Detection of large grains in the coma of Comet C/2001 A2 (LINEAR) from Arecibo radar observations

Michael C. Nolan, John K. Harmon, Ellen S. Howell, Donald B. Campbell, Jean Luc Margot

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Arecibo S-band (λ = 13 cm) radar observations of Comet C/2001 A2 (LINEAR) on 2001 July 7-9 showed a strong echo from large coma grains. This echo was significantly depolarized. This is the first firm detection of depolarization in a grain-coma radar echo and indicates that the largest grains are at least λ/2π or 2 cm in radius. The grains are moving at tens of m s-1 with respect to the nucleus. The nondetection of the nucleus places an upper limit of 3 km on its diameter. The broad, asymmetric echo power spectrum suggests a fan of grains that have a steep (differential number ∼a-4) size distribution at cm-scales, though the observed fragmentation of this comet complicates that picture.

Original languageEnglish (US)
Pages (from-to)432-441
Number of pages10
Issue number2
StatePublished - Apr 2006
Externally publishedYes


  • Comets
  • Radar

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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