Titre du document

Secondary craters

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Nom du Corpus

AstroConcepts

Auteur(s)
  • Wayne A. Roberts
Affiliation(s)
  • The Boeing Company, Seattle, Washington ,USA
Résumé

Secondary craters formed by the impact of ejecta missiles generally occur outside the lip crest of explosion-induced shock craters. Numerous shallow depressions occurring in the region adjacent to the lunar crater Copernicus have also been interpreted as secondary craters. Missiles which produce secondary craters are:1. Comminuted and shock compacted material.2. Single rock or soil fragments.3. Fragments of structural material.4. Unconsolidated but discrete masses of crater ejecta.Superposition of ejecta layers, exposed of excavation of the large secondary craters near Sedan, indicates that unwinnowed material arrives first followed by the large masses of unconsolidated alluvium. The impact of these masses forms secondary craters that are essentially compressional features. The large masses are followed winnowed ejecta separated by passage through the atmosphere into a coarse fraction deposited as individual grains and a fine fraction that is deposited relatively slowly as long as the dust cloud remains in the area.The secondary craters observed on Earth have all been formed by missile impact ve velocities lower than the acoustic velocity of the medium; however, on the Moon, primary as well as secondary impact craters can be produced at both subsonic and hypersonic velocities. This indicates that the use of shock crater frequency to infer flux of larger meteorites may not be valid.

Langue(s) du document
Anglais
Année de publication
1964
Revue

Icarus

Éditeur
Elsevier
Type de publication
journal
Type de document
research-article
Présence de XML structuré
Non
Version de PDF
1.3
Score de qualité du texte
4.546
Nom du concept
  • Space debris
Catégories Science-Metrix
  • 1 - natural sciences ; 2 - physics & astronomy ; 3 - astronomy & astrophysics
Catégories Inist
  • 1 - sciences appliquees, technologies et medecines ; 2 - sciences exactes et technologie ; 3 - terre, ocean, espace ; 4 - sciences de la terre
Catégories Scopus
  • 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Space and Planetary Science
  • 1 - Physical Sciences ; 2 - Physics and Astronomy ; 3 - Astronomy and Astrophysics
Catégories WoS
  • 1 - science ; 2 - astronomy & astrophysics
Identifiant ISTEX
DC1AF1007F5D13ACB4534B71D986F9E6B7837D8C
ark:/67375/6H6-4DC90L1M-W
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