The neutron signature of Mercury's volatile polar deposits


  • W. C. Feldman,

  • B. L. Barraclough,

  • C. J. Hansen,

  • A. L. Sprague


Neutron leakage flux spectra are simulated to explore whether the nature of volatile deposits residing within the permanently shaded craters near the poles of Mercury can be identified using state-of-the-art space neutron detection techniques deployed aboard a flyby mission to Mercury. The most sensitive method for discriminating between H2O (ice)-rich and S-rich deposits involves measurement of the flux of epithermal neutrons. We conclude that a single flyby over crater Chao Meng-Fu at an altitude of 200 km is sufficient to detect a circular deposit rich in elemental sulfur at the 2.6σ statistical significance level, and that a similar deposit rich in H2O can be identified at the 7.8σ level. Whereas identification of a S-rich deposit is not unique but compelling because of auxiliary physical arguments, that of an H2O deposit is unique.