Ammonia abundance in the coma of Halley's Comet

Journal Article · Fri Jul 01 00:00:00 EDT 1988 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/166488· OSTI ID:6920135

Marconi, M L; Mendis, D A

Consideration is given to recent work by Allen et al. (1987) which suggests that the value of the ratio of the abundance of the atomic masses 19 to 18 observed in situ in the inner coma of Comet Halley is incompatible with a pure H2O nucleus and requires an NH3 abundance of 1-2 percent. The present authors discuss possible ways of explaining the radial profile of r = 19/18, which deemphasizes the presence of NH3. It is shown that the observed value of the 19/18 mass ratio in the inner coma does not necessarily imply the existence of a significant abundance of NH3. An elevated UV flux, for which there is circumstantial evidence, could produce the same effect. 21 references.

• Research Organization: California Univ., San Diego (USA)
• OSTI ID: 6920135
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 330; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
AMMONIA
CHEMICAL COMPOSITION
COMETS
ELECTROMAGNETIC RADIATION
ELECTRON DENSITY
HALLEY COMET
HYDRIDES
HYDROGEN COMPOUNDS
IONIZATION
MORPHOLOGY
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OXYGEN COMPOUNDS
PHOTOIONIZATION
RADIATIONS
SOLAR FLUX
ULTRAVIOLET RADIATION
WATER