Composition comparison between Comets P/Halley and P/Brorsen-Metcalf

Michael A. DiSanti, Uwe Fink

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Comet P/Brorsen-Metcalf was observed at heliocentric and geocentric distances very similar to those of Comet P/Halley. Notable differences in both absolute production rates and relative composition were found. Production rate ratios were derived without recourse to a model, thus minimizing model-dependent uncertainties. It was found that the active sun produces 1.23 times more OI 6300-Å flux than the quiet sun for equal H2O production rates. Taking this effect into account, the water production rate of Comet P/Brorsen-Metcalf was about 15% that of P/Halley, for the same heliocentric distance. Even more severe was the depletion in the continuum flux, which was a factor of 20 weaker for P/Brorsen-Metcalf than for P/Halley, when both were compared with their respective H2O production rates. The relative abundances of NH2, C2 and CN, again compared with H2O, were about 41, 75, and 70% that of Comet P/Halley. Both the C2 and CN abundances did not increase as quickly with decreasing heliocentric distances as for P/Halley, which is probably linked to their partial origin from the dust which was so much weaker for P/Brorsen-Metcalf.

Original languageEnglish (US)
Pages (from-to)105-111
Number of pages7
Issue number1
StatePublished - May 1991

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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