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Pioneer Venus lyman‐α observations of comet P/Giacobini‐Zinner and the life expectancy of cometary hydrogen
Author(s) -
Combi M. R.,
Stewart A. I. F.,
Smyth W. H.
Publication year - 1986
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl013i004p00385
Subject(s) - venus , comet , physics , meteoroid , solar wind , comet tail , atmosphere of venus , astrobiology , astronomy , atmospheric sciences , plasma , quantum mechanics
Pioneer Venus observed the hydrogen coma of Comet P/Giacobini‐Zinner on 11 September 1985 during the ICE fly‐by. Analysis of these data with a time‐dependent 3‐D particle‐trajectory model implies a water production rate of 2.2 × 10 28 s −1 on that day. The model includes the irregular variations in the H lifetime and the H Lyman‐α fluorescence rate determined from simultaneous measurements of the solar wind by ICE and of the solar UV by SME, respectively. The H lifetime varied from 2 × 10 5 to 3 × 10 6 s during the 42 days preceding the observation.