Physical processes in cometsThe paper discusses physical processes in comets which involve solar and nuclear radial forces that affect the motions of gases and icy grains, gas-phase chemistry very close to the nuclei of large comets near the sun, sublimation of icy grains, dissociation of parent molecules into radicals and of radicals into atoms, and ionization by sunlight and collisions. The composition and dimensions of nuclei are examined along with variations in intrinsic brightness, the nature of volatiles, gas production rates in the coma, characteristics of icy grains in the coma, and the structure of streamers, ion tails, and dust tails. The structure of the coma is described in detail on the basis of spectroscopic observations of several comets. The origin of comets is briefly reviewed together with the relation of comets to earth, the interplanetary complex, and the interstellar medium. Desirable future observations are noted, especially by space missions to comets.
Document ID
19760063867
Acquisition Source
Legacy CDMS
Document Type
Other - Collected Works
Authors
Whipple, F. L. (Harvard College Observatory and Smithsonian Astrophysical Observatory Cambridge, Mass., United States)
Huebner, W. F. (California, University Los Alamos, N. Mex., United States)