Search Publications

From Interstellar Dust to Comets: A Unification of Observational Constraints

Greenberg, J. Mayo; Hage, J. I.

The interstellar dust model of comets is numerically worked out to satisfy simultaneously several basic constraints provided by observations of Comet Halley, and to derive the porosity of coma dust. The observational constraints are (1) the strengths of the 3.4 and 9.7 micron emission bands, (2) the shape of the 9.7 micron band, (3) the amount of …

The Identification of H 3S + with the Ion of Mass per Charge (m/q) 35 Observed in the Coma of Comet Halley

Reme, H.; Korth, A.; Lin, R. P. +3 more

A sharp peak in the mass spectrum at 35 amu is observed by the heavy ion analyzer on board the Giotto spacecraft just inside the ionopause. This peak is identified with H3S(+) and it is argued that the dominant source of its likely parent molecule (H2S) is the observed distributed source of circumnuclear dust, rather than the central nucleus. In t…

Hydrogenated Amorphous Carbon Grains in Comet Halley?

Colangeli, L.; Fonti, S.; Bussoletti, E. +3 more

Recent IR observations of Comets Halley, Wilson, and Bradfield have shown the existence of an emission feature falling at around 3.4 microns. In this paper, it is shown that a good fit of both the IR continuum and the band can be obtained by assuming a simple thermal emission model based upon the optical properties of hydrogenated amorphous carbon…