Multiple Stars across the H-R Diagram: Proceedings of the ESO Workshop held in Garching, Germany, 12-15 July 2005 (ESO Astrophysics Symposia)

Stars show a marked tendency to be in systems of different multiplicity, ranging from simple binaries and triples to globular clusters with several 10,000's of stars. The formation and evolution of multiple systems remains a challenging part of astrophysics, and the contributions in this book report on the significant progress that had been made in this research field in the last years. The reader will find a variety of research topics addressed, such as the dynamical evolution in multiple stars, the effects of the environment on multiple system parameters, stellar evolution within multiple stars, multiplicity of massive stars, pre-main sequence and intermediate mass stars, multiplicity of low-mass stars from embedded protostars to open clusters, and brown dwarfs and extrasolar planets in multiples. This book presents the proceedings of the ESO Workshop on Multiple Stars across the H-R Diagram held in the summer of 2005. Front Matter....Pages I-XIII Evolutionary Processes in Multiple Systems....Pages 1-10 Dynamics and Stability of Triple Stars....Pages 11-20 Multiple Stars: Physics vs. Dynamics....Pages 21-30 Gliese 225.2: An Old (Stable?) Quadruplet....Pages 31-35 Multiple Stars: Designation, Catalogues, Statistics....Pages 38-42 Radial-velocity Studies of Certain Multiple Systems....Pages 43-45 Spectral Disentangling Applied to Triple Systems: RV Crt....Pages 47-52 Evidence for Rapid Variability in the Multiple System 68 u Her....Pages 53-58 DG Leo: A Triple System with a Surprising Variety of Physical Phenomena....Pages 59-65 A Spectroscopic Study of HD 208905....Pages 67-70 The Suspected Binarity of the Nearby Flare Star Gl 424....Pages 71-74 The Ecology of Dense Star Clusters with Binaries....Pages 75-86 The Formation of Multiple Stars....Pages 87-99 Population of Dynamically Formed Triples in Dense Stellar Systems....Pages 101-106 Interferometric Studies of Multiple Stars....Pages 107-112 Interferometric Orbits of New Hipparcos Binaries....Pages 114-118 New Facts about δ Velorum: Fewer but Larger Components....Pages 119-123 Speckle Interferometry of Two Low-mass Triple Systems in the Solar Neighbourhood....Pages 125-128 Tertiary Companions to Close Spectroscopic Binaries....Pages 129-135 Spectroscopic Subcomponents in Visual Double Stars: The Most Probable Values of their Physical and Orbital Parameters.Application to the System WDS 14404+2159....Pages 137-140 Multiple Stars in the Field....Pages 141-153 Multiplicity of Chemically Peculiar Stars....Pages 155-161 Multiplicity of Contact Binary Stars....Pages 163-168 Extrasolar Planets in Double and Multiple Stellar Systems....Pages 169-182 Homogeneous Comparison of Directly Detected Planet Candidates: GQ Lup, 2M1207, AB Pic....Pages 183-191 Searching for Planets Around Stars in Wide Binaries....Pages 193-198 Multiplicity at the Very Low Mass End of the H-R Diagram....Pages 199-209 Spectroscopic Companions of Very Young Brown Dwarfs....Pages 211-217 The Observed Multiplicity of Low-mass Stars: From Embedded Protostars to Open Clusters....Pages 219-232 High-order Multiplicity of PMS Stars: Results from a VLT/NACO Survey....Pages 232-238 Accretion onto Binary YSOs Through Gap from Their Circum-binary Disk....Pages 239-244 The Nearest Pre-Main Sequence Multiple Stars....Pages 245-257 A Study of the Young Quadruple System AO Vel with a ZAMS Eclipsing BpSi Primary and PMS Companions....Pages 259-263 Multiplicity of Massive Stars....Pages 265-280 The Triple System θ 1 Orionis A in the Heart of the Orion Trapezium Cluster....Pages 281-288 The Primordial Binary Population in OB Associations....Pages 289-294 Multiplicity of Early-type Stars in the Field: Progress Report....Pages 295-298 Search for Low-mass Companions to X-ray Emitting A-type Stars....Pages 299-303 The ESO workshop “Multiple Stars across the H-R Diagram” was held in Garching on 12–15, July 2005. The topics included observations of multiple stars from ground and space, dynamical and stellar evolution in multiple systems, e?ects of the environment on multiplicity, formation and early e- lution of multiple stars, and special components of multiple stars (chemically peculiar stars, blue stragglers, brown dwarfs, etc.). Stars show a marked tendency to be in systems of di?erent multiplicity, 7 ranging from simple binaries and triples to globular clusters with N?10 . Modern observations give a frequency of binary and multiple stars in the Galactic ?eld of up to 70%, and between 5% and 20% of these systems are at least triple. There is evidence that the degree of multiplicity increases with primary mass. Many known multiple systems are too wide to have s- ni?cant physical interaction between their components. However, tidal and N-body dynamical interactions are important even in relatively wide s- tems and probably lead to the shrinkage of inner orbits. This sets the stage for spectacular evolutionary processes such as Roche-lobe over?ow, me- ers, supernovae, formation of special components, etc. Only recently did we realize that some of these processes require at least three stars. Theformationofmultiplesystemsremainsadi?cultandchallengingpart of astrophysics, although it has been addressed at the Workshop only brie?y. The ESO workshop "Multiple Stars across the H-R Diagram" was held in Garching on July 12-15, 2005. The topics included observations of multiple stars from ground and space, dynamical and stellar evolution in multiple systems, effects of the environment on multiplicity, formation and early evolution of multiple stars, and special components of multiple stars. Research on multiple stars has seen major developments during recent years due to the availability of large-aperture telescopes equipped with highly sophisticated instruments for multi-wavelength observations, of modern interfero S.hubrig, M. Petr-gotzens, A. Tokovinin (eds.). Includes Bibliographical References.