scholarly journals Notes on Binary Stars: V. The Determination by Least-Squares of the Elements of Spectroscopic Binaries

1941 ◽  
Vol 27 (3) ◽  
pp. 175-181 ◽  
Author(s):  
T. E. Sterne
Keyword(s):  
Least Squares ◽  
Binary Stars ◽  
Spectroscopic Binaries

scholarly journals Physical Parameters and Chemical Composition of Components of the Am-Type Binary System RR Lyncis

1993 ◽  
Vol 138 ◽  
pp. 192-196
Author(s):  
L.S. Lyubimkov ◽  
T.M. Rachkovskaya
Keyword(s):  
Chemical Composition ◽  
Binary System ◽  
Binary Stars ◽  
Spectroscopic Binaries ◽  
Theoretical Modelling ◽  
Physical Parameters ◽  
Accurate Data ◽  
Element Abundances ◽  
Widespread Phenomenon ◽  
Chemical Anomalies

Duplicity is a very widespread phenomenon among Am-stars. For instance, Abt (1961) investigating 25 such stars found out that 22 of them are spectroscopic binaries. However this important phenomenon is ignored usually in chemical composition investigations of Am-stars. Consequently some “mean” element abundances are determined, which can noticeably differ from real abundances in atmospheres of components. Moreover false chemical anomalies can appear, as shown by the theoretical modelling of spectra of binary stars (Lyubimkov, 1989, 1992). Meanwhile accurate data on chemical composition of Am-stars must be considered as observational test for any hypothesis suggested for explanation of these objects.

scholarly journals On the Distribution of Young Spectroscopic Binary Stars Over the Major Semiaxes of their Orbits

1982 ◽  
Vol 69 ◽  
pp. 129-131
Author(s):  
E.I. Popova ◽  
A.V. Tutukov ◽  
B.M. Shustov ◽  
L.R. Yungelson
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Spectroscopic Binaries ◽  
Close Binary ◽  
Physical Parameters ◽  
Origin And Evolution ◽  
Spectroscopic Binary ◽  
Visible Spectra ◽  
Major Semiaxes ◽  
The Masses

About 60% of stars of the disc population in our Galaxy are close binary systems (CBS). Half of the known CBS are spectroscopic binary stars (Kraitcheva et al., 1978).To know the distribution of a correlation between the masses of CBS components and semiaxes of their orbits is necessary for the investigation of the origin and evolution of CBS. For such statistical investigations, a catalogue of CBS was compiled at the Astronomical Council. The catalogue is based on the 6th Batten catalogue (Batten, 1967), its extensions (Pedoussant and Ginestet, 1971; Pedoussant and Carquillat, 1973) and data published up to the end of 1980 (Popova et al., 1981). Now it is recorded on magnetic tape and contains data on 1041 spectroscopic binaries; 333 of them are stars with two visible spectra. The latter are mostly systems prior to mass exchange and the distribution of physical parameters in these systems reflects the distribution and presumably conditions at the time of formation. Using some assumptions, we can obtain for spectroscopic binaries masses of the components M1 and M2 (or the ratio q = M1/M2) and semiaxes of their orbits. Masses of components with the known sin i were obtained by the usual technique; when sin i was not known, masses were estimated from the spectra. We shall discuss here the distribution of CBS in the M-a plane.

scholarly journals Masses of the components of SB2 binaries observed with Gaia – V. Accurate SB2 orbits for 10 binaries and masses of the components of 5 binaries

2020 ◽  
Vol 496 (2) ◽  
pp. 1355-1368
Author(s):  
J-L Halbwachs ◽  
F Kiefer ◽  
Y Lebreton ◽  
H M J Boffin ◽  
F Arenou ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Binary Stars ◽  
Main Sequence ◽  
Spectroscopic Binaries ◽  
Orbital Elements ◽  
Evolved Stars ◽  
The Individual ◽  
The Masses ◽  
Stellar Masses ◽  
Selection Of

ABSTRACT Double-lined spectroscopic binaries (SB2s) are one of the main sources of stellar masses, as additional observations are only needed to give the inclinations of the orbital planes in order to obtain the individual masses of the components. For this reason, we are observing a selection of SB2s using the SOPHIE spectrograph at the Haute-Provence observatory in order to precisely determine their orbital elements. Our objective is to finally obtain masses with an accuracy of the order of one per cent by combining our radial velocity (RV) measurements and the astrometric measurements that will come from the Gaia satellite. We present here the RVs and the re-determined orbits of 10 SB2s. In order to verify the masses, we will derive from Gaia, we obtained interferometric measurements of the ESO VLTI for one of these SB2s. Adding the interferometric or speckle measurements already published by us or by others for four other stars, we finally obtain the masses of the components of five binary stars, with masses ranging from 0.51 to 2.2 solar masses, including main-sequence dwarfs and some more evolved stars whose location in the HR diagram has been estimated.

scholarly journals Sub-Milliarcsecond Optical Astrometry and Binary Stars

1995 ◽  
Vol 166 ◽  
pp. 193-202
Author(s):  
J.T. Armstrong
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Optical Interferometry ◽  
Light Curves ◽  
Spectroscopic Binaries ◽  
Indirect Methods ◽  
Fundamental Parameters ◽  
Long Baseline

Long-baseline optical interferometry has made it possible to measure the visual orbits of binary stars with major axes as small as 5 mas and errors of ≲ 100 μas. Interferometers now nearing completion will extend these values to ≳ 500 μas and σa ∼ 10 μas. Observations of double-lined spectroscopic binaries with current interferometers have already yielded some mass estimates with precisions rivaling those from fitting the light curves of eclipsing double-lined systems. Luminosity estimates based on combined visual interferometric observations and velocity curves are often more precise than those from more indirect methods based on estimates of Teff. New interferometers now coming into operation will make it possible to measure fundamental parameters in dozens to hundreds of binary systems.

scholarly journals Double and Multiple Star Speckle Observations at the 6-m Telescope

1992 ◽  
Vol 135 ◽  
pp. 469-476
Author(s):  
I.I. Balega ◽  
Y.Y. Balega ◽  
V.A. Vasyuk ◽  
J.J. McManus
Keyword(s):  
Binary Stars ◽  
Photon Counting ◽  
Speckle Interferometry ◽  
Spectroscopic Binaries ◽  
Multiple Star ◽  
Stellar Spectra ◽  
Ss 433 ◽  
Composite Spectra ◽  
Wide Range ◽  
Single Aperture

During the last 15 years more than 9,000 speckle interferometric measurements of binary stars have been collected using large optical telescopes (McAlister & Hartkopf 1988). Among them a significant contribution to the world speckle data has been made by the 6-m telscope near Zelenchuk. Up to now this instrument provides the maximal spatial resolution for single–aperture telescopes. First speckle images of the binary Capella were recorded at the telescope in 1977 (Balega & Tikhonov 1977), but we spent 5 more years to create special television techniques for photon counting and digital means for image processing before we started the regular interferometric program of binary observations in the wide range of stellar magnitudes. At first, the measurements were conducted in cooperation with French astronomers from the Centre d’Etudes et de Recherches Geodynamiques et Astronomiques using the optical camera and the television detector developed by Blazit et al. (1977). Since 1983 our equipment has been in use. The program of observations was oriented upon the traditional problems of multiple star speckle interferometry:1.Determination of stellar distances and masses for different types of binaries whose orbital elements can be derived. This includes already known fast visual and astrometric pairs with undetermined orbits, spectroscopic binaries that can be resolved directly, and newly discovered interferometric pairs which show fast orbital motion. The main attention was devoted to the late–type dwarfs in the vicinity of the Sun.2.Search for the secondary components whose existence could explain anomalies of stellar spectra or photometry (stars with composite spectra, occultation binaries, etc.)3.Study of unusual binaries (symbiotic stars, binaries with relativistic components, such as SS 433, etc.)

42. Close Binary Stars (Etoiles Binaires Serrees)

1988 ◽  
Vol 20 (01) ◽  
pp. 569-594
Author(s):  
J. Smak ◽  
R.H. Koch ◽  
K.D. Abhyankar ◽  
J. Andersen ◽  
A.H. Batten ◽  
...  
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Spectroscopic Binaries ◽  
Close Binary ◽  
Close Binaries ◽  
Stellar Winds ◽  
Space Instruments ◽  
Close Binary Stars ◽  
Nuclear Burning ◽  
Astronomy And Astrophysics

During the XlXth General Assembly of the IAU in Delhi the number of members of Cotrmission 42 increased to 260. This simply reflects the growing interest and importance of our field. Growing is not only the number of astronomers involved in research on CBS but also the number of papers resulting from that activity. As an example one can quote the numbers of papers listed during the last few years in Sections 117 (Close Binaries), 119 (Eelipsing Binaries), and 120 (Spectroscopic Binaries) of theAstronomy and Astrophysics Abstracts:705(1982), 775(1983), 836(1984), 1080(1985), and 911(1986); note that many additional references could be added to these numbers from other sections. Naturally, such numbers alone do not reflect the quality and even less so the position and significance of the CBS field. Here one could perhaps mention an impressive record of successful research proposals involving requests for the observing time on large, ground based telescopes and on space instruments. Indeed, in spite of a very strong competition from other fields, programs involving CBS are usually placed very high on the priority lists (cf. Sections 2D and 2E). Obviously, the close binary systems, their evolution, and the physical processes which occur in them (accretion, stellar winds, nuclear burning, etc) appear interesting and important not only to those who are involved in their studies but also to astronomers from other fields.

scholarly journals The nature of the NGC 2546: Not one but two open clusters

2020 ◽  
Vol 633 ◽  
pp. A146 ◽  
Author(s):  
A. D. Alejo ◽  
J. F. González ◽  
M. E. Veramendi
Keyword(s):  
Radial Velocity ◽  
Binary Stars ◽  
Open Cluster ◽  
Open Clusters ◽  
Spectroscopic Binaries ◽  
Physical Parameters ◽  
Distance Modulus ◽  
Cluster Membership ◽  
Spectroscopic Observations ◽  
Astrometric Data

Context. As part of a broader project on the role of binary stars in clusters, we present a spectroscopic study of the open cluster NGC 2546, which is a large cluster lacking previous spectroscopic analysis. Aims. We report the finding of two open clusters in the region of NGC 2546. For the two star groups, we determine radial velocity, parallax, proper motion, reddening, distance modulus, and age, using our spectroscopic observations and available photometric and astrometric data, mainly from the second Gaia data release (Gaia-DR2). We also determine the orbit of four spectroscopic binaries in these open clusters. Methods. From mid-resolution spectroscopic observations for 28 stars in the NGC 2546 region, we determined radial velocities and evaluate velocity variability. To analyze double-lined spectroscopic binaries, we used a spectral separation technique and fit the spectroscopic orbits using a least-squares code. The presence of two stellar groups is suggested by the radial velocity distribution and confirmed by available photometric and astrometric data. We applied a multi-criteria analysis to determine cluster membership, and obtained kinematic and physical parameters of the clusters. Results. NGC 2546 is actually two clusters, NGC 2546A and NGC 2546B, which are not physically related to each other. NGC 2546A has an age of about 180 Myr and a distance of 950 pc. It has a half-number radius of 8 pc and contains about 480 members brighter than G = 18 mag. NGC 2546B is a very young cluster (<10 Myr) located at a distance of 1450 pc. It is a small cluster with 80 members and a half-number radius of 1.6 pc. Stars less massive than 2.5 M⊙ in this cluster would be pre-main-sequence objects. We detected four spectroscopic binaries and determined their orbits. The two binaries of NGC 2546A contain chemically peculiar components: HD 68693 is composed of two mercury-manganese stars and HD 68624 has a Bp silicon secondary. Among the most massive objects of NGC 2546B, there are two binary stars: HD 68572, with P = 124.2 d, and CD -37 4344 with P = 10.4 d.

scholarly journals Statistical Properties of Solar-Type Close Binaries

2004 ◽  
Vol 191 ◽  
pp. 20-27
Author(s):  
J.-L. Halbwachs ◽  
M. Mayor ◽  
S. Udry ◽  
F. Arenou
Keyword(s):  
Binary Stars ◽  
Equal Mass ◽  
Open Clusters ◽  
Statistical Properties ◽  
Spectroscopic Binaries ◽  
Close Binary ◽  
Close Binaries ◽  
Multiple Systems ◽  
Short Period ◽  
Mass Ratios

AbstractTwo Coravel radial velocity surveys dedicated to F7-K field dwarfs and to open clusters are merged in order to investigate the statistical properties of binaries with periods up to 10 years. Thanks to the accurate trigonometric parallaxes provided by Hipparcos, an unbiased sample of spectroscopic binaries (SB) is selected. After correction for the uncertainties of the measurements, the following results are obtained: 1. The distribution of mass ratios exhibits a peak for equal-mass binaries (twins), which is higher for short-period binaries than for long-period binaries. 2. Apart from the twins, the distribution of mass ratios exhibits a broad peak from 0.2 to 0.6. 3. The orbital eccentricities of twins are slightly smaller than those of other binaries. 4. An excess of SB is observed with periods shorter than about 50 days in comparison with the Duquennoy and Mayor log-normal distribution of periods. These features suggest that close binary stars are generated by two different processes. A possible difference could come from the accretion onto the binary, for instance from a common envelope or from a circumbinary disk. Alternatively, twins could come from dynamic evolution of multiple systems. It is not clear whether the formation models are already sufficiently elaborated to reproduce our statistics.

scholarly journals 42. Close Binary Stars (Etoiles Binaires Serrees)

1991 ◽  
Vol 21 (1) ◽  
pp. 479-504 ◽  
Author(s):  
Robert H. Koch
Keyword(s):  
Binary Stars ◽  
Eclipsing Binaries ◽  
Spectroscopic Binaries ◽  
Close Binary ◽  
Close Binaries ◽  
Draft Report ◽  
New Members ◽  
Close Binary Stars ◽  
Personal Appreciation ◽  
Mean Trend

By the end of the XXth General Assembly in Baltimore, the number of Commission 42 members had increased to 305. Subsequently, D. Ya. Martynov has died and 11 new members have been added.The last Draft Report showed a healthy rate of growth in citations of Sections 117 (Close Binaries), 119 (Eclipsing Binaries), and 120 (Spectroscopic Binaries) of Astronomy and Astrophysics Abstracts from 1982 through 1986. The number of these citations has continued the mean trend with 976 and 1015 references for 1987 and 1988, respectively. As the Past-President remarked, these counts are considerable underestimates of the total literature concerning close binaries (hereafter, CB’s). A personal appreciation of the total corpus of work is that quality remains very high and content has become much richer as more and more associations have been made with generalized stellar studies. In part, this may be traced to the everincreasing awareness by the general community of the experiments in stellar evolution which Nature runs in CB’s.

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