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Ammonia in comet P/HalleyIn comet P/Halley the abundances of ammonia relative to water reported in the literature differ by about one order of magnitude from roughly 0.1% up to 2%. Different observational techniques seem to have inherent systematic errors. Using the ion mass channels m/q = 19 amu/e, 18 amu/e and 17 amu/e of the Neutral Mass Spectrometer experiment aboard the spacecraft Giotto, we derive a production rate of ammonia of (1.5(sub -0.7)(sup +0.5))% relative to water. Inside the contact surface we can explain our data by a nuclear source only. The uncertainty in our abundance of ammonia is primarily a result of uncertainties in some key reaction coefficients. We discuss in detail these reactions and the range of error indicated results from extreme assumptions in the rate coefficients. From our data, even in the worst case, we can exclude the ammonia abundance to be only of the order of a few per mill.
Document ID
19950057183
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Meier, R.
(Univ. of Bern Bern, Switzerland)
Eberhardt, P.
(Univ. of Bern Bern, Switzerland)
Krankowsky, D.
(Max Planck Inst. fuer Kernphysik Heidelberg, Germany)
Hodges, R. R.
(Univ. of Texas at Dallas, Richardson, TX United States)
Date Acquired
August 16, 2013
Publication Date
July 1, 1994
Publication Information
Publication: Astronomy and Astrophysics
Volume: 287
Issue: 1
ISSN: 0004-6361
Subject Category
Astrophysics
Accession Number
95A88782
Funding Number(s)
CONTRACT_GRANT: NAGW-1665
Distribution Limits
Public
Copyright
Other

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