Active Close Binaries

Since the 1970s symposia or colloquia devoted to recent research on close binaries have been held around the world almost annually. At meetings of the General Assembly of the International Astronomical Union this topic has also been discussed in detail at presentations in various commission meetings and also as invited talks by leading astronomers in the field. In recent years, fundamental changes have taken place in the study of close binaries due to the improvements in observational techniques, extension of observations from X-ray to radio regions of the electromagnetic spectrum, and advances in theoretical studies. For more than a decade, a group of astronomers at Ege University Observatory has been concentrating on active close binaries with particular emphasis on the behaviour of the light curves of chromospherically active systems. Thus, we decided to organize an international meeting in Western Anatolia, where this part of Turkey had been the cradle for great developments in science during antiquity. KUljadasi, located only minutes away from Ephesus, one of the seven wonders of the world, was selected to be the meeting site. Close binary systems constitute a very rich source of information about the physical properties of the component stars. Some systems are eclipsing variables, where periodic recurrences of eclipses are observed as comparatively brief decreases in the total brightness of the binary system. Precise methods of photometric observations make it possible to obtain the light variations of these systems because of eclipses and other phenomena.

Proceedings of the NATO Advanced Study Institute, Kusadasi, Turkey, September 11-22, 1989

Zusammenfassung
Proceedings of the NATO Advanced Study Institute, Kusadasi, Turkey, September 11-22, 1989

Inhalt
Opening Remarks: Physical Causes of the Light Variations of Active Binary Systems and their Interpretation.- Opening Remarks: Physical Causes of the Light Variations of Active Binary Systems and their Interpretation.- 1. Interaction in Binaries and Algols.- Eclipsing Binaries as Astrophysical Laboratories and the Strange Case of Epsilon Aurigae.- Accretion Disks in Non-Degenerate Binaries.- Resolving the Puzzle of the W Serpentis Stars.- Extragalactic Interacting Binaries.- Effective Gravity-Darkening of Close Binary Systems.- Binary Activity at the Top of the Main Sequence: Y Cyg and U Oph.- Period Changes and Magnetic Cycles.- Absolute Dimensions of Classical Algol-Type Binaries.- Recent Results of Apsidal Motion Studies in Eclipsing Binaries.- On the Orbital Circularization of Close Binaries.- Stellar Structure and Evolution with respect to Binarity.- An Optimization Method for Solutions of Close Eclipsing Binaries.- Spectrophotometry of Algol-Type Binaries.- Complications in the Balmer-Line Spectrum of TT Hydrae.- An Optimization Technique for the Fourier Analysis of the Light Curves of Totally Eclipsing Systems of Algol Type.- The Algol-Type Binary U Coronae Borealis: a Triple?.- Interacting Binary CX Draconis.- Disk-Driven Precession in Active Close Binaries and in Active Galactic Nuclei.- Near-Contact Binary Stars.- Observations and Light Curve Analysis of Eclipsing Binaries of W UMa Type.- A Radial Velocity Search for Brown Dwarfs and the Low-Mass Companion.- Photometry of Some Close Binaries at the Ankara University Observatory.- Circularization, Synchronization, and Differential Rotation in Chromospherically Active Binaries.- 2. Binary Evolution and the Contact Question.- Do Thermally Decoupled Late-Type Contact Binaries Really Exist?.- The Evolution of the Period and Synchronization for Close G-type MS Binaries.- The A-Type W UMa System AW UMa.- Rotation and Activity.- Solar-Like Magnetic Structures in Active Close Binaries.- Starspot Lifetimes.- Tidal Torques and Magnetic Stellar Winds in RS CVn Binaries.- Flares on RS CVn and Related Binaries.- Activity and Evolution in RS CVn Systems.- Deciphering Long-Term Photospheric and Chromospheric Activity on the Contact Binary Binary VW Cephei.- Synoptic Doppler Imaging and Photometry of Spotted Chromospherically Active Stars.- Infrared Studies on Active Binaries and Circumstellar Matter.- Infrared Photometry of RS CVn Short-Period Systems.- On Chromospheric Emission and Photometric Variability of Active Late-Type Stars.- 3. High Energy Binaries and Exotic Objects.- Long-Term Observations of Active Binaries.- Similarities and Differences between the Light Variability of the K Giant and Dwarf Active Binaries HK Lac and BY Dra.- Recent Measures of Call H and K Chromospheric Fluxes in a Sample of RS CVn Systems.- Photometric Variability of II Peg.- Activity Cycle in the RS CVn System II Peg.- Low Flux Line Profiles on the IUE Spectra of II Peg.- A Photometric Study of UV Psc.- Novae and their Non-Spherically-Symmetric Explosions.- Optical Properties of Cataclysmic Variable Stars.- IUE Spectra of Cataclysmic Variables: Observational Results and Theoretical Implications.- Binaries and Pulsars as Gravitational Wave Sources: Possibility of Direct Detection by Ground Based Experiments.- Neutron Star Masses.- High Angular Resolution Studies of Binaries at Georgia State University.- Extreme Ultraviolet Spectroscopy as a Probe of Active Close Binaries.- 4. Cool Close Binaries and RS CVn Stars.- Modelling the Coronae and Chromospheres of RS CVn Systems by the Analysis of Ultraviolet, X-Ray and Radio Observations.- Magnetic Flares in Close Binaries.- The Evolution of Chromospheric Stucture on AR Lacertae.- Spatial Resolution of Stellar Atmospheres within Active Close Binaries.- Information Limit Optimization Techniques Applied to AB Dor.- The Complementarity of Doppler Imaging and Starspot Modelling.- Perspectives for Ground-Based and Space Research on Active Close Binaries.- Unified Treatment of Satellite Motion in Various Potential Fields.- Light Curve Variations of the RS CVn Type Eclipsing Binary ER Vulpeculae.- Synthesis Methods for Eclipsing Binary Light Curves.- Types of Contact Binary Systems and Ways to Find Them.- A Photometric Analysis of Eclipsing Systems in NGC188.