553_ WORKSHOP ON Analysis of Returned Comet Nucleus Samples JANUARY 16-18, 1989 MILPITAS, CALIFORNIA SPONSORED BY LUNAR AND PLANETARY INSTITUTE NASA AMES RESEARCH CENTER N90-i6O07 (NASA-CR-18482I) WO&KSH0P ON ANALY _-[S (_F --[HRU-- _FTtJ_NED CuMET NUCLEUS SAMPLES (lunar and N90-I6O56 Planetory Inst.) 98 P CSCL 039 unclas Ga/_o 0217530 f Papers Presented to the Workshop on Analysis of Returned Comet Nucleus Samples Milpitas, California January16-18,1989 Sponsored by Lunar and Planetary Institute NASA Ames Research Center LPI Contribution No. 691 Material in this volume may be copied without restraint for library, abstract service, educational, or research purposes; however, republication of any paper or portion thereof requires written permission from the author as well as appropriate acknowledgment of this publication. Cover photo courtesy of H. U. Keller. Copyright hem by Max-Planck-lnstitut fur Aeronomie, Lindau- Katlenbur_ FRG. Available from the Lunar and Planetary Institute as part of the Comet Halley image sequence (#C3443). Preface This volume contains abstracts that have been accepted by the Program Committee for presentation at the Workshop on Analysis of Returned Comet Nucleus Samples, held in Milpitas, California, January 16-18, 1989. Conveners are Sherwood Chang (NASA Ames Research Center) and Larry Nyquist (NASA Johnson Space Center). Program Committee members are Thomas Ahrens (ex-officio, California Institute of Technology), Lou Allamandola (NASA Ames Research Center), David Blake (NASA Ames Research Center), Donald Brownlee (University of Washington, Seattle), Theodore E. Bunch (NASA Ames Research Center), Humberto Campins (Planetary Science Institute), Jeff Cuzzi (NASA Ames Research Center), Eberhard Grun (Max-Planck-Institut fur Kernphysik), Martha Hanner (Jet Propulsion Laboratory), Alan Harris (Jet Propulsion Laboratory), John Kerridge (University of California, Los Angeles), Yves Langevin (University of Paris), Gerhard Schwehm (ESTEC), and Paul Weissman (Jet Propulsion Laboratory). Logistics and administrative support for the workshop were provided by the LPI Projects Office. This volume was prepared by the Publications Office of the Lunar and Planetary Institute, 3303 NASA Road One, Houston, Texas 77058-4399. The LPI is operated by the Universities Space Research Association under Contract No. NASW-4066 J with the National Aeronautics and Space Administration. TABLE OF CONTENTS Analytical Study of Comet Nucleus Samples A. L. Albee ......................................................................................................................... 1 The Origin, Composition and History of Cometary Ices from Spectroscopic Studies L. J. Allamandola ....................................................... ,...................................................... 3 Experimental Studies of Gas Trapping in Amorphous Ice and Thermal Modelling of Comets - Implications for Rosetta A. Bar-Nun ......................................................................................................................... 5 On the Isotope Analysis of Cometary Dust F. Begemann ...................................................................................................................... 8 Direct Determination of the Morphology, Structure and Composition of Cometary and Interstellar Ice Analogs in the Laboratory D. F. Blake and L. J. Allamandola .................................................................................. 9 Electron Beam Analysis of Particulate Cometary Material J. Bradley ............................................................................................................................. 11 Thermal and Chemical Processing of the Outermost Layer of Cometary Nuclei H. Campins and E. P. Krider ............................................................................................ 12 The Carbon Chemistry of Meteorites: Relationships to Comets S. Chang .............................................................................................................................. 13 Laboratory Analyses of Micron-sized Solid Grains: Experimental Techniques and Recent Results L. Colangeli, E. Bussoletti, A. Blanco, A. Borghesi, S. Fonti, I_. Orofino, and G. Schwehm ........................................................................................... 15 Analysis of Organic Compounds in Returned Comet Nucleus Samples .I.R. Cronin ........................................................................................................................ 16 Non-Equilibrium Chemistry in the Solar Nebula and Early Solar System: Implications for the Chemistry of Comets B. Fegley, Jr. ....................................................................................................................... 18 Trace Element Abundance Determinations by SynchrotronX-ray Fluorescence(SXRF) on Returned Comet Nucleus Mineral Grains G. J. Flynn and S. R. Sutton ............................................................................................. 20 From Interstellar Dust to Comets J. M. Greenberg .................................................................................................................. 22 Modifications of Comet Materials by the Sublimation Process: Results from Simulation Experiments E. Grun and KOSl-team ................................................................................................... 24 Comments on Comet Shapes and Aggregation Processes W. K. Hartmann ................................................................................................................. 26 Cosmogenic Nuclides in Cometary Materials: Implications for Rate of Mass l_x_ss and Exposure History G. F. Herzog, P. A. J. Englert, and R. C. Reedy .............................................................. 28 Morphology and Compositional Differentiation of the Surface of Comets W. F. Huebner and D. C. Boice ....................................................................................... 30 Role of Dust to Gas Production Rate Ratio in Cometary Physics S. lbadov ............................................................................................................................. 31 Radiation Modification of Cometary Materials: Laboratory Simulations R. 17,.Johnson ..................................................................................................................... 32 Sulfur Compounds in Comets S. Kim and M. A 'Hearn ...................................... .............................................................. 33 Organic Chemistry of Cometary Dust as Derived from PUMA 1 Data J. KisseI and F. R. Krueger ........ ,.... ,..... : ............................................................................ 35 Identification of Solar Nebula Condensateg ii_ Interplanetary Dust Particles and Unequilibrated Ordinary Chondrites W. Klock, K. L. Thomas, and D. S. McKay .................................................................... 36 Spectrophotometric Observations of Comet P/Giacobini-Zinner I. Konno, S. Wyckoff and P. A. Wehinger ...... ,............................................................... 38 Composition of Dust from Comet P/Halley: The Mineral Fraction Y.. Langevin ......................................................................................................................... 40 Computer Simulation of Dust Grain Evolution K. Liffman .......................................................................................................................... 41 Prompt Gamma Activation Analysis (PGAA): Technique of Choice for Nondestructive Bulk Analysis of Returned Comet Samples? D. J. Lindstrom and R. M. Lindstrom ............................................................................. 43 Solar Nebula Condensates and the Composition of Comets J. I. Lunine ......................................................................................................................... 45 Candidate Sample Acquisition Systems for the Rosetta Mission P. G. Magnani, C. Gerli, G. Colombina, and P. Vielmo ............................................... 47 Interstellar and Cometary Dust J. S. Mathis ......................................................................................................................... 48 The In-Situ Cometary Particulate Size Distribution Measured for One Comet: P/Halley J. A. M. McDonnell and G. S. Pankiewicz ...................................................................... 50 Evolution of Carbonaceous Chondrite Parent Bodies: Insights into Cometary Nuclei? 1t. Y. McSween, Jr. ............................................................................................................ 52 The Comet Rendezvous Asteroid Flyby Mission D. Morrison, M. Neugebauer, and P. Weissman ............................................................ 54 Measurements of Long-Lived Cosmogenic Nuclides in Returned Comet Nucleus Samples K. Nishiizumi, C. P. Kohl, and J. R. Arnold .................................................................... 56 Metamorphism of Cosmic Dust: Processing from Circumstellar Outflows to the Cometary Regolith J. A. Nuth, III .................................................................................................................... 58 Microanalytical Characterization of Biogenic Components of Interplanetary Dust F. RtMk:ati di Brozolo, G. P. Meeker, and IL H. Fleming ............................................. 59 What if Chondritic Porous Interplanetary Dust Particles Are Not the Real McCoy?