scholarly journals Eclipsing Spectroscopic Binaries in the SMC

2005 ◽  
Vol 13 ◽  
pp. 455-455 ◽  
Author(s):  
Ron W. Hilditch ◽  
Tim J. Harries ◽  
Ian D. Howarth
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Binary Star ◽  
Theoretical Models ◽  
Eclipsing Binaries ◽  
Spectroscopic Binaries ◽  
Close Binary ◽  
Exchange Processes ◽  
The Mean ◽  
Close Binary Star

The OGLE survey of the SMC has discovered ~1500 eclipsing binaries thereby providing an excellent platform to study the evolution of close binary systems through case A and case B mass-exchange processes. The complementary spectroscopic radial-velocity studies of these binaries are now in progress and are revealing many interesting systems which challenge current theoretical models of close binary star evolution. These studies also provide excellent direct determinations of distances to these binary stars leading to an improved understanding of the mean distance to the SMC and its 3-D structure. Comparisons between these binary-star distances and other methods of determining the mean distance to the SMC will also be made.

scholarly journals The Eclipses of the Close Binary Star BE UMa

1996 ◽  
Vol 158 ◽  
pp. 471-472
Author(s):  
Janet H. Wood ◽  
E. L. Robinson ◽  
E.-H. Zhang
Keyword(s):  
Light Curve ◽  
High Speed ◽  
Binary Star ◽  
Light Curves ◽  
Close Binary ◽  
Primary Star ◽  
Secondary Star ◽  
Different Depths ◽  
The Mean ◽  
Close Binary Star

BE UMa is a close binary star, not transferring mass, with an extremely hot primary star irradiating the inner face of the cool secondary star. The light curve shows a large-amplitude, sinusoidal variation with a period of 2.29 d, and an eclipse that is centered on the minimum of the variation [1], [3]. According to [1], the eclipse is partial, not total. However, it has been argued [2] that the eclipse was really flat bottomed and thus total. This has important repercussions for the deduced model of the system. To resolve this issue we obtained simultaneous UBVR photometry of BE UMa using the Stiening 4-channel, high-speed photometer on the 82-inch telescope at McDonald Observatory. The mean light curves are shown in Fig. 1. The eclipse in all colours is round bottomed and partial. The different depths are caused by the different contribution from the red secondary star in each bandpass.

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 Discovery and characterisation of long-period eclipsing binary stars from Kepler K2 campaigns 1, 2, and 3

2018 ◽  
Vol 616 ◽  
pp. A38 ◽  
Author(s):  
P. F. L. Maxted ◽  
R. J. Hutcheon
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Binary Star ◽  
Eclipsing Binaries ◽  
Star Model ◽  
Eclipsing Binary ◽  
Giant Stars ◽  
Long Period ◽  
Eclipsing Binary Stars

Context. The Kepler K2 mission now makes it possible to find and study a wider variety of eclipsing binary stars than has been possible to-date, particularly long-period systems with narrow eclipses. Aims. Our aim is to characterise eclipsing binary stars observed by the Kepler K2 mission with orbital periods longer than P ≈ 5.5 days. Methods. The ellc binary star model has been used to determine the geometry of eclipsing binary systems in Kepler K2 campaigns 1, 2 and 3. The nature of the stars in each binary is estimated by comparison to stellar evolution tracks in the effective temperature – mean stellar density plane. Results. 43 eclipsing binary systems have been identified and 40 of these are characterised in some detail. The majority of these systems are found to be late-type dwarf and sub-giant stars with masses in the range 0.6–1.4 solar masses. We identify two eclipsing binaries containing red giant stars, including one bright system with total eclipses that is ideal for detailed follow-up observations. The bright B3V-type star HD 142883 is found to be an eclipsing binary in a triple star system. We observe a series of frequencies at large multiples of the orbital frequency in BW Aqr that we tentatively identify as tidally induced pulsations in this well-studied eccentric binary system. We find that the faint eclipsing binary EPIC 201160323 shows rapid apsidal motion. Rotational modulation signals are observed in 13 eclipsing systems, the majority of which are found to rotate non-synchronously with their orbits. Conclusions. The K2 mission is a rich source of data that can be used to find long period eclipsing binary stars. These data combined with follow-up observations can be used to precisely measure the masses and radii of stars for which such fundamental data are currently lacking, e.g., sub-giant stars and slowly-rotating low-mass stars.

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 Impact of Large Databases on the Knowledge of Late-Type Close Binaries

2004 ◽  
Vol 191 ◽  
pp. 239-246
Author(s):  
C. Maceroni
Keyword(s):  
Binary Star ◽  
Eclipsing Binaries ◽  
Close Binary ◽  
Close Binaries ◽  
Future Space ◽  
Large Databases ◽  
Interesting Object ◽  
Close Binary Star ◽  
The Impact

AbstractThis paper presents some results of the analysis of the eclipsing binaries samples that came out as by-products of the OGLE microlensing surveys. These experiments monitored millions of stars in the direction of the galactic bulge (OGLE-I), and of the Small Magellanic Cloud (OGLE-II). Their completeness allowed the discovery of rare and interesting systems. An example is a new group of long period binaries in the SMC with presumably a giant component in contact with the critical lobe, which dominates the systemic light variation (“β -contacts”). These systems obey a period-luminosity-color relation and could be used as an auxiliary, but independent, tool for distance determination. Another very interesting object, for its implications in the studies of angular momentum loss processes by magnetic braking and of stellar activity, is the system of shortest known period with M dwarf components, discovered by OGLE-I, BW3 V38, that is the target of a spectroscopic follow-up. The perspectives for close binary star research in view of future space missions, such as COROT and Eddington are briefly discussed.

scholarly journals Asteroseismology of Close Binary Stars: Tides and Mass Transfer

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhao Guo
Keyword(s):  
Mass Transfer ◽  
Binary Stars ◽  
Binary Systems ◽  
Binary Star ◽  
Close Binary ◽  
Close Binaries ◽  
Linear Mode ◽  
Stellar Oscillations ◽  
Theoretical Approaches ◽  
Stellar Interiors

The study of stellar oscillations allows us to infer the properties of stellar interiors. Meanwhile, fundamental parameters such as mass and radius can be obtained by studying stars in binary systems. The synergy between binarity and asteroseismology can constrain the parameter space of stellar properties and facilitate the asteroseismic inference. On the other hand, binarity also introduces additional complexities such tides and mass transfer. From an observational perspective, we briefly review the recent advances in the study of tidal effects on stellar oscillations, focusing on upper main sequence stars (F-, A-, or OB- type). The effect can be roughly divided into two categories. The first one concerns the tidally excited oscillations (TEOs) in eccentric binaries where TEOs are mostly due to resonances between dynamical tides and gravity modes of the star. TEOs appear as orbital-harmonic oscillations on top of the eccentric ellipsoidal light curve variations (the “heartbeat” feature). The second category is regarding the self-excited oscillations perturbed by static tides in circularized and synchronized close binaries. It includes the tidal deformation of the propagation cavity and its effect on eigenfrequencies, eigenfunctions, and the pulsation alignment. We list binary systems that show these two types of tidal effect and summarize the orbital and pulsation observables. We also discuss the theoretical approaches used to model these tidal oscillations and relevant complications such as non-linear mode coupling and resonance locking. Further information can be extracted from the observations of these oscillations which will improve our understanding of tides. We also discuss the effect of mass transfer, the extreme result of tides, on stellar oscillations. We bring to the readers' attention: (1) oscillating stars undergoing mass accretion (A-, F-, and OB type pulsators and white dwarfs), for which the pulsation properties may be changed significantly by accretion; (2) post-mass transfer pulsators, which have undergone a stable or unstable Roche-Lobe overflow. These pulsators have great potential in probing detailed physical processes in stellar interiors and mass transfer, as well as in studying the binary star populations.

scholarly journals Mass Transfer Characterization in Close Binary Stars

1992 ◽  
Vol 151 ◽  
pp. 337-340
Author(s):  
J. M. García ◽  
A. Giménez
Keyword(s):  
Mass Transfer ◽  
Angular Momentum ◽  
Binary Stars ◽  
Binary Star ◽  
Type System ◽  
Close Binary ◽  
Select Group ◽  
Close Binary Stars ◽  
Loss Of Mass ◽  
Close Binary Star

A method for estimating representative values of the parameters that characterize the loss of mass and angular momentum occurred during the evolution of a close binary star is considered. Absolute dimensions previous to mass-transfer stage have been obtained for a select group of 43 semidetached systems adopting a grid of values of mass loss, angular momentum loss and initial mass ratio. Our study reveals a highly non-conservative scenario for the evolution towards an Algol-type system.

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.

scholarly journals New distance and depth estimates from observations of eclipsing binaries in the SMC

2008 ◽  
Vol 4 (S256) ◽  
pp. 57-62
Author(s):  
Pierre L. North ◽  
Romain Gauderon ◽  
Frédéric Royer
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Average Error ◽  
Distance Modulus ◽  
Orbital Parameters ◽  
Individual System ◽  
The Mean

AbstractA sample of 33 eclipsing binaries observed in a field of the SMC with FLAMES@VLT is presented. The radial velocity curves obtained, together with existing OGLE light curves, allowed the determination of all stellar and orbital parameters of these binary systems. The mean distance modulus of the observed part of the SMC is 19.05 mag, based on the 26 most reliable systems. Assuming an average error of 0.1 mag on the distance modulus to an individual system, and a gaussian distribution of the distance moduli, we obtain a 2-σ depth of 0.36 mag or 10.6 kpc. Some results on the kinematics of the binary stars and of the H ii gas are also given.

scholarly journals Interferometric measurements of binaries

1997 ◽  
Vol 189 ◽  
pp. 109-114
Author(s):  
H.A. McAlister
Keyword(s):  
Binary Stars ◽  
Binary Star ◽  
Center Of Mass ◽  
Angular Separation ◽  
Eclipsing Binaries ◽  
Spectroscopic Binaries ◽  
Past Performance ◽  
Short Period ◽  
Stellar Masses

This paper is a brief overview of the past performance and future promise of interferometry as applied to the study of binary stars. For the sake of brevity, the important results from infrared techniques in recent years are regretfully omitted here. It is probably unnecessary to remind the reader that the analysis of binary star orbital motions is the only direct means for the determination of stellar masses. Historically, stellar masses have resulted primarily from orbits that are sufficiently wide in angular separation to permit the astrometric determination of the motions of the individual components about the center of mass as well as the parallax of the system or from short-period spectroscopic/eclipsing binaries. The advent of long baseline optical interferometers holds the promise of a wealth of new stellar mass data through the direct resolution of spectroscopic binaries.

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