Lunar crater ejecta: Physical properties revealed by radar and thermal infrared observations

R. R. Ghent, L. M. Carter, J. L. Bandfield, C. J. Tai Udovicic, B. A. Campbell

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

We investigate the physical properties, and changes through time, of lunar impact ejecta using radar and thermal infrared data. We use data from two instruments on the Lunar Reconnaissance Orbiter (LRO) - the Diviner thermal radiometer and the Miniature Radio Frequency (Mini-RF) radar instrument - together with Earth-based radar observations. We use this multiwavelength intercomparison to constrain block sizes and to distinguish surface from buried rocks in proximal ejecta deposits. We find that radar-detectable rocks buried within the upper meter of regolith can remain undisturbed by surface processes such as micrometeorite bombardment for >3 Gyr. We also investigate the thermophysical properties of radar-dark haloes, comprised of fine-grained, rock-poor ejecta distal to the blocky proximal ejecta. Using Diviner data, we confirm that the halo material is depleted in surface rocks, but show that it is otherwise thermophysically indistinct from background regolith. We also find that radar-dark haloes, like the blocky ejecta, remain visible in radar observations for craters with ages >3 Ga, indicating that regolith overturn processes cannot replenish their block populations on that timescale.

Original languageEnglish (US)
Pages (from-to)182-195
Number of pages14
JournalIcarus
Volume273
DOIs
StatePublished - Jul 15 2016
Externally publishedYes

Keywords

  • Cratering
  • Infrared observations
  • Moon
  • Radar observations
  • Regoliths

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint

Dive into the research topics of 'Lunar crater ejecta: Physical properties revealed by radar and thermal infrared observations'. Together they form a unique fingerprint.

Cite this