Abstract
The neutral mass spectrometer experiment (NMS) carried by the Giotto spacecraft was designed to determine the abundances and the chemical, elemental and isotopic composition of the gases and low-energy ions in the coma of comet Halley. Its first results show the predominance of water vapour (∼80% by volume). Preliminary evaluation of the data yields an H2O density of 4.7 × 107 molecules cm−3 at 1,000 km, a neutral gas expansion velocity of 0.9 km s−1 and a total gas production rate of 6.9 × 1029 molecules s−1. The photodestruction scale length for H2O was 3.9 × 104 km. Limits on the abundances of CO2, NH3 and CH4 relative to H2O are given. The contact surface was located at 4,700±200 km, as observed from a change in ion temperature. The water-group ions H3O+, H2O+ and OH+ have been unambiguously identified, along with the ions 12C+, 12CH+, 16O+, Na+, 12C2+, 32S+, 34S+ and 56Fe+. The 34S+/32S+ ratio is 0.045±0.010. General features of the low-energy ion flow at large distances from the nucleus are presented.
Enjoying our latest content?
Log in or create an account to continue
- Access the most recent journalism from Nature's award-winning team
- Explore the latest features & opinion covering groundbreaking research
or
References
Krankowsky, D. et al. Eur. Space Ag. spec. Publ. 1077, 109–128 (1986).
Huebner, W. F. & Carpenter, C. W. Los Alamos natn. Lab. Rep. No. LA-8085-MS (1979).
Marconi, L. M. & Mendis, D. A. Astrophys. J. 287, 445–454 (1984).
Bossy, L. & Nicolet, M. Planet. Space Sci. 29, 907–914 (1981).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Krankowsky, D., Lämmerzahl, P., Herrwerth, I. et al. In situ gas and ion measurements at comet Halley. Nature 321 (Suppl 6067), 326–329 (1986). https://doi.org/10.1038/321326a0
Received:
Accepted:
Issue date:
DOI: https://doi.org/10.1038/321326a0
This article is cited by
-
Chemical and Isotopic Composition Measurements on Atmospheric Probes Exploring Uranus and Neptune
Space Science Reviews (2020)
-
On the Origin and Evolution of the Material in 67P/Churyumov-Gerasimenko
Space Science Reviews (2020)
-
Infrared excitation processes of C2H6 in comets
Earth, Planets and Space (2014)
-
Large Dust Grains Around Cometary Nuclei
Earth, Moon, and Planets (2008)
-
RPC-IES: The Ion and Electron Sensor of the Rosetta Plasma Consortium
Space Science Reviews (2007)
