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.
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ISBN-13
978-3-540-74745-1 (9783540747451)
DOI
10.1007/978-3-540-74745-1
Schweitzer Klassifikation
Evolutionary Processes in Multiple Systems.- Dynamics and Stability of Triple Stars.- Multiple Stars: Physics vs. Dynamics.- Gliese 225.2: An Old (Stable?) Quadruplet.- Multiple Stars: Designation, Catalogues, Statistics.- Radial-velocity Studies of Certain Multiple Systems.- Spectral Disentangling Applied to Triple Systems: RV Crt.- Evidence for Rapid Variability in the Multiple System 68 u Her.- DG Leo: A Triple System with a Surprising Variety of Physical Phenomena.- A Spectroscopic Study of HD 208905.- The Suspected Binarity of the Nearby Flare Star Gl 424.- The Ecology of Dense Star Clusters with Binaries.- The Formation of Multiple Stars.- Population of Dynamically Formed Triples in Dense Stellar Systems.- Interferometric Studies of Multiple Stars.- Interferometric Orbits of New Hipparcos Binaries.- New Facts about ? Velorum: Fewer but Larger Components.- Speckle Interferometry of Two Low-mass Triple Systems in the Solar Neighbourhood.- Tertiary Companions to Close Spectroscopic Binaries.- Spectroscopic Subcomponents in Visual Double Stars: The Most Probable Values of their Physical and Orbital Parameters.Application to the System WDS 14404+2159.- Multiple Stars in the Field.- Multiplicity of Chemically Peculiar Stars.- Multiplicity of Contact Binary Stars.- Extrasolar Planets in Double and Multiple Stellar Systems.- Homogeneous Comparison of Directly Detected Planet Candidates: GQ Lup, 2M1207, AB Pic.- Searching for Planets Around Stars in Wide Binaries.- Multiplicity at the Very Low Mass End of the H-R Diagram.- Spectroscopic Companions of Very Young Brown Dwarfs.- The Observed Multiplicity of Low-mass Stars: From Embedded Protostars to Open Clusters.- High-order Multiplicity of PMS Stars: Results from a VLT/NACO Survey.- Accretion onto Binary YSOs Through Gapfrom Their Circum-binary Disk.- The Nearest Pre-Main Sequence Multiple Stars.- A Study of the Young Quadruple System AO Vel with a ZAMS Eclipsing BpSi Primary and PMS Companions.- Multiplicity of Massive Stars.- The Triple System ?1 Orionis A in the Heart of the Orion Trapezium Cluster.- The Primordial Binary Population in OB Associations.- Multiplicity of Early-type Stars in the Field: Progress Report.- Search for Low-mass Companions to X-ray Emitting A-type Stars.
