NASA Conference Publication 3343 From Stardust to Planetesimals: Contributed Papers Edited by M. E. Kress, A. G. G. M. Tielens, and Y. J. Pendleton RIL2827 LYF)RARY 15 06r RG AT3, CA 934-37-5223 Proceedings of a symposium held in Santa Clara, California June 24-26, 1996 NASA Conference Publication 3343 From Stardust to Planetesimals: Contributed Papers Edited by M. E. Kress, A. G. G. M. Tielens, and Y. J. Pendleton Ames Research Center, Moffett Field, California Proceedings of a symposium held in Santa Clara, California June 24 26, 1996 ^ a ^ National Aeronautics and Space Administration Ames Research Center Moffett Field, California 94035-1000 1996 PREFACE On June 24 through 26, 1996, a scientific conference entitled From Stardust to Planetesimals was held at the Westin Hotel, Santa Clara, California, as part of the 108th annual meeting of the Astronomical Society of the Pacific. This conference was made possible by generous grants from the Astrophysics and Exobiology programs of the National Aeronautics and Space Administration, and support services rendered by the dedicated staffs of NASA Ames Research Center and the Astronomical Society of the Pacific. Over the last decade, our understanding of the formation and early evolution of the solar System has advanced considerably due to progress that has been made simultaneously on many fronts. Stardust has been isolated in meteorites and interplanetary dust particles (IDPs), providing us with sample materials which predate the solar system and which offer clues to the processing that has occurred. At the same time, infrared studies have led to a better characterization of the composition of interstellar dust, which is now readily accepted as an important component of the interstellar medium. Infrared observations have also provided a much better view of the star-formation process and the role of dust therein. Recently, the presence of Kuiper Belt planetesimals has been confirmed and spectroscopy of these rather pristine objects may soon become available. Analysis of spacecraft data from the Comet Halley flybys has yielded a wealth of information on the composition of this comet. These observational advances have changed our understanding of planetesimal processing. The launch of the Infrared Space Observatory, the opening of 10-meter class telescopes, and, in the longer term, the Rosetta mission, promise to continue to broaden and deepen our understanding of the evolution from stardust to planetesimals. For these reasons we considered it timely to organize a meeting focused on the processes that connect stardust and planetesimals. The goal of this meeting was, therefore, to bring together astronomers interested in star- and planet-formation, planetary scientists studying early solar system relics, laboratory scientists studying the processing of analogs, and scientists analyzing meteorites and interplanetary dust particles, grain by grain. As a result of this endeavor, over 200 participants, including 153 scientists from 14 different countries, gathered to discuss the origin and evolution of stardust. We hope that this encounter in Santa Clara will foster an ongoing interchange of information and ideas within this diverse group of scientists. A major aim of this meeting was to produce conference proceedings which reflect the current situation regarding the evolution from stardust to planetesimals. This volume contains the contributed papers presented at the meeting. The invited review papers will be published separately in the Astronomical Society of the Pacific conference series. We extend special thanks to Greg Sloan, who produced the poster paper abstract book which was a tremendous asset during the meeting. The conference was dedicated to three outstanding scientists whose untimely deaths left many hearts saddened. James Pollack, Akira Sakata, and Jason Cardelli each contributed significantly to the body of knowledge presented at this conference. Their scientific insight will be missed as we continue to explore the pathway From Stardust to Planetesimals. Tributes to their scientific achievements can be found in the proceedings book of the invited review papers. We thank the Local and Scientific Organizing Committees, NASA Ames Research Center, and the Astronomical Society of the Pacific for making this conference a rewarding endeavor. M. E. Kress A. G. G. M. Tielens Y. J. Pendleton Moffett Field, CA November, 1996 SCIENTIFIC ORGANIZING COMMITTEE P. Bodenheimer (University of California, Santa Cruz) Alan Boss (Carnegie Institute, Washington) Don Brownlee (University of Washington, Seattle) John Kezridge (University of California, San Diego) Michael Mumma (Goddard Space Flight Center) Jane Luu (Harvard University, Boston) Tobias Owen (University of Hawaii, Honolulu) Yvonne Pendleton (NASA Ames Research Center, Chair) T.P. Snow (Univeriity of Colorado, Boulder) A.G.G.M. Tielens (NASA Ames Research Center) LOCAL ORGANIZING COMMITTEE Max Bernstein Maureen Savage Steven Charnley Jeff Scargle Michael Kaufman Greg Sloan Monika Kress Dave Scimeca Bill Latter. Bob Walker Brent Rogerville Juliet Wiesema Scott Sandford Sue Zabor iv TABLE OF CONTENTS page Preface.................................................................................. m Scientific and Local Organizing Committees ....................................... iv 5 PIC AND SIMILAR DISK-LIKE OBJECTS Planetesimals around V536 AQL ................................................... 3 N. Ageorges & W.J. Duschl Modelling the dust around Vega-like stars ......................................... 9 R.J. Sylvester, C.J. Skinner & M.J. Barlow Examples of comet-like spectra among P Pic-like stars .......................... 13 H.M. Butner, H.J. Walker, D.H. Wooden & F.C. Witteborn Partially crystalline silicate dust in protostellar disks ............................. 19 M.L. Sitko, D.K. Lynch, R.W. Russell, M.S. Hanner & C.A. Grady High-resolution spectroscopy of Vega-like stars: abundances and circumstellar gas ....................................................................... 23 S.K. Dunkin, M.J. Barlow & S.G. Ryan Transient accretion events in Herbig Ae/Be star spectra: the evidence for infalling planetesimals in HD 100546 (B9e) ....................................... 27 C.A. Grady, M.R. Perez & K.S. Bjorkman STAR FORMATION The remarkable Herbig Ae star V351 Ori .......................................... 33 M.E. van den Ancker, P.S. The & D. de Winter Dust around Herbig Ae stars: additional constraints from their photometric and polarimetric variability ........................................................... 37 N.A. Krivova, V.B. Il'in & O. Fischer An infrared study of the juggler nebula .............................................. 41 J. C. Holbrook, P. Temi, D. Rank & J. Bregman Imaging polarized dust emission in star formation regions with the OVRO mm array..................................................................................... 45 R. Akeson & J. Carlstrom V The spectral energy distribution of HH 100 IRS ................................. 49 R. Siebenmorgen Externally induced evaporation of young stellar disks in Orion ................. 55 D. Johnstone, D. Hollenbach & F. Shu CIRCUMSTELLAR DUST The 11 µm silicon carbide feature in carbon star shells ........................... 61 A.K. Speck, M.J. Barlow & C.J. Skinner On the classification of infrared spectra from circumstellar dust shells ......... 65 G.C. Sloan, I.R. Little-Marenin & S.D. Price Formation of cosmic carbon dust analogs in partially hydrogenated atmospheres ............................................................................ 69 A. Blanco, S. Fonti, A.M. Muci & V Orofino Time dependent models of grain formation around carbon stars ................ 73 M.P. Egan & R.F. Shipman The size distribution of stardust injected into the ISM ........................... 77 D. Kruger & E. Sedlmayer Constraints on circumstellar dust grain sizes from high spatial resolution observations in the thermal infrared ................................................. 81 E.E. Bloemhof, R.M. Danen & C.R. Gwinn INTERSTELLAR DUST Revised depletions and new constraints on interstellar dust composition ...... 87 T.P. Snow & A.N. Witt 0 The interstellar polarization feature associated with the 2175 A extinction bump .................................................................................... 93 G.C. Clayton, M.J. Wolff, S.H. Kim, P.G. Martin & C.M. Anderson Interstellar extinction, polarization, and grain alignment in high-latitude clouds 97 K.A. Larson & D.C.B. Whittet The extinction properties of heavily-reddened lines of sight in the Galaxy .... 101 M.G. Rawlings, A.J. Adamson & D.C.B. Whittet HAC: band gap, photoluminescence, and optical/near-infrared absorption .... 105 A.N. Witt, D. Ryutov & D.G. Furton vi The role of hydrogen in small amorphous carbon grains: the IR spectrum .... 109 V. Mennella, L. Colangeli, C. Cecchi Pestellini, E. Palomba, P Palumbo, A. Rotundi & E. Bussoletti Observations of two nonstandard grain components ............................. 113 R.F. Shipman, S.J. Carey & F.O. Clark IRAS colors of the Pleiades .......................................................... 117 S.J. Carey, R.F. Shipman & F.O. Clark PAH emission in the Orion Bar ..................................................... 121 J. Bregman & G.C. Sloan Laboratory experiments on the reactions of PAH cations with molecules and atoms of interstellar interest .......................................................... 125 V. LePage, H.S. Lee, V.M. Bierbaum & T.P.