Dana Kovaleva

Age and metallicity estimates for moderate-mass stars in eclipsing binaries

We estimate the ages and metallicities for the components of 43 binary systems using a compilation of accurate observational data on eclipsing binaries for which lines of both components are visible in their spectra, together with two independent modern sets of stellar evolution models computed for a wide range of masses and chemical abundances. The uncertainties of the resulting values are computed, and their stability is demonstrated. The ages and metallicity are compared with those derived in other studies using different methods, as well as with independent estimates from photometric observations and observations of clusters. These comparisons con firm the reliability of our age estimates. The resulting metallicities depend significantly on the choice of theoretical model. Comparison with independent estimates favors the estimates based on the evolutionary tracks of the Geneva group.

Conceptual approach to astronomical problems

New technical capabilities have brought about the sweeping growth of the amount of data acquired by the astronomers from observations with different instruments in various parts of the electromagnetic spectrum. We consider conceptual approach to be a promising tool to efficiently deal with these data. It uses problem domain knowledge to formulate the tasks and develop problem-solving algorithms and data analysis methods in terms of domain concepts without reference to particular data sources, and thereby allows solving certain problems in general form. We demonstrate the benefits of conceptual approach by using it to solve problems related to search for secondary photometric standard candidates, determination of galaxy redshifts, creation of a binary and multiple star repository based on inhomogeneous databases, and classification of eclipsing binaries.We formulate and solve these problems over specifications of astronomical knowledge units such as photometric systems, astronomical objects, multiple stars, etc., and define them in terms of the corresponding problem domains independently of the existing data resources.

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

Abstract 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 (http://www.inasan.ru), due to necessity of a unified and consistent system for designation of objects in the database, and the name of the designation scheme was derived from that of the database. The BSDB scheme covers all types of observational data. Three classes of objects introduced within the BSDB nomenclature provide correct links between objects and data, what is especially important for complex multiple stellar systems. The final stage of establishing the BSDB scheme is compilation of the Identification List of Binaries, ILB, where all known objects in binary and multiple stars are presented with their BSDB identifiers along with identifiers according to major catalogues and lists.

Matching and Verification of Multiple Stellar Systems in the Identification List of Binaries

Binary and multiple stellar systems have been observed using various methods and tools. Catalogs of binaries of different observational types are independent and use inherent star identification systems. Catalog rows describing components of stellar systems refer to identifiers of surveys and catalogs of single stars. The problem of cross-identification of stellar objects contained in sky surveys and catalogs of binaries of different observational types requires not only combining lists of existing identifiers of binary stars, but rather matching components and of multiple systems and pairs of components by their astrometric and astrophysical parameters. Existing identifiers are verified for belonging to matched components, pairs and systems. After that, they may be matched to one another. The framework of multiple system cross-matching presented in the paper uses domain knowledge of binaries of different observational types to form sets of matching criteria. The Identification List of Binaries (ILB) has been created after accurate matching of systems, their components and pairs of all observational types. This work continues research of binary and multiple system identification methods.

Identification List of Binaries

Abstract The Identification List of Binaries (ILB) is a star catalogue constructed to facilitate cross-referencing between different catalogues of binary stars. As of 2015, it comprises designations for approximately 120 000 double/multiple systems. ILB contains star coordinates and cross-references to the Bayer/Flemsteed, DM (BD/CD/CPD), HD, HIP, ADS, WDS, CCDM, TDSC, GCVS, SBC9, IGR (and some other X-ray catalogues), PSR designations, as well as identifications in the recently developed BSDB system. ILB eventually became a part of the BDB stellar database.

Binary Star Database (BDB): New Developments and Applications

Binary star DataBase (BDB) is the database of binary/multiple systems of various observational types. BDB contains data on physical and positional parameters of 260,000 components of 120,000 stellar systems of multiplicity 2 to more than 20, taken from a large variety of published catalogues and databases. We describe the new features in organization of the database, integration of new catalogues and implementation of new possibilities available to users. The development of the BDB index-catalogue, Identification List of Binaries (ILB), is discussed. This star catalogue provides cross-referencing between most popular catalogues of binary stars.

Hidden Population of Algols

Abstract We present the results of Monte Carlo simulation aiming to estimate the frequency of semi-detached Algol-type binaries among the stars observed as single. When an account is taken of various detection biases (mostly due to inclination of orbits), the fraction of Algols among the Galactic disk stars appears to be 0.1–0.2%. However, this number should be regarded as a lower limit only, since there are still unaccounted-for selection effects and other types of photometrically unresolved binaries. Hidden binarity appears to be an important phenomenon that should be taken into account when considering stellar statistics and constructing the fundamental relations between stellar parameters.

Visual Binary Stars: Data to Investigate Formation of Binaries

Abstract Statistics of orbital parameters of binary stars as well as statistics of their physical characteristics bear traces of star formation history. However, statistical investigations of binaries are complicated by incomplete or missing observational data and by a number of observational selection effects. Visual binaries are the most common type of observed binary stars, with the number of pairs exceeding 130 000. The most complete list of presently known visual binary stars was compiled by cross-matching objects and combining data of the three largest catalogues of visual binaries. This list was supplemented by the data on parallaxes, multicolor photometry, and spectral characteristics taken from other catalogues. This allowed us to compensate partly for the lack of observational data for these objects. The combined data allowed us to check the validity of observational values and to investigate statistics of the orbital and physical parameters of visual binaries. Corrections for incompleteness of observational data are discussed. The datasets obtained, together with modern distributions of binary parameters, will be used to reconstruct the initial distributions and parameters of the function of star formation for binary systems.

THE RUSSIAN VIRTUAL OBSERVATORY: INFORMATION HUB

The Russian Virtual Observatory (RVO) will be an integral component of the International Virtual Observatory, which will link the archives of all the worlds major observatories into one distributed database, with powerful tools to optimize the extraction of science from the data. As a result, data from all the worlds major observatories will be available to all professional astronomers, and to the public. The information hub of the RVO has the main goals of integrating resources of astronomical data accumulated in Russian observatories and institutions and providing transparent access for scientific and educational purposes to the distributed information and data services. One of the general-purpose data centres for astronomy is the Moscow Centre for Astronomical Data (CAD). CAD has been systematically collecting and distributing astronomical data for more than 20 years. The CAD staff will carry out the activities on construction of the information hub of the RVO.