HIPPARCOS

Venice '97

Presentation of

the Hipparcos and Tycho Catalogues

and first astrophysical results

of the Hipparcos space astrometry mission

Organised and sponsored by

The European Space Agency

under the auspices of the

City of Venice

Fondazione Cini

Isola di S. GiorgioVenice, Italy

13-16 May 1997

Co-sponsored by Matra Marconi Space

(Prime Contractor for the Hipparcos satellite)

and by

AleniaSpazio

(Co-Prime Contractor for the Hipparcos spacecraft)

a Contents

Session 1: Description of the Hipparcos and Tycho Catalogues

(Chair: A. Blaauw)

The Hipparcos Catalogue Contents 1

M.A.C. Ferryman

Astrometric Properties of the Hipparcos Catalogue 5

F. Mignard

Connection of the Hipparcos Catalogue to the Extragalactic Reference Frame 11

J. Kovalevsky

The Hipparcos Catalogue Double and Multiple Systems Annex 13

L. Lindegren

The Hipparcos Photometry and Variability Annexes 19

F. van Leeuwen

The Tycho Catalogue: Astrometry and Photometry 25

E. H0g

The Tycho Catalogue: Stellar Content 31

D. Egret, C. Fabncius

The Hipparcos Solar System Objects Annexes 35

D. Hestroffer

POSTERS

Volume 13: The Atlas of Identification Charts 41

D. Megevand, P. Bartholdi, L. Weber

A Comparative Analysis of Some Statistical Properties of the Hipparcos Catalogue ....45

B. Bucciarelli

Determination of the PPN Parameter 7 with the Hipparcos Data 49

M. Froeschle, F. Mignard, F. Arenou

Hipparcos Extragalactic Link: the Potsdam Contribution 53

S. Hirte, E. Schilbach, R.-D. Scholz

Comparison of the FK5 Frame to Hipparcos 57

F. Mignard, M. Froeschle

Contribution of the Main Astronomical Observatory, Ukraine, to the Reference Frame Link 61

V.S. Kislyuk, S.P. Rybka, A.I. Yatsenko, N.V. Kharchenko, Ya.S. Yatskiv

Some Considerations in Making Full Use of the Hipparcos Catalogue 63

A.G.A. Brown, F. Arenou, F. van Leeuwen, L. Lindegren, X. Luri

Contents Hi

Session 2: Astrometric Results

(Chair: L. Lindegren)

The Hipparcos/Tycho ASCII CD-ROMs and Access Software 69

H. Schrijver

Celestia 2000 73

C. Turon, D. Priou, M.A.C. Ferryman

The Millennium Star Atlas 79

R.W. Sinnott

On-Line Services at CDS for Distribution of Hipparcos Data 81

D. Egret, F. Ochsenbein, F. Genova

CPC2 Plate Reductions with Hipparcos Stars: First Results 85

N. Zacharias, C. de Vegt, C.A. Murray

Improvement of the Orbits of Asteroids and the Mass of (1) Ceres 91

B. Viateau, M. Rapaport

The Hipparcos Catalogue: a Reference Frame for Earth Orientation in 1899.7-1992,0... 95

J. Vondrdk, C. Ron, I. Pesek, A. Cepek

POSTERS

An Algorithm for Calculating Frame Rotations and its Application to Hipparcos 101

H. Lenhardt, H.G. Walter, R. Hering

Accurate Ground-Based Parallaxes to Compare with Hipparcos 105

B.C. Harris, C.C. Dahn, D.G. Monet

Hipparcos and Ground-Based Proper Motions of NPZT Stars 109

M. Yoshizawa

Comparison between the ILS-MD and Hipparcos Catalogues 113

A. Poma, S. Uras, R. Pannunzio

Comparisons of Results from Hipparcos with Ground-Based and Radio Observations. . .

117

Xu Tongqi, Lu Peizhen, Jin Wejing

Comparing the Tycho Catalogue with CCD Astrograph Observations 121

N. Zacharias, E. Hpg, S.E. Urban, T.E. Corbin

Tycho Reference Catalogue: Pilot Project Results 125

A. Kuzmin, U. Bastian, E. H0g, K. Kuimov, S. Roser

Some First Experiments on the Photometric Calibration of Schmidt Plates against Tycho . 129

J.E. Morrison, B. Lasker, B. Mclean, B. Bucciarelli, A. Spagna, A. Zacchei

A Photometric Calibration of the Guide Star Catalog 131

C. Fabricius

CCD Meridian Circle Reductions using Tycho Positions as Reference 135

Y. Requieme, J.F. Le Campion, G. Montignac, et al.

iv Contents

First Steps to Re-Observation of the Hipparcos/Tycho Stars by Ground-Based AMCs . . .139

A. Kovalchuk, G. Pinigm, Yu. Protsyuk, A. Shulga

Future Control of the Hipparcos Frame using MERLIN 143

L.V. Morrison, S.T. Gamngton, R.W. Argyle, R.J. Davis

The Hipparcos Data and Resolving the Problems in the Northern Polar Region 147

L.G. Taff, V. Tel'nyuk-Adamchuk, 0. Molotaj

Check on JPL DExxx using Hipparcos and Tycho Observations 149

L.V. Morrison, D. Hestroffer, D.B. Taylor, F. van Leeuwen

The NPM and SPM Contributions to the Hipparcos Proper-Motion Link 153

I. Platazs, V. Kozhurina-Platais, T.M. Girard, et al.

Impact of Hipparcos Data on Astrometric Reduction of Solar System Bodies 157

A. Fienga, J.E. Arlot, D. Pascu

Astrolabe Observations of the Sun on the Hipparcos Reference Frame 161

A.H. Andrei, J.L. Penna, P. Benevides-Soares, F. Laclare

Robust Estimation with Application to Hipparcos Minor Planet Data 165

M.L. Bougeard, J.-F. Bange, C. Caqumeau, A. Bec-Borsenberger

Determination of the Masses of Minor Planets 169

J.-F. Bange, A. Bec-Borsenberger

Determination of Limb-Darkening from Hipparcos Observations 173

D. Hestroffer, F. Mignard

UCAC-S: a New High Precision, High Density Astrometric Catalogue in the S. Hemisphere 177

N. Zacharias, M.E. Germain, T.J. Rafferty

Astrometric CCD Positions for Extragalactic Radio Sources 181

M. Assafin, R. Vieira Martins, A.H. Andrei

Work on Astrometry from 1993 - 1996 at Shanghai Astronomical Observatory 185

J.L. Zhao, J.J. Wang

Using the Tycho Catalogue for AXAF 187

P.J. Green, T.A. Aldcroft, M.R. Garcia, P. Slane, J. Vrtilek

The Use of the Hipparcos and Tycho Catalogues in Flight Dynamics Operations at ESOC.

191

A. Batten, X. Marc, A. McDonald, A. Schiitz

Hipparcos as Input Catalogue for the GOMOS ENVISAT Instrument 195

G. Ratter, J.L. Bertaux, J. Langen, T. Paulsen, A. Popescu, F. Spiero

Optical Monitoring of Variable Sources from Space: the OMC onboard INTEGRAL...

199

A. Gimenez, J. Torra, J.M. Mas-Hesse, X. Lun, C. Jordi, F. Figueras, R. Asiam

Application Possibilities for the Hipparcos Intermediate Astrometric Data 203

F. van Leeuwen

Contents v

Sessions 3~4: Stellar Physics

(Chairs: M. Grenon & P.E, Nissen)

The Luminosity Calibration of the HR Diagram Revisited by Hipparcos 207A.E. Gomez, X. Luri, M.O. Mennessier, J. Torra, F. Figueras

The Luminosities and Diameters of Mira Variables from Hipparcos Parallaxes 213P.A. Whitelock, F. van Leeuwen, M.W. Feast

The HR Diagram in the Plane log(Teff), M\>0\ of Pop. II Stars with Hipparcos Parallaxes.219

R. Cayrel, Y. Lebreton, M.-N. Perrin, C. Turon

Surface Gravities of Metal-Poor Stars Derived from Hipparcos Parallaxes 225

P.E. Nissen, E. H0g, W.J. Schuster

The Age and Helium Content of the Hyades Revisited 231

Y. Lebreton, A.E. Gomez, J.C. Mermilliod, M.A.C. Perryman

Searching for Wolf-Rayet and O-Star Runaways using Hipparcos Proper Motions 237

A.F.J. Moffat, S.V. Marchenko, W. Seggewiss, et al.

Absolute Magnitudes of Chemically Peculiar Stars 239

P. North, C. Jaschek, B. Hauck, F. Figueras, J. Torra, M. Kunzli

Evolutive Stage of the Am-type stars 245

B. Nicolet

Binary Star Masses from Hipparcos 251

S. Soderhjelm, L. Lindegren, M.A.C. Perryman

Using Hipparcos Transit Data for Aperture Synthesis Imaging 257

C. F. Quist, L. Lindegren, S. Soderhjelm

A Statistical Study of the Visual Double Stars in the Tycho Catalogue 263

J.-L. Halbwachs, S. Piquard, P. Virelizier, J. Cuypers, P. Lampens, E. Oblak

Classification of Red Variables 269

J.A. Mattei, G. Foster, L.A. Hurwitz, K.H. Malatesta, L.A. Willson, M.O. Mennessier

New Aspect of Long-Period Variable Stars from Hipparcos: First Results 275

M.O. Mennessier, J.A. Mattei, X. Luri

POSTERS

The Properties of Main-Sequence Stars from Hipparcos Data 279

N. Houk, CM. Swift, C.A. Murray, M.J. Penston, J.J. Binney

Systematic Effects on Photometric Parallaxes for FGK Dwarfs and Subdwarfs 283

C. Jordi, E. Masana, X. Luri, J. Torra, F. Figueras

Unbiased Luminosity Calibrations for Hipparcos Data 287

F. Arenou, A. E. Gdmez

The Hipparcos Calibration of Absolute Magnitudes in the Vilnius Photometric System . . 291

V. Malyuto, V. Straizys, A. Kazlauskas

Definition of the Pleiades Main Sequence in the Hertzsprung-Russell Diagram 295

C.S. Hansen-Ruiz, F. van Leeuwen

VI Contents

Kinematic Analysis of Cepheus 0B3 299

E. Trullols, C. Jordi, D. Galadi-Enriquez

Luminosities and Velocities of OBN Stars from Hipparcos 303

M. Mammano, R. Margoni, G. Oliva, M. Cecconi, P.L. Bernacea

Calibration of Luminosity of Hot Stars (Preliminary Results) 307

B. Nicolet

Absolute Magnitude Calibration of Geneva Photometry: B-type Stars 311

N. Cramer

Photometric Variability of B and Be Stars 315

A.M. Hubert, M. Floquet, A.E. Gomez, V. Aletti

Absolute Magnitudes of Be Stars 319

D. Briot, N. Robichon, A.M. Hubert

Some Hipparcos Results for Late-Type Stars 323

M.A.T. Groenewegen, H. Schrijver, T. de Jong, S. Slijkhuis

The Hipparcos HR Diagram of S Stars: Probing Nucleosynthesis and Dredge-Up 327

S. Van Eck, A. Jorissen, S. Udry, M. Mayor, B. Pernier

Calculating the Mass of Horizontal-Branch Stars with Hipparcos 331

K.S. de Boer, M. Geffert, H.-J. Tucholke, J.H.K. Schmidt

The HR Diagram of G5-M3 Stars near the Giant Branch 335

D. Egret, A. Heck, J.-L. Vergely, P.C. Keenan

Metal Abundances of One Hundred Hipparcos Dwarfs 339

R.G. Gratton, E. Carretta, G. Clementini, C. Sneden

The HR Diagram of Metal-Deficient Stars 343

A. Bartkevicius, S. Bartasiute, R. Lazauskaite

The Evolutionary Status of High-Lithium, High-Activity Cool Dwarfs 347

F. Favata, G. Micela, S. Sciortino, F. D'Antona

A First Hipparcos Contribution to the Lithium Problem 351

F. Crifo, F. Spite, M. Spite

Barium Stars: Luminosity and Kinematics from Hipparcos Data 355

X. Luri, A. Gomez, M.O. Mennessier, F. Figueras, J. Torra, S. Grenier

Hipparcos Observations of Pre-Main-Sequence Stars 359

R. Wichmann, U. Bastian, J. Krautter, I. Jankovics, S.M. Rucinski

The Lower Part of the Instability Strip: Evolutionary Status of Delta Scuti Stars 363

Y.Y. Liu, A. Baglin, M. Auvergne, M.J. Goupil, E. Michel

Delta Scuti Stars in the HR Diagram 367

P. North, C. Jaschek, D. Egret

White Dwarfs Observed by Hipparcos 371

G. Vauclair, H. Schmidt, D. Koester, N. Allard

Testing the White Dwarf Mass-Radius Relation with Hipparcos 375

J.L. Provencal, H.L. Shipman, E. H0g, P. Thejll

The HR Diagram for Late-Type Nearby Stars as a Function of Helium and Metallicity . .379

Y. Lebreton, M.-N. Perrin, J. Fernandes, et al.

Oxygen-Rich Mira Variables: Near Infra-Red Luminosity Calibrations 383

R. Alvarez, M.-O. Mennessier, D. Barthes, X. Luri, J.A. Mattel

Contents vii

Detection of Rapid Photometric Variations in Mira-type Variables 387

P. de Laverny, M.O. Mennessier, F. Mignard, J.A. Mattei

Hipparcos Distances of X-ray Selected Stars: Implications on their Nature 391G. Micela, F. Favata, S. Sciortino

The Luminosity and Kinematics of a Sample of Hot Subdwarfs 395

R. Viotti, D. Cardini, A. Emanuele, M. Badiali

Beta Hydri (G2 IV): A Revised Age for the Closest Subgiant 397D. Dravins, L. Lindegren, D.A. VandenBerg

Hipparcos, VLA and CCD Observations of Cyg OB2 No. 5 401

M.E. Contreras, L.F. Rodriguez, M. Tapia, et al.

Hipparcos Astrometry and Radio Mapping of Peculiar Binary Systems 405

R. Viotti, M. Badiali, D. Cardini, A. Emanuele, T. IijimaEffective Temperature Determination of Eclipsing Binaries 409

C. Jordi, I. Ribas, A. Gimenez, J. Torra, E. Oblak

Hipparcos Observations of Symbiotic Stars 413

U. Munari, A. Renzini, P.L. Bernacca

Masses of Astrometric Binaries 417

C. Martin, F. MignardOn the Mass-Luminosity Relation 421

P. Lampens, J. Kovalevsky, M. FroeschU, G. Ruymaekers

Triple Star Parameters and Masses 425

S. Soderhjelm, L. Lindegren

Absolute Magnitudes of Several Peculiar Star Groups 429

C. Jaschek, D. Egret, J.-L. Vergely

The Bolometric Correction mboi- Hp 433

R. Cayrel, F. Castelli, D. Katz, C. Van't Veer, A. Gomez, M.-N. Perrin

Beta Pictoris: Back to the ZAMS 437

F. Crifo, A. Vidal-Madjar, R. Lallement, R. Ferlet, M. Gerbaldi

Search for Variables in the Tycho Epoch Photometry Annex B 441

S. Friedrich, M. Konig, A. Wicenec

Accurate Two-Colour Photometry and Astrometry for Hipparcos Double Stars 445

E. Oblak, J. Cuypers, P. Lampens, W. Seggewiss, M. Chareton, D. Duval

Utilisation of Hipparcos Data for Distance Determinations: Error, Bias and Estimation . . 449

X. Luri, F. Arenou

Low-Resolution Spectroscopy of RR Lyrae Stars in the Hipparcos Input Catalogue ....453

D. Martinez-Delgado, E.J. Alfaro

Absolute Magnitude Calibration for the W UMa-type Contact Binary Stars 457

S.M. Rucinski, H.W. Duerbeck

Masses and Gravities of Blue Horizontal Branch (BHB) Stars Revisited 461

U. Heber, S. Moehler, l.N. Reid

The Classification of Binary Stars with Composite Spectra 465

J.M. Carquillat, N. Ginestet, C. Jaschek

viii Contents

Sessions 5-6: Galactic Physics

(Chairs: U. Bastian & C. Chiosi)

Photometric Variability in the HR Diagram 467

L. Eyer, M. Grenon

The Kinematics of Main Sequence Stars from Hipparcos Data 473

J.J. Binney, W. Dehnen, N. Houk, C.A. Murray, M.J. Penston

Kinematic Evidence for Propagating Star Formation Induced by OB Associations....

479

F. Comeron, J. Torra, A.E. Gomez, C. Jordi

The Luminosity Function of Main Sequence Stars within 80 Parsecs 485

C.A. Murray, M.J. Penston, J.J. Binney, N. Houk

The Metallicity Distribution of Late-Type Dwarfs and the Hipparcos HR Diagram ....489

M. Haywood, J. Palasi, A.E. Gomez, L. Meillon

Structure and Evolution of Nearby OB Associations 495

P.T. de Zeeuw, A.G.A. Brown, J.H.J, de Bruijne, et al.

Synthetic Diagrams for the Interpretation of SFR and IMF 501

G. Bertelli, E. Nasi, A. Bressan, C. Chiosi

The Kinematics and Nature of Gould's Belt - a 30 Myr Old Star Forming Region ....

507

P.O. Lindblad, J. Palous, K. Loden, L. Lindegren

Young Stars: Irregularities of the Velocity Field 513

J. Torra, A.E. Gomez, F. Figueras, et al,

Identification of Moving Groups in a Sample of Early-Type Main-Sequence Stars 519

F. Figueras, A.E. Gomez, R. Asiain, et al.

Eggen's Moving Groups: Fact or Fiction? 525

J. Skuljan, P.L. Cottrell, J.B. Hearnshaw

Space Motions and Orbits of Globular Clusters 531

P. Brosche, M. Odenkirchen, M. Geffert, H.-J. Tucholke

Where does the Dark Halo of the Galaxy End? 537

M. Miyamoto, T. Tsujimoto

Candidates to the Catalogue of Nearby Stars from Tycho Astrometry and Photometry . ,541

V.V. Makarov

POSTERS

The Distribution of Nearby Stars in Phase Space Mapped by Hipparcos 545

E. Chereul, M. Creze, 0. Bienayme

Distributions and Motions of Nearby Stars defined by Objective Prism Surveys and Hipparcos 549

P.D. Hemenway, J.T. Lee, A.R. Upgren

Determination of the Luminosity Function up to Mv =9 551

J. Palasi

Stellar Distribution Functions in the Solar Neighbourhood 555

K. Van Caelenberg, H. Dejonghe

Contents be

Estimation of the Local Mass Density from an F-Star Sample Observed by Hipparcos ...559

H-A. Pham

Determination of the IMF in the Solar Neighborhood between 1.2 and 4 M© 563

V. Sabas

Analysis of Seven Nearby Open Clusters using Hipparcos Data 567

N. Robichon, F. Arenou, C. Turon, J.-C. Mermilliod, Y. Lebreton

New Results for Three Nearby OB Associations 571

R. Hoogerwerf, J.H.J, de Bruijne, A.G.A. Brown, J. Lub, A. Blaauw, P.T. de Zeeuw

Improved Methods for Identifying Moving Groups 575

J.H.J, de Bruijne, R. Hoogerwerf, A.G.A. Brown, L.A. Aguilar, P.T. de Zeeuw

Absolute Proper and Space Motions of Globular Clusters 579

M. Geffert, M. Hiesgen, J. Colin, B. Dauphole, C. Ducourant

Kinematics and Mv Calibration of K and M Dwarf Stars 583

A.R. Upgren, K.U. Ratnatunga, S. Casertano, E. Weis

Kinematics of Subdwarfs based on Hipparcos Parallaxes and Proper Motions 587

H. Jahreifi, B. Fuchs, R. Wielen

First Steps Toward the Determination of the Escape Velocity in the Solar Neighbourhood .591

L. Meillon, F. Crifo, A.E. Gomez, S. Udry, M. Mayor

Populations among High-Velocity Early-Type Stars 595

F. Royer

Kinematics of RR Lyrae Stars based on Hipparcos Proper Motions 599

R. Wielen, B. Fuchs, C. Dettbarn, H. Jahreifi, J. Rockmann

The Extinction in the Solar Neighbourhood from the Hipparcos Data 603

J.-L. Vergely, D. Egret, R. Freire Ferrero, B. Valette, J. Koppen

A New Tool for Studying Galactic Structure 607

R. Drimmel, R. Smart, M.G. Lattanzi

Computing the Tilt of the Velocity Ellipsoid for a Galaxy Mass Model 611

F. Bancken

The Motion of the Magellanic Clouds 615

P. Kroupa, U. Bastian

A Search for Stars Passing Close to the Sun 617

J. Garcia-Sdnchez, R.A. Preston, D.L. Jones, et al.

Kinematics of Disk Stars in the Solar Neighbourhood 621

A.E. Gomez, S. Grenier, S. Udry, et al.

X Contents

Session 7: Cosmic Distance and Age Scale

(Chair: C. Turon)

Hipparcos Parallaxes and Proper Motions of Cepheids and their Implications 625

M.W. Feast, P.A. Whitelock

Distances for 17 Nearby Galaxies based on the Hipparcos Calibration of the P-L Relation.629

G. Paturel, P. Lanoix, R. Gamier, et al.

The Absolute Magnitudes of RR Lyrae Stars 635

/. Fernley, T.G. Barnes, I. Skillen, et al.

The Absolute Magnitude of RR Lyrae Stars 639

T. Tsujimoto, M. Miyamoto, Y. Yoshii

The Distance of the Pleiades and Nearby Clusters 643

J.-C. Mermilliod, C. Turon, N. Robichon, F. Arenou, Y. Lebreton

Distances and Absolute Ages of Galactic Globular Clusters from Subdwarf Parallaxes. . .

651

R.G. Gratton, F. Fusi Pecci, E. Carretta, G. Clementini, C.E. Corsi, M.G. Lattanzi

POSTERS

Hipparcos Parallaxes of the Nearest Cepheids - Implicative of Binarity 657

L. Szabados

Age and Morphology of the Main Sequence from Hipparcos HR Diagram Data 661

M. Badiali, D. Cardini, A. Emanuele, V. Caloi, F. D'Antona, I. Mazzitelli

Contents XI

Sessions 8-10: Selected Highlights

(Chairs: E. H0g & J. Kovalevsky)

Runaway Stars and the Force Perpendicular to the Galactic Plane 665

P.O. Lmdblad, K. Loden, J. Palous, L. Lindegren

Distribution of Nearby Stars in Phase Space Mapped by Hipparcos 669

M. Crete, E. Chereul, 0. Bienayme, C. Pichon

The Impact of Hipparcos on the Catalogue of Nearby Stars 675

H. Jahreifi, R. Wielen

The Hyades: Distance, Structure and Dynamics 681

A.G.A. Brown, M.A.C. Perryman, J. Kovalevsky, et al.

The Impact of Hipparcos on the Old Problem of the Helium Content of the Hyades . . . ,687

G. Cayrel de Strobel, F. Crifo, Y. Lebreton

The Parallax of the Pleiades Cluster 689

F. van Leeuwen, C.S. Hansen Ruiz

Coravel Radial Velocity Surveys of Late-Type Stars of the Hipparcos Mission 693

S. Udry, M. Mayor, J. Andersen, et al.

Hipparcos Subdwarfs and Globular Clusters: Towards Reliable Absolute Ages 699

F. Pont, C. Charbonnel, Y. Lebreton, M. Mayor, C. Turon, D.A. VandenBerg

Astrometric Indications of Brown Dwarfs based on Hipparcos Data 705

H.-H. Bernstein

The Importance of Positioning Isolated Neutron Stars: the Case of Geminga 709

P.A. Caraveo, M.G. Lattanzi, G. Massone, et al.

The Galactic Warp in Hipparcos 715

R.L. Smart, R. Drimmel, M.G. Lattanzi

Towards an Improved Model of the Galaxy 721

J. Holmberg, C. Flynn, L. Lindegren

Statistical Astrometry based on a Comparison between FK5 and Hipparcos 727

R. Wielen, H. Schwan, C. Dettbarn, H. Jahreifi, H. Lenhardt

Astrometric Radial Velocities from Hipparcos 733

D. Dravms, L. Lindegren, S. Madsen, J. Holmberg

The Educational Potential of the Hipparcos Database 739

J.R. Percy

Xll Contents

Session 11: Prospects of Microarcsec Astrometry: the Science

(Chair: F. van Leeuwen)

The Scientific Goals of the GAIA Mission 743

M.A.C. Perryman, L. Lindegren, C. Turon

The Scientific Basis for the Space Interferometry Mission 749

D. Peterson, M. Shao

GAIA and the Hunt for Extra-Solar Planets 755

M.G. Lattanzi, A. Spagna, A Sozzetti, S. Casertano

The Stromvil Seven-Colour Photometric System for GAIA 761

V. Straizys, E. H0g, A.G. Davis Philip

A Relativistic Model for the GAIA Observations 767

F. De Felice, M.G. Lattanzi, A. Vecchiato, P.L. Bernacca

Parallel Acquisition of Radial Velocities and Metallicities for the GAIA Mission 771

F. Favata, M.A.C. Perryman

Contents xiii

Session 12: Prospects of Microarcsec Astrometry: the Projects

(Chair: F. Mignard)

DIVA - Towards Microarcsecond Global Astrometry 777

S. Roser, U. Bastian, K.S. de Boer, et al.

Optical Design for GAIA 783

E. H0g, U. Bastian, W. Seifert

Global Astrometry with the Space Interferometry Mission 789

A. Boden, S. Unwin, M. Shao

An Optical/Infrared Astrometric Satellite Project LIGHT 795

M. Yoshizawa, K. Sato, J. Nishikawa, T. Fukushima, M. MiyamotoGAIA: Global Astrometric Interferometer for Astrophysics 799

L. Lindegren, M.A.C. Perryman

POSTERS

A New Optical Configuration Proposed for GAIA 803

M. Cecconi, M. Gai, M.G. Lattanzi

Lagrangian L2 or Geostationary Orbit: A System Level Trade-Off for the GAIA Mission.807

0. Pace

Opto/Mechanical Analysis for the Space Interferometry Project GAIA 811

M. Cecconi, G. Rigoni, P.L. Bernacca

Simulated Dispersed Fringes of an Astrometric Space Interferometry Mission 815

R.-D. Scholz, U. Bastian

Use of Conjugate Gradient Methods for the Great-Circle Reduction 819

A. Ilin

Large-Scale Distortions of Hipparcos-like Coordinate Systems 823

V. V. Makarov

Astrometric and Photometric Performance of the Astrometric Interferometer Satellite DIVA 827

U. Bastian, R.-D. Scholz

Project STRUVE 831

A.E. Ilin, A.G. Butkevich, M.S. Chubey, et al.

GAIA Feasibility: Current Research on Critical Aspects 835

M. Gai, F. Bertinetto, M. Bisi, et al.

Closing Address 839

Papers Indexed by First Author 841

Symposium Participants 845

Subject Index 853