Infrared emission by organic grains in the coma of comet Halley

  title={Infrared emission by organic grains in the coma of comet Halley},
  author={Christopher F. Chyba and Carl E. Sagan},
Spacecraft1 and ground-based2–5 observations of comet Halley in the near-infrared reveal a triple-peaked emission feature near 3.4 µm, characteristic of C–H stretching in hydrocarbons (–CH3 and –CH2– alkanes). Here we discuss transmission spectra of organic residues produced by laboratory irradiation of candidate cometary ices, which serve as the basis for a model of emitting cometary dust. The laboratory synthesis of solid organic residue from irradiated low-occupancy methane ice clathrate… 

Carbonaceous Compounds in Comets: Infrared Observations

The Comet Halley observations showed that carbon is a major component of the comet nucleus, with mass spectroscopic data giving near-cosmic C/O ratios. Gaseous and solid compounds were also observed

Terrestrial analysis of the organic component of comet dust.

  • S. Sandford
  • Physics, Geology
    Annual review of analytical chemistry
  • 2008
The nature of cometary organics is of great interest, both because these materials are thought to represent a reservoir of the original carbon-containing materials from which everything else in the authors' solar system was made andBecause these materials may have played key roles in the origin of life on Earth, it provides insights into the possible abundance of life elsewhere in the universe.

Coloration and darkening of methane clathrate and other ices by charged particle irradiation: applications to the outer solar system.

Preaccretional chemistry, exogenous materials, and endogenous organic chemistry all contribute to the spectral properties of icy satellites which accreted simple CH(O) molecules and Radiation darkening traces the deposition of mobilized or impact-exposed carbon-bearing volatiles on these satellites.

Irradiation Effects on Comets and Cometary Debris

For the last 10 years, many experimental results have been obtained on the chemical and physical changes induced by ion and electron irradiation of materials relevant to comets. Those results are