O. Yu. Malkov

Dynamical masses of a selected sample of orbital binaries

Orbital binary stars are essential objects for determining dynamical and physical properties of stars through a combined analysis of photometric and astrometric data. We compiled a set of orbital binaries with known trigonometric parallaxes and orbits of high quality, using data from current versions of the Catalogue of Orbits and Ephemerides of Visual Double Stars and the Sixth Catalog of Orbits of Visual Binary Stars as well as including updated information from WDS and SIMBAD. We constructed distributions of orbital binaries among dynamical mass, period, semi-major axis, and eccentricity of systems, which characterize the set. Some problems related to the parameterization of orbital binaries are also discussed in the paper.

A procedure for the classification of eclipsing binaries

A procedure for the automatic classification of eclipsing binaries is presented. The procedure is based on the data from 1029 classified systems and allows for the classification of a given system based on a set of observational parameters, even if the set is incomplete. The procedure is applied to six large surveys of eclipsing variables. About 5300 systems were classified for the first time and can be used for the determination of the astrophysical parameters of their components.

Accuracy of stellar parameters determined from multicolor photometry

The development and application of new methods for intelligent analysis and extraction of information from digital sky surveys carried out in various spectral domains have now become a popular field in astrophysical research and, in particular, in stellar studies. Modern large-scale photometric surveys provide data for 105–106 relatively faint objects, and the lack of spectroscopic data can be compensated by the cross identification of the objects followed by an analysis of all catalogued photometric data. In this paper we investigate the possibility of determining the effective temperature, surface gravity, total extinction, and the total-to-selective extinction ratio based on the photometry provided in the 2MASS, SDSS, and GALEX surveys, and estimate the accuracy of the inferred parameters. We use a library of theoretical spectra to compute the magnitudes of stars in the photometric bands of the above surveys for various sets of input parameters. We compare the differences between the computed magnitudes with the errors of the corresponding surveys. We find that stellar parameters can be computed over a sizable domain of the parameter space. We estimate the accuracy of the resulting parameters. We show that the presence of far-ultraviolet data in the available set of observed magnitudes increases the accuracy of the inferred parameters.

Cross-Identification of Large Surveys for Finding Interstellar Extinction

The publication of large photometric surveys and the tools for the cross-identification of their objects open up a possibility for obtaining multicolor photometry of hundreds of millions of objects. This, in turn, makes it possible not only to classify the objects and determine their parameters, but also to measure the interstellar extinction towards them and produce an extinction map for the Milky Way. The aim of this study is to develop a tool for the cross identification of objects in the most well-known surveys and test it in several sky areas. To this end, we implemented an algorithm of fast positional matching of large astronomical catalogs in small (up to one degree) sized areas with filtering of false identification. As a result, we drew in seven 0.1-degree radius areas samples of objects from the DENIS, 2MASS, SDSS, GALEX, and UKIDSS surveys, and performed the cross-identification of these surveys. We compiled the corresponding subcatalogs in the VO Table format. The tool developed as a result of this work can be used to cross-identify objects in arbitrary sky areas for the further classification and determination of stellar parameters, including the measurement of the amount of interstellar extinction.

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.

Web-Resources for Astronomical Data in the Ultraviolet

In this paper we describe databases of space projects that are operating or have operated in the ultraviolet spectral region. We give brief descriptions and links to major sources for UV data on the web: archives, space mission sites, databases, catalogues. We pay special attention to the World Space Observatory—Ultraviolet mission that will be launched in 2021.

On the Astron UV Space Mission Data

Abstract The Soviet UV space mission Astron, launched in 1983, had been operational for eight years as the largest ultraviolet space telescope during its lifetime. Astron provided a lot of observational material for various types of astrophysical objects, but unfortunately these data were not widely available and, as a result, unduly forgotten. Here we present some results of our comparison of the Astron data to the modern UV stellar data, such as the NGSL spectral library, discuss the precision and accuracy achieved with Astron, and make some conclusions on potential application areas of these data.

Observations of Two Unusual Eclipsing Binaries, FN Cam and AG Vir

Abstract Based on the results of classification of eclipsing binaries, we have compiled a list of stars that are promising objects for future study. We have started an observational campaign with telescopes of the Kourovka Observatory, Russia and present the first results of this work.

Catalogue of Bright IDS Stars with Extensive Cross-Identifications

Abstract A new catalogue of bright binary stars is presented. The catalogue1 includes bright IDS systems and bright spectroscopic binaries. Besides IDS data (coordinates, relative positions, magnitudes and spectral classification), the catalogue contains extensive cross-identification and comments for 27452 systems. The catalogue is complete to the 9th mag, but also contains stars down to about 16th mag.