Pulsation, rotation, and mass loss in early-type stars : proceedings of the 162nd symposium of the International Astronomical Union held in Antibes, Juan-les-Pins, France, October 5-8, 1993

In This Symposium, Researchers Specializing In Pulsation, Rotation, Magnetic Fields And Stellar Winds Are Brought Together For The First Time In Order To Broaden Our Understanding Of O And B Stars. Thanks To Advances In Digital Spectroscopy, New Types Of Pulsating B Stars Have Been Discovered. The Pulsations Can Be Understood In Terms Of The Recent Revision Of Metal Opacities, But The Effects Of Rapid Rotation And Magnetic Fields Need Further Study. Observations In The Uv And X-ray Regions Demonstrate That Many B And Be Stars Show Other Activity, Besides Pulsation Which Is Not Yet Understood. The Reason For The Enhanced Mass Loss In Be Stars Is A Question Which Dominates The Symposium And Which Remains Unanswered, Although It Is Surely To Be Found In Activity At Or Near The Photosphere Coupled With Rotation. It Is Shown That The Geometry Of The Circumstellar Envelopes Around Be Stars Is Indeed A Flattened Disk As They Can Now Be Optically Resolved. The Variability Of Radiatively-driven Winds From O And B Stars Are Likely Related To The Rotation Of The Star. This Underlines The Central Theme Of The Book: That The Various Phenomena Seen In These Stars Cannot Be Studied In Isolation. 1. Pulsation And Rotation -- 2. Magnetic Fields -- 3. X-ray Observations -- 4. Polarization -- 5. Be Stars: Spectroscopy And Photometry -- 6. Be Star: Circumstellar Environment -- 7. Ob Stellar Wind. Edited By Luis A. Balona, Huib F. Henrichs, And Jean Michel Le Contel. Includes Bibliographical References And Indexes. Front Matter....Pages i-xxii Front Matter....Pages 1-1 Observations of Pulsating OB Stars....Pages 3-14 Nonadiabatic Observables in β Cephei Star Models....Pages 15-16 Multiwavelength Studies of β Cephei Stars....Pages 17-18 Nonlinear Pulsational Behaviour of BW Vulpeculae....Pages 19-20 Stability of the Pulsation of 12 (DD) Lacertae....Pages 21-22 Period Variations in the Beta Cep Star α Lup....Pages 23-24 Period Variations in the Beta Cep Star β Cru....Pages 25-26 High-Resolution Spectroscopy of Beta Cephei Stars....Pages 27-28 A Search for Beta Cephei Stars in LMC and SMC....Pages 29-30 Photometric Variability in Early B Stars I. 53 Arietis....Pages 31-32 Multiperiodicity in Light Variations of 53 Persei: Results from Optical Photometry in 1990 October –1991 January....Pages 33-36 NRP Mode Typing for 53 Persei: Results From Voyager Photometry....Pages 37-38 Photometric and Spectroscopic Observations of the 53 Per Star: ζ CAS....Pages 39-40 HD 37151: A New “Slowly Pulsating B Star”....Pages 41-42 The Peculiar Binary System HR 8891 (ET And)....Pages 43-46 Spectroscopical Analysis of δ Scuti Stars....Pages 47-48 STACC....Pages 49-50 Tams Companions of Classical Cepheids....Pages 51-52 Pulsation of Wolf—Rayet Stars: WR40....Pages 53-54 The New Opacites and B-Star Pulsations....Pages 55-66 Front Matter....Pages 1-1 Convective Zones in the Envelope of Massive Stars....Pages 67-68 g-Mode Instability in the Main Sequence B-Type Stars....Pages 69-69 OP Versus OPAL Opacities: Consequences for B Star Oscillations....Pages 70-72 The Stability of Massive Stars....Pages 73-74 Mode Identification in Pulsating Stars....Pages 75-86 Amplitude Variations in Rotationally Split Multiplets....Pages 87-88 Line Profile Variations in Be Stars....Pages 89-99 Pulsations of Be Stars: Time Series Analysis of He I λ4921....Pages 100-101 Activity of the Be Star 28 Cygni: 1985–1991....Pages 102-103 Seismology of Southern Be Stars....Pages 104-105 Rapid Spectroscopic and Photometric Variability in the Be Star Alpha Eridani....Pages 106-107 A Survey of Line Profile Variations in Non-Emission Line B0-B5 III-V Stars....Pages 108-109 MUSICOS 92 Observations of θ 2 Tauri....Pages 110-111 Time-Series Analysis of the O4 Supergiant ς Puppis....Pages 112-113 Photospheric and Circumstellar Variability of the Rapidly Rotating O Star HD 93521....Pages 114-115 Pulsation in Rapidly Rotating Stars....Pages 117-127 Overstability of Nonradial Pulsations in Rotating Early Type Stars....Pages 128-129 The Evolution of Rotating 15 M ⊙ Stars....Pages 131-144 Rotationally Induced Turbulent Diffusion in Early B-Type Stars: Theory and Observations....Pages 145-146 Effects of Rotation on the Main Sequence Evolution of a 5 M ⊙ Star....Pages 147-148 Front Matter....Pages 1-1 The Abundance Anomalies in a Rotationally Evolved 20 M ⊙ OBN Star Model....Pages 149-150 Main-Sequence Broadening, Be Stars, and Stellar Rotation in h and χ Persei....Pages 151-152 Front Matter....Pages 153-153 Observations of Magnetic Fields in B Stars....Pages 155-166 Mass Loss, Magnetic Field and Chemical Inhomogeneities in the He-Weak Star HD 21699....Pages 167-168 The He-Strong Star HD 96446: Oblique Rotator or Pulsating Magnetic Variable?....Pages 169-170 The Circumstellar Environment of σ Orionis E....Pages 171-172 The Magnetic Fields of the A and B Stars....Pages 173-183 Fossil Magnetic Fields and Rotation of Early-Type Stars....Pages 184-185 Front Matter....Pages 187-187 Rosat Observations of B and Be Stars....Pages 189-199 X-ray Properties of Early-Type Stars....Pages 200-201 Effects of X-rays on the Ionization State of Be Star Winds....Pages 202-203 Infrared Spectroscopy of Be/X-ray Binaries....Pages 204-205 Multiwavelength Observations of the Be-star / X-ray Binary EXO2030+375 During Outburst....Pages 206-207 Exosat Observations of the Be/X-ray Binaries 2S0114+65 and 4U2206+54....Pages 208-210 Photometric and H α Observations of LSI+61°303....Pages 211-212 Be Star Disk Structure as Implied by X-ray Observations....Pages 213-215 Front Matter....Pages 217-217 Recent Results from Ultraviolet and Optical Spectropolarimetry of Hot Stars....Pages 219-229 Spectropolarimetric determination of circumstellar disc inclinations....Pages 230-231 The Polarization of H ß in γ Cas....Pages 232-233 Long-Term Spectroscopic and Polarimetric Variations of the Be Star к Dra....Pages 234-235 Front Matter....Pages 217-217 Common Properties of Some Be Stars Optical Polarization Parameters....Pages 236-237 Front Matter....Pages 239-239 Photospheric Activity in Selected Be Stars: λ Eri and γ Cas....Pages 241-253 Rapid Variability of H α Emission Line in Be Stars....Pages 254-256 Emission-Like Feature Due to a Latitudinal Differential Rotation....Pages 257-258 Study of the Hei λ4471 Line-Profile of be Stars....Pages 259-260 The HeI λ4471 Line Behaviour of 31 PEG....Pages 261-262 The FeII λ5317 Line Profile of Nine Be Stars....Pages 263-264 Fe II Line Widths as Tracers for the Geometry of Be Star Envelopes....Pages 265-266 FeII, FeIII and MgII spectra of Be stars....Pages 267-268 Spectroscopy of Be Stars in NGC 330....Pages 269-270 Be Stars in Young LMC Clusters....Pages 271-272 Puzzling Problems of He I Line Formation in Early B Stars....Pages 273-274 Be Stars in the Ultraviolet Spectral Classification System....Pages 275-276 UV Spectral Classification and Stellar Winds in a Sample of Be and Standard Stars....Pages 277-279 Analysis of IUE Spectrograms for Be stars....Pages 280-281 First Results of an International Multisite Multitechnique Campaign on omicron and....Pages 282-283 Results from Six Multiwavelength Campaigns to Study Short-Term FUV Flux Variability and Phase-Dependent Mass Loss in Be Stars....Pages 284-286 Periodic Variations and Mass Loss in Be Stars....Pages 287-298 Photometric Studies of Be Star Variability....Pages 299-300 Photometric Characteristics of the Be Stars: Almost Twenty Years of UBV Monitoring at the Hvar Observatory....Pages 301-302 Front Matter....Pages 239-239 Photometry of Early Type Stars in Open Clusters (NGC 1444, NGC 1662, NGC 2129, NGC 2169 and NGC 7209)....Pages 303-304 Rapid Multicolour Variations of Selected Southern Be Stars....Pages 305-306 Simultaneous Photometry and Spectroscopy of the Rapid Variability of the Be Star η Cen....Pages 307-308 Simultaneous uvbyβ Photometry and H α Spectroscopy of Be Stars in Open Clusters....Pages 309-310 Periodic Variability of Be Stars: Nonradial Pulsation or Rotational Modulation?....Pages 311-324 Line-Profile Variable ε Per: Spectroscopic Binary and (?) Mild Be Star....Pages 325-326 An Improved Model of the B0.5e + Be Binary System φ Per....Pages 327-328 HdBe Stars: Hydrogen-Deficient Supergiants with Emission Lines....Pages 329-330 Spectroscopic Analyses of HdBe Stars....Pages 331-332 Detection of calcium abundance stratification in Ap Stars....Pages 333-334 Stark Widths of Astrophysically Important Four-and Five-Times Charged Ion Lines....Pages 335-336 Stark Broadening of Stellar Pt II Lines....Pages 337-338 Front Matter....Pages 339-339 Variability in the Circumstellar Envelope of Be Stars....Pages 341-350 Physics of the Phase Changes of Be Stars....Pages 351-353 Difference between Be Stars and Shell Stars from H α Emission....Pages 354-355 The Number of Be Stars Compared with the Number of B Stars, Taking into Account the Specific Physical Characteristics of Be Stars....Pages 356-357 Shell Profiles in Be Star Spectra....Pages 358-359 Phase Changes in Be Stars: The Be-shell and Be phases of Pleione....Pages 360-361 The Photosphere of Pleione....Pages 362-363 Short-Term Spectroscopic Variations of the Southern Be Star 48 Lib....Pages 364-365 Front Matter....Pages 339-339 Structure of the Envelope of 48 Lib....Pages 366-367 Growth of the Line-Profile Variation Region during Be Episodes....Pages 368-369 70 Years of Observations of 4 Her: Changes through Three Shell Episodes....Pages 370-371 Activity in the Circumstellar Envelope of the Be/Shell Star ζ Tau....Pages 372-373 Period Dependent Variations of the Shell Spectrum of V923 Aql....Pages 374-375 Long-Term Periodic Variability in UV Absorption Lines of the Be Star γ Cas: On the Relation with V/R Variations in the H β Line....Pages 376-377 On the Formation of Balmer Emission Lines in the Model Envelopes of Be Stars....Pages 378-379 Some Observational Appearances of m=1 Density Waves in Be Star Disks....Pages 380-381 Global Disk Oscillations: Theoretical Line Profiles....Pages 382-383 Global Oscillations in Be Star Envelopes: Observational Evidence....Pages 384-385 Rapid Line Profile Variability of Hα in Two A0e Herbig Stars of the P Cyg-Subgroup and a Model for Their Circumstellar Envelope....Pages 386-388 Profile Variability of Hα in the B3e Herbig Star HD 200775 as Indication of Matter Infall and Inhomogeneous Stellar Wind....Pages 389-391 Dust and Gas in Shells Around Herbig Ae/Be Stars....Pages 392-393 Circumstellar Environment of the B[e] Star MWC 349 (V 1478 Cyg)....Pages 394-395 MWC 314 — A New Galactic B[e] Supergiant....Pages 396-397 The Structure of the Circumstellar Material in Be Stars....Pages 399-411 Infrared Spectroscopy of Be Stars....Pages 412-413 Infrared Emission Lines of Mg II in B Stars....Pages 414-415 Identifying Near-IR Variable Be Stars....Pages 416-417 Structure of the Circumstellar Envelope of ψ Persei at Large Radii....Pages 418-419 Front Matter....Pages 339-339 A Hidden Class of Be Stars?....Pages 420-421 Energy Distribution of Be Stars....Pages 422-424 Continuous Spectra of Circumstellar Envelopes of Be Stars....Pages 425-426 High—Precision Continuum Rectification....Pages 427-428 IR-Radio Spectral Indices for Be Stars....Pages 429-430 Problems of Modelization of Circumstellar Matter Out of Equilibrium....Pages 431-433 Optical Resolution of Be Star Envelopes....Pages 435-447 Candidates of Be Stars for GI2T Interferometry....Pages 448-449 Seven Be Stars Resolved by Optical Long-Baseline Interferometry....Pages 450-451 Front Matter....Pages 453-453 The Wind-Compressed Disk Model....Pages 455-468 Two-Dimensional Hydrodynamical Simulations of Wind-Compressed Disks Around Rapidly Rotating B-Stars....Pages 469-469 Latitude Dependent Radiative Wind Model for Be Stars: Line Profiles and Intensity Maps....Pages 470-472 Continuum Flux and Polarization in B[e] Supergiants....Pages 473-474 The Basic Physics of Hot-Star Winds....Pages 475-486 Radiatively Driven Winds of OB Star....Pages 487-489 Radiation-Accellerated Ions in Hot Star Winds: Heating and “Turbulence” Effects....Pages 490-491 A simple model for a radiatively driven metallic wind in A0 stars....Pages 492-493 Smooth Winds and Clumped Winds for Early-Type Stars....Pages 494-495 Line Profiles in Expanding Atmospheres....Pages 496-497 Non-Thermal Velocities in the Stellar Wind of Early-Type Stars....Pages 498-499 Front Matter....Pages 453-453 Understanding the P Cygni Profile....Pages 500-501 Improved Modelling for Spatially Resolved Spectroscopy of A P Cyg Envelope....Pages 502-504 The Hard Life of Clumps in Atmospheres of Early-Type Stars....Pages 505-506 Time-Dependent Phenomena in OB Star Winds....Pages 507-516 Wind Variability in O-Type Stars....Pages 517-529 International Multiwavelength Campaigns on Short-Term Variability of OB Stars: Optical Polarimetry....Pages 530-531 High Resolution Spectroscopy at the ESO 50 cm Telescope: Spectroscopic Monitoring of Luminous Hot Stars....Pages 532-533 The Stellar Wind of X 2 Ori and Its Variability....Pages 534-535 Observed variety of timescales in variability of P Cygni....Pages 536-537 Stellar Winds in A-Type Supergiants....Pages 538-539 Back Matter....Pages 541-550 "In this Symposium, researchers specializing in pulsation, rotation, magnetic fields and stellar winds are brought together for the first time in order to broaden our understanding of O and B stars. Thanks to advances in digital spectroscopy, new types of pulsating B stars have been discovered. The pulsations can be understood in terms of the recent revision of metal opacities, but the effects of rapid rotation and magnetic fields need further study. Observations in the UV and X-ray regions demonstrate that many B and Be stars show other activity besides pulsation which is not yet understood. The reason for the enhanced mass loss in Be stars is a question which dominates the Symposium and which remains unanswered, though it is surely to be found in activity at or near the photosphere coupled with rotation. It is shown that the geometry of the circumstellar envelopes around Be stars is indeed a flattened disk as they can now be optically resolved. The variability of radiatively-driven winds from O and B stars are likely related to the rotation of the star. This underlines the central theme of the book: that the various phenomena seen in these stars cannot be studied in isolation."--BOOK JACKET