavez and C. Conrad and D. Hamilton 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:1903.05571},
year = {2021}
}