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Science 18 May 2001:
Vol. 292. no. 5520, pp. 1326 - 1329
DOI: 10.1126/science.1060858
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Reports

Water Production of Comet C/1999 S4 (LINEAR) Observed with the SWAN Instrument

J. Teemu T. Mäkinen,1* Jean-Loup Bertaux,2 Michael R. Combi,3 Eric Quémerais2

The SWAN (Solar Wind ANisotropies) Lyman-alpha all-sky camera on the SOHO spacecraft observed the hydrogen coma of comet C/1999 S4 (LINEAR) from the end of May through mid-August 2000. A systematic set of water-production rates was obtained for this well-documented event of complete fragmentation of a cometary nucleus. The observations indicate that the lower limit for the sunlit surface area of the nucleus was about 1 square kilometer before the fragmentation and that the amount of water released throughout the observing period was 3.3 × 109 kilograms. Evidence suggests that the activity of the comet was dominated by successive fragmentation. There were four major outbursts, occurring about every 16 days. The 21 July event led to the complete fragmentation and sublimation of what remained of the nucleus, producing the last 3 × 108 kilograms of water. A model where the fragment size distribution follows the power law N(R) ~ R-2.7, where N and R are the number and radius of fragments, reproduces the observed dissipation. This distribution possibly reflects the internal structure of the nucleus.

1 Finnish Meteorological Institute, Geophysics Research, Post Office Box 503, FIN-00101 Helsinki, Finland.
2 CNRS, Service d'Aéronomie, BP 3, 91371 Verrières le Buisson Cedex, France.
3 Space Physics Research Laboratory, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA.
*   To whom correspondence should be addressed. E-mail: teemu.makinen{at}fmi.fi

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
HST and VLT Investigations of the Fragments of Comet C/1999 S4 (LINEAR).
H. A. Weaver, Z. Sekanina, I. Toth, C. E. Delahodde, O. R. Hainaut, P. L. Lamy, J. M. Bauer, M. F. A'Hearn, C. Arpigny, M. R. Combi, et al. (2001)
Science 292, 1329-1333
   Abstract »    Full Text »
Organic Composition of C/1999 S4 (LINEAR): A Comet Formed Near Jupiter?.
M. J. Mumma, N. Dello Russo, M. A. DiSanti, K. Magee-Sauer, R. E. Novak, S. Brittain, T. Rettig, I. S. McLean, D. C. Reuter, and L.-H. Xu (2001)
Science 292, 1334-1339
   Abstract »    Full Text »
Outgassing Behavior and Composition of Comet C/1999 S4 (LINEAR) During Its Disruption.
D. Bockelée-Morvan, N. Biver, R. Moreno, P. Colom, J. Crovisier, E. Gérard, F. Henry, D. C. Lis, H. Matthews, H. A. Weaver, et al. (2001)
Science 292, 1339-1343
   Abstract »    Full Text »
Imaging and Photometry of Comet C/1999 S4 (LINEAR) Before Perihelion and After Breakup.
T. L. Farnham, D. G. Schleicher, L. M. Woodney, P. V. Birch, C. A. Eberhardy, and L. Levy (2001)
Science 292, 1348-1353
   Abstract »    Full Text »


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