Astronomical Data Resources for Binary and Multiple Stars

Binary stars form a significant part of stellar population. They are registered and observed by a number of methods. This is the reason for variety of present-day resources of astronomical data dealing with binaries and multiples. The review of observational types of binary stars and of basic data resources for them is presented. The properties of stars within these types and possible relationships between them are discussed. The Binary star DataBase, BDB (http://bdb.inasan.ru), is presented as the resource joining data for all observational types of binaries. The problem of correct cross-identification of objects within binary and multiple stars is being solved in the frame of the Identification List of Binaries (ILB).

DIVISION G COMMISSION 26: DOUBLE & MULTIPLE STARS

This report covers the workings of Commission 26 over the triennial period 2012-2015 and is the last report of the Commission. Included are reports from Working Groups and the Commission 26 Circular; all of which will be continuing in Commission G1 (Binary and Multiple Stars). Also included is a report of the Splinter Meeting of Commissions 26, 42 & G1, submitted observatory reports and a history of Commission 26.

BSDB: A New Consistent Designation Scheme for Identifying Objects in Binary and Multiple Stars

The new consistent scheme for designation of objects in binary and multiple systems, BSDB, is described. It was developed in the frame of the Binary star DataBase, BDB (

Roadmap on the theoretical work of BinaMIcS

We review the different theoretical challenges concerning magnetism in interacting binary or multiple stars that will be studied in the BinaMIcS (Binarity and Magnetic Interactions in various classes of Stars) project during the corresponding spectropolarimetric Large Programs at CFHT and TBL. We describe how completely new and innovative topics will be studied with BinaMIcS such as the complex interactions between tidal flows and stellar magnetic fields, the MHD star-star interactions, and the role of stellar magnetism in stellar formation and vice versa. This will strongly modify our vision of the evolution of interacting binary and multiple stars.

Quantitative Spectroscopy of Close Binary Stars

The method of spectral disentangling has now created the opportunity for studying the chemical composition in previously inaccessible components of binary and multiple stars. This in turn makes it possible to trace their chemical evolution, a vital aspect in understanding the evolution of stellar systems. We review different ways to reconstruct individual spectra from eclipsing and non-eclipsing systems, and then concentrate on some recent applications to detached binaries with high-mass and intermediate-mass stars, and Algol-type mass-transfer systems.

COMMISSION 42: CLOSE BINARY STARS

Two meetings of interest to close binaries took place during the reporting period: A full day session on short-period binary stars – mostly CV's – (Milone et al. 2008) during the 2006 AAS Spring meeting in Calgary and the very broadly designed IAU Symposium No. 240 on Binary Stars as Critical Tools and Tests in Contemporary Astrophysics in Prague, 2006, with many papers on close binaries [Hartkopf et al. 2007]. In addition, the book by Eggleton (2006), which is a comprehensive summary of evolutionary processes in binary and multiple stars, was published.

COMMISSION 26: BINARY AND MULTIPLE STARS

The Business Meeting of Commission 26 took place on 17 August 2006, during the IAU XXVI General Assembly in Prague. It was chaired by its outgoing president, William Hartkopf, and was attended by the following members and guests: H. Abt, C. Allen, W. van Altena, R. Argyle, G. van Belle, D. Bisikalo, A. Bradley, T. ten Brummelaar, D. Cline, T. Corbin, R. Costero, J. Davis, H. Dickel, J. Docobo, J. Echevarria, F. Fekel, E. Griffin, P. Harmanec, W. Hartkopf, P. Lampens, O. Malkov, B. Mason, H. McAlister, T. Oswalt, D. Pourbaix, A. Poveda, D. Raghavan, W. Sanders, C. Scarfe, W. Tango, A. Tokovinin, S. Urban, R. Wilson, and H. Zinnecker.