Rays and secondary craters of Tycho

Colin M. Dundas, Alfred S. McEwen

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

The large, fresh crater Tycho in the nearside lunar highlands has an extensive system of bright rays covering approximately 560,000 km2, containing dense clusters of secondary craters. Examination of crater densities in several clusters shows that Tycho produced almost 106 secondary craters larger than 63 m diameter. This is a lower limit, because small crater densities are reduced, most likely by mass wasting. We estimate a crater erasure rate of 2-6 cm/Myr, varying with crater size, and consistent with previous results. This process has removed many small craters, and it is probable that the original number of secondary craters formed by Tycho was higher. Also, we can only identify distant secondaries of Tycho where they occur in bright rays. Craters on Mars and Europa also formed large numbers of secondaries, but under possibly ideal conditions for spallation as a mechanism to produce high-velocity ejecta fragments. The results from Tycho show that large numbers of such fragments can be produced even from impact into a heavily fragmented target on which spallation is expected to be less important.

Original languageEnglish (US)
Pages (from-to)31-40
Number of pages10
JournalIcarus
Volume186
Issue number1
DOIs
StatePublished - Jan 2007

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craters
crater
rays
spallation
Tycho crater
fragments
Europa
highlands
mass wasting
ejecta
mars
coverings
Mars
examination
estimates

Keywords

  • Cratering
  • Impact processes
  • Moon

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Rays and secondary craters of Tycho. / Dundas, Colin M.; McEwen, Alfred S.

In: Icarus, Vol. 186, No. 1, 01.2007, p. 31-40.

Research output: Contribution to journalArticle

Dundas, Colin M. ; McEwen, Alfred S. / Rays and secondary craters of Tycho. In: Icarus. 2007 ; Vol. 186, No. 1. pp. 31-40.
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