Absolute dimensions of 140 close binary systems

The absolute dimensions of 140 close binaries have been computed. These systems have been extracted from recent catalogues of photometric and spectroscopic elements.     

Prospects of high angular resolution measurements of binary stars properties with VLTI

We present a program for observations of spectroscopic binaries with VLTI. The aim of such observations is to obtain high accuracy measurements of stellar parameters, in particular masses, combining the visual orbit with spectroscopic orbital elements. We selected a sample of spectroscopic binaries, including pre-main sequence stars, using the estimated angular nodal separation as a criterion for feasibility. A cross-check with the 4th catalog of measurements of binary stars (Hartkopf, 2001) was carried out and we discuss the statistical properties of the sample. This revised version was published online in July 2006 with corrections to the Cover Date.     

Contribution to the study of F‐G‐K‐M binaries: XII. Orbital elements of seven new spectroscopic binaries

The orbital elements of seven single‐lined spectroscopic binaries, HD 31855, HD 59643, HD 60092, HD 133189, HD 162262, HD 203522, BD +43° 1331 are presented. They are obtained from observations made with two photoelectric spectrometers of CORAVEL type, the first located at the Observatoire de Haute‐Provence and the second at the Cambridge Observatories. From those orbital elements and other data available in the literature, we deduce some information about the unseen companions and their separations with respect to the primaries. We then discuss the rotation‐revolution synchronism and conclude that some of those stars have probably reached the state of (pseudo‐)synchronism. Finally we give a synopsis of the results obtained in this series of papers. Our radial velocity monitoring of more than three decades has allowed us to derive accurate orbital elements of 35 spectroscopic binaries, with a cool primary star of type F‐G‐K‐M. The corresponding range of periods varies from a few days to more than 10 years. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Der Einfluß des SCHWARZSCHILD-Effektes auf die Bahn-und Systemelemente lichtschwacher und kurzperiodischer spektroskopischer Doppelsternsysteme

The influence of the SCHWARZSCHILD effect on the orbital and system elements of weak and short-periodic spectroscopic binaries has been examined. It effects the observational times and phases by broadening the spectral lines. Analyzing two model system – a theoretical one and a real weak and short-periodic binary (BD + 57° 1942) – correction terms have been determined and their influence on the orbital and system elements by a method of WILSING and RUSSELL have been studied.     

Frequency of Be and Ae stars in spectroscopic binaries

The frequency of Be and Ae stars in spectroscopic binaries and Algol binaries is examined based on the available catalogue data, and compared with that of stars in theBright Star Catalogue. It is shown that in binary systems Be and Ae stars reveal different statistical behaviours. The frequency of Be stars in spectroscopic binaries shows a notable peak in its orbital-period distribution in the range of 100–300 days, suggesting a statistical group separated from Algol systems. In contrast, most of Ae stars in spectroscopic binaries belong to the Algol systems.     

Contribution to the study of composite spectra: XI. Orbital elements of some faint systems

We present the results of a radial‐velocity study of nine new faint SB1 spectroscopic binaries with composite spectra: HD 137975‐6, 177984, HDE 226489, 231613‐4, 255387‐8, 256138‐9, 264997‐8, 276787 and 293041‐2. The observations were made at Haute‐Provence and Cambridge observatories with CORAVEL instruments between 1982 and 2006. From the radial‐velocity measurements of the cool components, we derive the orbital elements of those spectroscopic binaries for the first time. Using all the available data, we propose a model for each system that describes the nature of the individual components, with an estimation of the angular separation and orbital inclination. Finally we discuss the rotation–revolution synchronism of the cool components. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Contribution to the search for binaries among Am stars – V. Orbital elements of eight short-period spectroscopic binaries

We present the results of a radial-velocity study of eight Am stars (HD 341, 55822, 61250, 67317, 93991, 162950, 224890 and 225137) observed at Observatoire de Haute-Provence with the CORAVEL instrument. We find that these systems are single-line spectroscopic binaries whose orbital elements are determined for the first time.     

Contribution to the study of composite spectra: XII. Spectroscopic orbits of eight southern stars

We present the results of a radial‐velocity study of eight southern SB1 spectroscopic binaries with composite spectra: HD 34318‐9, HD 47579‐80, HD 70442‐3, HD 74946‐7, HD 102171‐2, HD 120901‐2, HD 168701‐2, and HD 174191‐2. The observations were made at Haute‐Provence observatory with the CORAVEL instrument between 1982 and 2006. From the radial‐velocity measurements of the cool components, we derive the orbital elements of those spectroscopic binaries. Using all the available data, we obtain an estimation of the orbital inclination and the angular separation of the two components. Finally we discuss the rotation‐revolution synchronism of the cool components. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Binaries with Total Eclipses in the LMC: Potential Targets for Spectroscopy

35 Eclipsing binaries presenting unambiguous total eclipses were selected from a subsample of the list of Wyrzykowski et al. (2003). The photometric elements are given for the I curve in DiA photometry, as well as approximate teff and masses of the components. The interest of these systems is stressed in view of future spectroscopic observations.     

Radial Velocities of Six Early Type Evolved Stars

Many early-type main sequence stars are known spectroscopic binaries, while early type spectroscopic binaries with evolved components are rather rare and well-determined masses are available only in some cases. For this reason a program to study stars with suspected variable velocity among early-type evolved stars has been initiated some time ago. In the present paper 54 coudé spectra for a sub-group formed of six early-type stars, namely HD 7902, HD 28446, HD 42087, HD 187983, HD 195592 and HD 208501 have been measured and the results of these plates have been presented.     

The data mining II: An analysis of 33 eclipsing binary light-curves observed by the INTEGRAL/OMC

Thirty-three eclipsing binaries were selected for an analysis from a huge database of observations made by the INTEGRAL/OMC camera. The photometric data were processed and analyzed, resulting in a first light-curve study of these neglected eclipsing binaries. The system CY Lac was discovered to be an eccentric one. In several systems from this sample even their orbital periods have been confirmed or modified. Due to missing spectroscopic study of these stars, further detailed analyses are still needed.     

The spectroscopic study of astrometric binaries

The spectroscopic observations of several astrometric binaries, obtained by the author during the past 20 years, are described. Main emphasis is placed on the determination of orbital elements of visual binaries, and the detection of unseen companions.Communication presented at the International Conference on Astrometric Binaries, held on 13–15 June, 1984, at the Remeis-Sternwarte Bamberg, Germany, to commemorate the 200th anniversary of the birth of Friedrich Wilhelm Bessel (1784–1846).     

Low resolution spectroscopy of selected Algol systems

The analysis of spectroscopic data for 30 Algol-type binaries is presented. All these systems are short period Algols having primaries with spectral types B and A. Dominant spectral lines were identified for the spectra collected and their equivalent widths were calculated. All the spectra were examined to understand presence of mass transfer, a disk or circumstellar matter and chromospheric emission. We also present first spectroscopic and period study for few Algols and conclude that high resolution spectra within and outside the primary minimum are needed for better understanding of these Algol type close binaries.     

Contribution to the study of binaries with spectral types F,G, K,and M – XI. Orbital elements of three red‐giant spectroscopic binaries: HR 1304, HR 1908, and HD 126947

The orbital elements of three red‐giant single‐lined spectroscopic binaries, HR 1304, HR 1908 and HD 126947, are presented. They are obtained from observations made with two photoelectric spectrometers of CORAVEL type, the first located at the Observatoire de Haute‐Provence and the second at the Cambridge Observatories. HR 1304 and HR 1908 are known to be chromospherically active stars and to have high spatial velocities; HD 126947 is an intrinsic variable newly detected by Hipparcos. The three systems have long orbital periods: 1.9, 3.2 and 7.7 yr for HR 1304, HR 1908 and HD 126947, respectively. From the orbital elements that we determined and other data available in the literature, we deduce some information about the unseen companions and their separations with respect to the primaries. Finally we discuss the rotation–revolution synchronism and conclude that one star, HR 1908, may have reached the state of pseudo‐synchronism, despite of its long orbital period. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Origin of orbits of secondaries in the discovered trans-Neptunian binaries

The dependences of inclinations of orbits of secondaries in the discovered trans-Neptunian binaries on the distance between the primary and the secondary, on the eccentricity of orbits of the secondary around the primary, on the ratio of diameters of the secondary and the primary, and on the elements of heliocentric orbits of these binaries are studied. These dependences are interpreted using the model of formation of a satellite system in a collision of two rarefied condensations composed of dust and/or objects less than 1 m in diameter. It is assumed in this model that a satellite system forms in the process of compression of a condensation produced in such a collision. The model of formation of a satellite system in a collision of two condensations agrees with the results of observations: according to observational data, approximately 40% of trans-Neptunian binaries have a negative angular momentum relative to their centers of mass.     

A catalogue of close binaries located in the δ Scuti region of the Cepheid instability strip

A catalogue of close eclipsing binary systems (detached and semidetached) with at least one of the components located in the δ Scuti region of the Cepheid instability strip is presented. The positions of the stars in the instability strip are determined by their accurate temperatures and luminosities. Observationally detected binaries (20 semidetached, four detached and one unclassified) with oscillating components were included in the catalogue as a separate table. The primaries of the oscillating Algols tend to be located near the blue edge of the instability strip. Using reliable luminosities and temperatures determined by recent photometric and spectroscopic studies, we have found that at least one or two components of 71 detached and 90 semidetached systems are located in the δ Scuti region of the Cepheid instability strip. In addition, 36 detached or semidetached systems discovered by the Hipparcos satellite were also given as a separate list. One of their components is seen in the δ Scuti region, according to their spectral type or   B − V   colours. They are potential candidate binaries with the δ Scuti-type pulsating components which need further photometric and spectroscopic studies in better precision. This catalogue covers information and literature references for 25 known and 197 candidate binaries with pulsating components.     

Contact binaries at different evolutionary stages

Contact binaries consist of two strongly interacting component stars where they are filling their critical Roche lobes and sharing a common envelope. Most of them are main-sequence stars, but some of them are post main-sequence systems. They are good astrophysical laboratories for studying several problems such as the merging of binary stars, evolution of the common envelope, the origin of luminous red nova outbursts and the formation of rapidly rotating single stars with possible planetary systems. A large number of contact binary candidates were detected by several photometric surveys around the world and many of them were observed by the LAMOST spectroscopic survey. Based on follow-up observations,the evolutionary states and geometrical structures of some systems were understood well. In this review,we will introduce and catalog new stellar atmospheric parameters(i.e., the effective temperature(Teff), the gravitational acceleration(log(g)), metallicity([Fe/H]) and radial velocity(Vr)) for 9149 EW-type contact binaries that were obtained based on low-and medium-resolution spectroscopic surveys of LAMOST. Then we will focus on several groups of contact binary stars, i.e., marginal contact binary systems, deep and low-mass ratio contact binary stars, binary systems below the short-period limit of contact binaries and evolved contact binaries. Marginal contact binaries are at the beginning of the contact stage, while deep and low-mass ratio contact binary stars are at the final evolutionary stage of tidally locked binaries. Several statistical relations including the period-temperature relation are determined well by applying LAMOST data and their formation and evolutionary states are reviewed. The period-color relation of M-type binaries reveals that there are contact binaries below the short-period limit. Searching for and investigating contact binaries near and below this limit will help us to understand the formation of contact binary systems and a new prediction for the short-period limit is about 0.15 d. Some evolved contact binaries were detected by the LAMOST survey where both components are sub-giants or giants. They provide a good opportunity to investigate evolution of the common envelope and are the progenitors of luminous red novae like V1309 Sco.     

Circularization of Binary Orbits

In a previous paper Mayer and Hanna (1991) discussed the process of binary orbit circularization for detached eclipsing binaries. An agreement of observational data with Tassoul's circularization time formula for binaries with masses greater than 2.5 M was found. In the present paper we also examine orbital circularization in evolved spectroscopic binaries.     

Absolute physical parameters of three poorly studied detached eclipsing binaries

The photometric and spectroscopic data for three double-lined detached eclipsing binaries were collected from the photometric and spectral surveys.The light and radial velocity curves of each binary system were simultaneously analyzed using Wilson-Devinney(WD)code,and the absolute physical and orbital parameters of these binaries were derived.The masses of both components of ASASSN-V J063123.82+192341.9 were found to be M1=1.088±0.016 and M20.883±0.016 M⊙;those of ASAS J011416+0426.4 were determined to be M1=0.934±0.046 and M2=0.754±0.043 M⊙;and those of MW Aur were derived to be M1=2.052±0.196 and M21.939±0.193 M⊙.Finally,the evolutionary status of these detached binaries was discussed based on their absolute parameters and the theoretical stellar models.     

The data mining: An analysis of 20 eclipsing binary light-curves observed by the INTEGRAL/OMC

Twenty eclipsing binaries were selected for an analysis from a huge database of observations made by the INTEGRAL/OMC camera. The photometric data were processed and analyzed, resulting in a first light-curve study of these neglected eclipsing binaries. Most of the selected systems are the detached ones. The system ET Vel was discovered to be an eccentric one. Due to missing spectroscopic study of these stars, further detailed analyses are still needed.