Pioneer Venus Lyman-α Observations of Comet P/Giacobini-Zinner and the Life Expectancy of Cometary Hydrogen

  1. Thomas J. Birmingham and
  2. Alexander J. Dessler
  1. M.R. Combi1,
  2. A.I.F. Stewart2 and
  3. W.H. Smyth1

Published Online: 19 MAR 2013

DOI: 10.1029/SP027p0281

Comet Encounters

Comet Encounters

How to Cite

Combi, M.R., Stewart, A.I.F. and Smyth, W.H. (1988) Pioneer Venus Lyman-α Observations of Comet P/Giacobini-Zinner and the Life Expectancy of Cometary Hydrogen, in Comet Encounters (eds T. J. Birmingham and A. J. Dessler), American Geophysical Union, Washington, D.C.. doi: 10.1029/SP027p0281

Author Information

  1. 1

    Atmospheric and Environmental Research, Inc., Cambridge, MA

  2. 2

    Laboratory for Atmospheric & Space Physics and Department of Astrophysical, Planetary & Atmospheric Sciences, University of Colorado.

Publication History

  1. Published Online: 19 MAR 2013
  2. Published Print: 1 JAN 1988

ISBN Information

Print ISBN: 9780875902395

Online ISBN: 9781118668757

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Keywords:

  • Cometary hydrogen;
  • Comet P/Giacobini-Zinner;
  • Particle-trajectory model (PTM);
  • Solar Lyman data;
  • Solar wind

Summary

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 2.2×1028 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 2×105 to 3×106 s during the 42 days preceding the observation.