INFRARED SPACE INTERFEROMETRY: ASTROPHYSICS & THE STUDY OF EARTH-LIKE PLANETS

ASTROPHYSICS AND SPACE SCIENCE LIBRARY

VOLUME 215

Executive Committee w. B. BURTON, Sterrewacht, Leiden, The Netherlands

J. M. E. KUIJPERS, Faculty of Science, Nijmegen, The Netherlands E. P. J. V AN DEN HEUVEL, Astronomical Institute, University of Amsterdam,

The Netherlands H. VANDER LAAN, Astronomical Institute, University of Utrecht,

The Netherlands

Editorial Board I. APPENZELLER, Landessternwarte Heidelberg-Konigstuhl, Germany

J. N. BAHCALL, The Institute for Advanced Study, Princeton, U.SA. F. BERTOLA, Universita di Padova, Italy

W. B. BURTON, Sterrewacht, Leiden, The Netherlands J. P. CASSINELLI, University of Wisconsin, Madison, U.S.A.

C. J. CESARSKY, Centre d'Etudes de Saclay, Gif-sur-Yvette Cedex, France o. ENGVOLD, Institute of Theoretical Astrophysics, University of Oslo, Norway

J. M. E. KUIJPERS, Faculty of Science, Nijmegen, The Netherlands R. McCRAY, University of Colorado, JILA, Boulder, U.S.A.

P. G. MURDIN, Royal Greenwich Observatory, Cambridge, U.K. F. PACINI, Istituto Astronomia Arcetri, Firenze, Italy

V. RADHAKRISHNAN, Raman Research Institute, Bangalore, India F. H. SHU, University of California, Berkeley, U.S.A.

B. V. SOMOV, Astronomical Institute, Moscow State University, Russia R. A. SUNY AEV, Space Research Institute, Moscow, Russia

S. TREMAINE, CITA, University of Toronto, Canada Y. TANAKA, Institute of Space & Astronautical Science, Kanagawa, Japan

E. P. J. V AN DEN HEUVEL, Astronomical Institute, University of Amsterdam, The Netherlands

H. VANDER LAAN, Astronomical Institute, University of Utrecht, The Netherlands

N. O. WEISS, University of Cambridge, U.K.

INFRARED SPACE INTERFEROMETRY:

ASTROPHYSICS & THE STUDY OF EARTH-LIKE PLANETS

Proceedings of a Workshop held in Toledo, Spain, March 11-14, 1996

Edited by

C.EIROA Universidtul Aut6noma de Madrid, Spain

A.ALBERD1 JTl.Jtituto de Astrojlsica de Andaluda, eSIC, GranatkJ, Spain

and Laboratorio de Astrojlsica Espaciaf y Fisica Fundamental, INTA, Madrid, Spain

H. TIlRONSON NASA Headquarters, Washington D.C., U.SA.

and University ojWyoming, Physics Departmem. Laramie, Wyoming, USA.

T.DEGRAAUW Space Research Organisation Netherlands. Groningen, The NetherIo.nds

and

C. J. SCHALINSKI Institute 0/ Space Sensor Techrwfogy, DLR, Berlin, Germany

SPRINGER SCIENCE+BUSINESS MEDIA, B.V.

A C.I.P. Catalogue record for this book is available from the Library of Congress

ISBN 978-94-010-6300-5 ISBN 978-94-011-5468-0 (eBook) DOI 10.1007/978-94-011-5468-0

Printed on acid-free paper

All Rights Reserved © 1997 Springer Science+Business Media Dordrecht

Originally published by Kluwer Academic Publishers in 1997 Softcover reprint of the hardcover 1 st edition 1997

No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical,

including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner.

TABLE OF CONTENTS

1. Scientific Case

A.P. BOSS - The formation of planetary systems (invited) 3

S.K. DUNKIN, M.J. BARLOW and S.G. RYAN - High resolution spec­troscopy of Vega-like stars 9

T. ENCRENAZ - Infrared observations of planetary atmospheres (invited) 13

R FERLET - Detection of planets via microlensing (invited) 25

O. FISCHER and W. PFAU - Detection of planetary spectral features through circumstellar dust: a montecarlo simulation 31

T. GUILLOT, M.S. MARLEY, D. SAUMON .and RS. FREEDMAN -Evolution and spectra of extrasolar giant planets (invited) 37

A. LEGER - Life signatures on exoplanets (invited) 47

R LISEAU and P. ARTYMOWICZ - Molecular gas production in the fJ-Pictoris disk 55

E.L. MARTIN, H. DEEG, M. CHEVRETON, J. SCHNEIDER, L. DOYLE, J. JENKINS, E. PALAIOLOGOU and W. LEE - Planets in CM-Draconis: a multi-site photometric search 59

M. MAYOR and D. QUELOZ - Epicurus was right: other worlds exist! (invited) 63

B. MENNESSON - Array configurations to detect and characterize extrasolar planets with a space infrared interferometer 71

A. NATTA and H. BUTNER - Resolving disks in YSOs (invited) 77

F. PARESCE - Ground-based optical/IR long baseline interferometry (invited) 85

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A. QUIRRENBACH - Infrared interferometry with the VLTI 97

A. QUIRRENBACH and A. ECKART - Imaging with a space-based infrared interferometer (invited) 101

G.M. VOlT - Infrared interferometry of active galaxies (invited) 109

C. WAELKENS and L.B.F.M. WATERS - Dusty disks around main sequence stars (invited) 119

D. DE WINTER, C.A. GRADY, M.R PEREZ, M.E. VAN DEN ANCK­ER, P.S. THE and A.N. ROSTOPCHINA - Comet-like bodies around the Herbig Ae star BF Ori 129

D.H. WOODEN - Stellar death: ejecta and circumstellar (invited)

2. Instrumental and Technical Cases

matter 133

P.Y. BELY - Kilometric baseline space interferometry (invited) 149

RP. BLAKE and B.W. JONES - The measurement of directional radiative properties with applications to passively cooled space telescopes 157

K. BRIESS, C.J. SCHALINSKI, H.P. ROSER and I. WALTER­Concepts for a precursor space interferometry mission with a microsatellite 163

O.CITTERIO and G. PARODI - Light weight SiC foamed mirror for telescope to be operated in space 169

D.R COULTER and S.A. MACENKA - Recent advances in cryogenic optics technology for space infrared telescope and interferometer sys­tems (invited) 173

J. GAY, Y. RABBIA and C. MANGHINI - Interfero-coronagraphy using pupil 7l"-rotation 187

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A. GLINDEMANN, S. BECKWITH, H. JOERCK, C.J. SCHALINSKI, S. ROSER and E. SCHILBACH - ASIX: the ASTRO-SPAS interfer­ometer experiment 191

T.G. HAWARDEN - Passive cooling of infrared interferometers in space (invited) 195

U. JOHANN, K. DANZMANN, C.J. SCHALINSKI and R. SESSEL­MANN - FLITE: free-flyer laser interferometer technology exper­iment 205

C. MACCONE - Advances in satellite data compression and noise­filtering by virtue of parallel computing 213

J.M. MARIOTTI - Design of infrared space (invited)

interferometers 219

J. MATHER - The next generation space telescope (NGST) 227

G. PERRIN, V. COUDE DU FORESTO, J.-M. MARIOTTI, S.T. RIDGWAY, N.P. CARLETON and W.TRAUB - High accuracy optical visibilities on long baselines: first results and prospects 233

J. ROGERS - The COAST project (invited) 241

D.G. SANDLER - Prospects for direct (invited)

imaging from the ground 247

F. SCARAMUZZI - Active cooling systems (invited) 255

M. SHAO, S. UNWIN, A. BODEN, D. VAN BUREN and S. KULKA­RNI - Space interferometry mission (invited) 267

H. SHIBAI - The infrared imaging surveyor (IRIS) project 279

N.J. WOOLF - Planet finder options II (invited) 283

N.J. WOOLF, J.R.P. ANGEL and J.M. BURGE - Planet finder options III (invited) 295

T. DE GRAAUW - Workshop Summary (invited) 309

Vlll

Subject Index

Object Index

Author Index

315

319

321

FOREWORD

The past year has produced some of the most exciting results in the history of astronomy, particularly in the area of planets outside our solar system. Only a half-year before our meeting in Toledo, Spain, the first unambiguous detection of planet-sized masses orbiting main sequence stars were reported. Since that time, evidence for a new exo­planet has been reported almost at the rate of about once per month. Some of these objects are likely to turn out to be very low-mass stars, but something like half show characteristics - Jupiter-like mass and near-zero orbital eccentricity - which appear to be unique to planets.

Almost at the same time that giant planets were being discovered regularly, the two major space agencies, ESA and NASA, have iden­tified searches for and detailed study of Earth-like planets as a major priority for the future. In ESA's "Horizon 2000 Plus" programme, an infrared interferometer has been proposed as a possible future Cor­nerstone mission. Similarly, scientists in the US produced the "Road Map for the Exploration of Neighboring Planetary Systems (ExNPS)", which provided NASA with a long-term plan which leads also to an infrared interferometer in space to study hypothetical Earth-like worlds beyond our Solar System. Such an observatory is designed to search for the thermal emission from a family of planets, using interferometric nulling to remove the contaminating light from the central star. The residual planetary light would be analyzed for the telltale signatures of molecules of water, carbon dioxide, and ozone. The presence of such molecules would be strong evidence for life on the planet.

The search for planets outside the Solar System is important also to the average citizen, who supports scientific exploration through taxes. All the participants at this meeting have had the experience of speaking with interested schoolchildren, of being stopped in buses or subways, or talking with a stranger in a long airline trip when the subject of astronomy comes up. In addition to the usual topics of black holes and quasars, over the past year our fellow citizens have become increasingly fascinated by the possibility of finding other worlds ... and other life .. . beyond the Earth. Over the centuries, scientists have had to respond our curious fellow citizens by merely stating that perhaps there are other worlds around other stars, but we just did not know for sure. For the first time in human history, scientists and technologists are now able to say, "Yes, there are planets beyond the Solar System." More

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than that, as described at this conference, we might also be able to determine whether or not those distant worlds are inhabited.

This international conference originated during a small workshop on interferometry and planet detection in Paris in the spring of 1995. More elaborate planning was undertaken at a larger workshop hosted by the German Aerospace Research Establishment (DLR) in Berlin, in September, 1995. At that time, it was becoming clear that detection of planets outside the solar system was poised to become more than a theoretical exercise: new instruments, new techniques, and new facil­ities were going to turn one of the great mysteries of humanity into an area of active scientific research, solidly grounded in observation­al data. As part of our early discussion about this conference, it was clearly desirable that the first major European meeting on the direct detection of exo-planets be held at a unique location, perhaps reflecting the new scientific discipline that is just beginning. Toledo, Spain, with its cultural and historical traditions seemed ideal.

In Europe, we received support from ESA and we are grateful to the efforts by Dr Sergio Volonte. This meeting was supported in the US by NASA's Office of Space Science and by the University of Wyoming. We are grateful to Dr Michael Bicay at NASA Headquarters and to Dr Lee Schick at the University of Wyoming for their support. In Spain, many institutions recognized the importance of this meeting. We deeply appreciate the support provided by the Universidad Autonoma de Madrid, Sociedad Espanola de Astronomia, Consejo Superior de Investigaciones Cientificas, Instituto Nacional de Tecnica Aeroespacial and Comision Interministerial de Ciencia y Tecnologia. We are also grateful to Prof. Enric Banda, the Spanish State Secretary of Univer­sities and Research, for his kind and warm welcome to all participants at the Toledo Conference.

The Editors (C. Eiroa, A. Alberdi, H. Thronson, T. de Graauw, C.J. Schalinski)

Scientific Advisory Committee: R. Angel, S. Beckwith, C. Eiroa, T. Encrenaz, T. Fukushima, T. de Graauw, A. Leger, J.M. Marcaide, J.M. Mariotti, A. Penny, R. Rodrigo, C.J. Schalinski, M. Shao, H. Thronson (Chairman), S. Volonte

Local Organizing Committee: A. Alberdi, C. Eiroa (Chairman), M. Gui­tart (Secretary), B. Montesinos, H. Thronson

UAM-LAEFF-IAA Workshop on

INFRARED SPACE INTERFEROMETRY WORKSHOP Astrophysics & the Study of Earth-like Planets

11-14 March 1996 Toledo, Spain

Participants:

1. Afonso, Jose, University of Lisbon -Physics Department- (Lisbon, Portugal)

2. Alberdi, Antxon, Instituto de Astrofisica de Andalucia (Granada, Spain); Laboratorio de Astrofisica Espacial y Fisica Fundamental-INTA- (Madrid, Spain) e-mail: alberdi@laeff.esa.es

3. Anselmi, Alberto, Alenia Spazio (Torino, Italy), e-mail: aanselmi@to.alespazio.it

4. Auh, Byung-Ryul, Korea Astronomy Observatory (Taejeon, Korea)

5. Bachem, Eberhard, German Space Agency (DARA) (Bonn, Germany)

6. Beichman, C, Jet Propulsion Laboratory (Pasadena, California, U.S.A.), e-mail: chas@ipac.caltech.edu

7. Bely, Pierre, Space Telescope Science Institute (Baltimore, Maryland, U.S.A.), e-mail: bely@stsci.edu

8. Blake, Rob, The Open University-Department of Physics- (Milton Keynes, United Kingdom), e-mail: R.P.Blake@open.ac.uk

9. Boss, Alan, Carnegie Institution of Washington (Washington DC, U.S.A.), e-mail: boss@dtm.ciw.edu

10. Briess, Klaus, Institute of Space Sensor Technology -DLR- (Berlin, Germany), e-mail: klaus@asterix.ws.ba.dlr.de

11. Casertano, Stefano, Space Telescope Science Institute (Baltimore, Maryland, U.S.A.), e-mail: stefano@stsci.edu

12. Castro-Tirado, Alberto, Laboratorio de Astrofisica Espacial y Fisica Fundamental -INTA­(Madrid, Spain), e-mail: ajct@laeff.esa.es

13. Claes, Peter, European Space Agency-Villafranca Satellite Tracking Station (Madrid, Spain), e-mail: pclaes@iso.vilspa.esa.es

14. Coude du Foresto, Vincent, Max Planck Institut fill Astronomie (Heidelberg, Germany), e-mail: foresto@mpia-hd.mpg.de

15. Coulter, Dan, Jet Propulsion Laboratory (Pasadena, California, U.S.A.), e-mail: daniel.r.coulter@jpl.nasa.gov

16. de Graauw, T, Space Research Organisation Netherlands (Groningen, The Netherlands), e-mail: thijsdg@sron.rug.nl

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17. de Korte, Pieter, Space Research Organisation Netherlands (Utrecht, The Netherlands), e-mail: P.deKorte@sron.rug.nl

18. de Winter, Dolf, Universidad Autonoma de Madrid (Madrid, Spain), e-mail: dolf@astro.uva.nl

19. Dunkin, Sarah D., Department of Physics and Astronomy, University College London (Lon­don, England), e-mail: skd@starlink.ucl.ac.uk

20. Eiroa, Carlos, Universidad Autonoma de Madrid (Madrid, Spain), e-mail: carlos@astroi.ft.uam.es

21. Encrenaz, Therese, Observatoire de Paris (Meudon, France), e-mail: tencrenaz@mesioa.obspm.fr

22. Faucherre, Michel, GRAALjCNRS, Universite de Montpellier II (Montpellier, France), e-mail: faucherr@graal.univ-montp2.fr

23. Ferlet, Roger, Institut d'Astrophysique (Paris, France), e-mail: ferlet@iap.fr

24. Festou, Michel, Observatoire Midi-Pyrenees (Toulouse, France), e-mail: festou@obs-mip.fr

25. Figueras, Francesca, University of Barcelona-Dept. of Astronomy & Meteorology- (Barcelona, Spain), e-mail: cesca@mizar.am.ub.es

26. Fischer, Olaf, Universitats Sternwarte-Astrophysikalisches Institut- (Jena, Germany), e-mail: fischer@betty.astro.uni-jena.de

27. Fontana, Walter, University of Wien, Institute for Theoretical Chemistry (Wien, Austria), e-mail: walter@stat.umn.edu

28. Garzon, Francisco, Instituto de Astrofisica de Canarias (Tenerife, Spain), e-mail: fgl@iac.es

29. Gautier, Daniel, Observatoire de Paris -DESPA- (Meudon, France), e-mail: daniel.gautier@obspm.fr

30. Gilbreath, Charmaine, US Naval Research Laboratory (Washington DC, U.S.A.), e-mail: gilbreath@ncst.nrl.navy.mil

31. Gimenez, Alvaro, Instituto Nacional de Tecnica Aeroespacial (Torrejon de Ardoz, Madrid), e-mail: ag@laeff.esa.es

32. Glindemann, Andreas, Max Planck Institut fiir Astronomie (Heidelberg, Germany), e-mail: glindem@mpia-hd.mpg.de

33. Goldsmith, Donald, Interstellar Media (Berkeley, California, U.S.A.), e-mail: dgoldsmith@astron.berkeley.edu

34. Gomez, Jose Francisco, Laboratorio de Astroffsica Espacial y Fisica Fundamental -INTA­(Madrid, Spain), e-mail: jfg@laeff.esa.es

35. Greenaway, Alan, ORA Malvern (Malvern, United Kingdom), e-mail: ahg%ccf.dnet@hermes.dra.hmg.gb

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36. Guillot, Tristan, University of Arizona -Lunar and Planetary Laboratory- (Tucson, Arizona, U.S.A.), e-mail: guillot@lpl.arizona.edu

37. Harris, Alan, DLR Institute for Planetary Exploration (Berlin, Germany), e-mail: harris@terra.pe.ba.dlr.de

38. Hawarden, Timothy G, Joint Astronomy Centre (Hilo, Hawaii, U.S.A.), e-mail: hawarden@jach.hawaii.edu

39. Huygen, Eric, Katholieke Universiteit Leuven -Instituut Sterrenkunde- (Heverlee, Belgium), e-mail: rik@ster.kuleuven.ac.uk

40. Johann, Ulrich, Dornier SatellitenSysteme GmbH (Friedrichshafen, Germany), e-mail: johann@eosys.dofn.de

41. Jones, Barrie William, The Open University-Department of Physics- (Milton Keynes, United Kingdom), e-mail: b.w.jones@open.ac.uk

42. Joubert, Martine, CNES, (Paris, France), e-mail: joubert@cst.cnes.fr

43. Kaplan, Michael, NASA Headquarters (Washington DC, U.S.A.), e-mail: mskaplan@gm.ossa.hq.nasa.gov

44. Kessler, Martin, European Space Agency-Villafranca Satellite Tracking Station (Madrid, Spain), e-mail: mkessler@iso.vilspa.esa.es

45. Laskin, Robert, Jet Propulsion Laboratory -CaITech- (Pasadena, California, U.S.A.), e-mail: bob-laskin@343mac.jpl.nasa.gov

46. Leger, Alain, Universite Paris-Sud -IAS- (Orsay, France), e-mail: leger@iaslab.ias.fr

47. Lena, Pierre, Observatoire, Univ. Paris VII (Paris, France), e-mail: lena@obspm.fr

48. Liseau, Rene, Stockholm Observatory (Saltsjobaden, Sweden), e-mail: rene@astro.su.se

49. Lund, Glenn, Aeroespatiale -Centre Operationnel Satellites (Cannes La Bocca, France)

50. Luri, Xavier, University of Barcelona-Dept. of Astronomy & Meteorology- (Barcelona, Spain), e-mail: xavier@mizar.am.ub.es

51. Malfait, Koen, Katholieke Universiteit Leuven, Instituut Sterrenkunde (Heverlee, Belgium), e-mail: koenm@ster.kuleuven.ac.be

52. Mampaso, Antonio, Instituto de Astrofisica de Canarias (Tenerife, Spain), e-mail: amr@iac.es

53. Marcaide, Juan Maria, Universidad de Valencia (Valencia, Spain), e-mail: jmm@vlbi.matapl.uv.es

54. Mariotti, Jean Marie, Observatoire de Paris -DESPA- (Meudon, France), e-mail: mariotti@obspm.fr

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55. Martin, Eduardo, Instituto de Astrofisica de Canarias (Tenerife, Spain), e-mail: ege~iac.es

56. Mather, John C, NASA Goddard Space Flight Center (Baltimore, Maryland, U.S.A.), e-mail: mather~stars.gsfc.nasa.gov

57. Mayor, Michel, Observatoire de Geneve (Sauverny Switzerland), e-mail: mayor~scsun.unige.ch

58. Mennesson, Bertrand, University of Arizona -Steward Observatory- (Tucson, Arizona, U.S.A.), e-mail: bmenness~as.arizona.edu

59. Moitinho de Almeida, Andre, Instituto de Astrofisica de Andalucia (Granada, Spain), e-mail: andre~iaa.es

60. Montesinos, Benjamin, Instituto de Astrofisica de Andalucia (Granada, Spain); Laboratorio de Astrofisica Espacial y Fisica Fundamental-INTA- (Madrid, Spain), e-mail: bmm@laeff.esa.es

61. Moreira, Miguel, University of Lisbon -Physics Department- (Lisbon, Portugal)

62. Mundt, Reinhard, Max Planck Institute fiir Astronomie (Heidelberg, Germany), e-mail: mundt@mpia-hd.mpg.de

63. Natta, Antonella, Osservatorio di Arcetri (Firenze, Italy), e-mail: natta@arcetri.astro.it

64. Oro, Juan, University of Houston-Dept. of Biochemical & Biophysical Sciences (Houston, Texas, U.S.A.)

65. Pain, Thierry, Aeroespatiale -Centre Operationnel Satellites (Cannes La Bocca, France)

66. Paresce, Francesco, European Southern Observatory (Garching bei Munchen, Germany) e-mail: fparesce@eso.org

67. Parodi, GianCarlo, BCV Progetti (Milano, Italy), e-mail: gian@bcv.sublink.org

68. Penny, Alan, Rutherford Appleton Laboratory (Oxon, United Kingdom), e-mail: ajp@ast.star.rl.ac.uk

69. Perrin, Guy, Observatoire de Paris-Meudon (Meudon, France), e-mail: perrin@hplyot.obspm.fr

70. Petro, Larry, Space Telescope Science Institute (Baltimore, Maryland, U.S.A.) e-mail: petro@stsci.edu

71. Pina, Robert, University of Florida -Dept. of Astronomy- (Gainesville, Florida, U.S.A.), e-mail: rpina@astro.ufl.edu

72. Quirrenbach, Andreas, Max Planck Institute fiir Extraterrestrische Physik (Garching, Ger­many), e-mail: quirrenbach@mpe-garching.mpg.de

73. Rabbia, Yves, O.C.A. (Grasse, France)

74. Ridgway, Stephen, Kitt Peak National Observatory (Tucson, Arizona, U.S.A.), e-mail: ridgway@noao.edu

75. Rodrigo, Rafael, Instituto de Astrofisica de Andalucia (Granada, Spain), e-mail: rodrigo@iaa.es

76. Rodriguez Espinosa, J.M., Instituto de Astrofisica de Canarias (Tenerife, Spain), e-mail: jre@ll.iac.es

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77. Rogers, John, Cambridge University -Radio Astronomy Department- (Cambridge, United Kingdom), e-mail: john@mrao.cam.ac.uk

78. Rouan, Daniel, Observatoire de Paris-Meudon (Meudon, France), e-mail: rouan@obspm.fr

79. Rowan-Robinson, M, Astrophysics Group, Blackett Lab., Imperial College (London, Eng­land), e-mail; mrr@ic.ac.uk

80. Sandler, David, University of Arizona & ThermoTrex Corp. (San Diego, California, U.S.A.), e-mail: dsandler@cts.com

81. Saraceno, Paolo, Istituto di Fisica dello Spazio Interplanetario -CNR- (Frascati, Italy), e-mail: saraceno@ifsi.fra.cnr.it

82. Scaramuzzi, Franco, Istituto di Astrofisica Spaziale (Frascati, Italy) e-mail: scaramuzzi%efr419@frascati.enea.it

83. Schalinski, Cornelius J., Institute of Space Sensor Technology -DLR- (Berlin, Germany), e-mail: schalinski@dlr.de

84. Schneider, Jean, Observatoire de Paris (Meudon, France), e-mail: schneider@obspm.fr

85. Schilling, Govert, Free-Lance Science Writer (Utrecht, The Netherlands) e-mail: goverts@knoware.nl

86. Shao, Michael, Jet Propulsion Laboratory (Pasadena, California, U.S.A.), e-mail: mShao@huey.jpl.nasa.gov

87. Shibai, Hiroshi, The Institute of Space and Astronautical Science (ISAS) (Kanagawa, Japan), e-mail: shibai@astro.isas.ac.jp

88. Simeoni, Denis, Aeroespatiale -Centre Operationnel Satellites (Cannes La Bocca, France)

89. Simon, Richard, National Radio Astronomy Observatory (Charlottesville, Virginia, U.S.A.), e-mail: rsimon@nrao.edu

90. Stanton, Richard, Jet Propulsion Laboratory -Caltech- (Pasadena, California, U.S.A.), e-mail: r.stanton@jpl.nasa.gov

91. Telesco, Charles, University of Florida -Dept. of Astronomy- (Gainesville, Florida, U.S.A.), e-mail: telesco@astro.ufl.edu

92. Thronson, Harley, University of Wyoming-Physics Department- (Laramie, Wyoming, U.S.A.); NASA Headquarters (Washington D.C., U.S.A.), e-mail: Harley.Thronson@hq.nasa.gov

93. Torra, Jordi, University of Barcelona -Dept. of Astronomy & Meteorology- (Barcelona, Spain), e-mail: jordi@mizar.am.ub.es

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94. Tytler, David, University of California - San Diego, (La Jolla, California, USA)

95. Vazquez, Roberto, Instituto de Astrofisica de Andalucfa (Granada, Spain), e-mail: vazquez@iaa.es

96. Voit, Mark, Space Telescope Science Institute (Baltimore, Maryland, U.S.A.), e-mail: voit@stsci.edu

97. Volonte, Sergio, European Space Agency -Headquarters- (Paris, France), e-mail: svolonte%esa.bitnet@listserv.gmd.de

98. Waelkens, Christoffel, Institut voor Sterrenkunde (Leuven, Belgium), e-mail: christoffel@ster.kuleuven.ac.be

99. Walmsley, Malcolm, Osservatorio di Arcetri (Firenze, Italy), e-mail: walmsley@arcetri.astro.it

100. Waters, Rens, University of Amsterdam -Astronomical Institute- (Amsterdam, The Nether­lands), e-mail: rensw@astro.uva.nl

101. Wesselius, Paul R., SRON (Groningen, The Netherlands), e-mail: p.r.wesselius@sron.rug.nl

102. Wooden, Diane, NASA Ames Research Center (Moffett Field, California, U.S.A.), e-mail: wooden@ssal.arc.nasa.gov

103. Woolf, Neville, University of Arizona -Steward Observatory (Tucson, Arizona, U.S.A.), e-mail: nwoolf@as.arizona.edu

104. Yanagisawa, Masahisa, University of Electro-Communications (Tokyo, Japan) e-mail: yanagi@alfven.ee.uec.ac.jp

105. Yun, Joao, University of Lisbon -Physics Department- (Lisbon, Portugal), e-mail: yun@astro.cc.fc.ul.pt