scholarly journals Binary Star Observations in Selected Instants of Good Seeing

2001 ◽  
Vol 18 (3) ◽  
pp. 281-286 ◽  
Author(s):  
John Davis ◽  
Julian R. North
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Binary Star ◽  
Coherence Time ◽  
Diffraction Limit ◽  
Video Recordings ◽  
Comparable Accuracy ◽  
Magnitude Difference ◽  
Good Agreement

AbstractVideo recordings of images of binary stars at the focus of a 0.36m telescope have been used to select images recorded in instants of good seeing. The selected images have been analysed to give separations and position angles for the binary systems which are in good agreement with values predicted from previous observations. In these exploratory observations it has been shown that separations of 0.9 arcseconds can be measured with an accuracy of ~2% and position angles to ~1–2 degrees when the average seeing was ~1.3 arcseconds. These observations demonstrated that the diffraction limit of the telescope could be reached when the seeing was a factor of 2–3 greater than it. A binary with three magnitudes difference in the brightness of its components has been measured with comparable accuracy although difficulties are anticipated for binaries with components closer than ~2 arcseconds with this magnitude difference. The limiting magnitude is determined by the need to limit exposure times of individual frames to be comparable with or less than the atmospheric coherence time.

scholarly journals Speckle Observations of Binary Stars with the MAMA Detector

1992 ◽  
Vol 135 ◽  
pp. 549-551
Author(s):  
E. Horch ◽  
J.S. Morgan ◽  
G. Giaretta ◽  
John G. Timothy ◽  
D.B. Kasle
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Arrival Time ◽  
Photon Counting ◽  
Diffraction Limit ◽  
Image Features ◽  
Future Prospects ◽  
Imaging Device ◽  
Microchannel Array ◽  
Magnitude Difference

AbstractWe have made two sets of speckle observations of binary stars with the Multi-Anode Microchannel Array (MAMA) detector. Our observing system is a true photon counting imaging device which records the arrival time of every detected photon. We present speckle autocorrelation analyses of five binary systems, two observed with the 3.6-m telescope at the European Southern Observatory and three observed with the 40-in reflector at Lick Observatory. These five systems represent a wide variation in separation and magnitude difference that indicate that the MAMA detector is capable of recording high quality speckle data at extremely low count rates and can recover image features very near the diffraction limit of the telescope. In one case, only 10 photons per frame were recorded for the dim companion of the system, and in another case, a separation of 0″.157±0″.031 was derived for a system observed with the 40-in telescope where the diffraction limit is about 0″.125. Future prospects for this system are discussed.

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.

scholarly journals Origin of the orbital period change in contact binary stars

2019 ◽  
Vol 28 (06) ◽  
pp. 1950044 ◽  
Author(s):  
V. V. Sargsyan ◽  
H. Lenske ◽  
G. G. Adamian ◽  
N. V. Antonenko
Keyword(s):  
Orbital Period ◽  
Binary Stars ◽  
Binary Systems ◽  
Binary Star ◽  
Period Change ◽  
Mass Asymmetry ◽  
Contact Binary Stars ◽  
Contact Binary ◽  
Energy Formula ◽  
Orbital Periods

The evolution of contact binary star systems in mass asymmetry (transfer) coordinate is considered. The orbital period changes are explained by an evolution in mass asymmetry towards the symmetry (symmetrization of binary system). It is predicted that decreasing and increasing orbital periods are related, respectively, with the nonoverlapping and overlapping stage of the binary star during its symmetrization. A huge amount of energy [Formula: see text][Formula: see text]J is converted from the potential energy into internal energy of the stars during the symmetrization. As shown, the merger of stars in the binary systems, including KIC 9832227, is energetically an unfavorable process. The sensitivity of the calculated results to the values of total mass and orbital angular momentum is analyzed.

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 Polarimetry of Binary Stars and Exoplanets

2011 ◽  
Vol 7 (S282) ◽  
pp. 173-180
Author(s):  
Karen S. Bjorkman
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Binary Star ◽  
Orbital Inclination ◽  
Orbital Parameters ◽  
Circumstellar Environments ◽  
Exoplanet Systems

AbstractPolarimetry is a useful diagnostic of asymmetries in both circumstellar environments and binary star systems. Its sensitivity to asymmetries in systems means that it can help to uncover details about system orbital parameters, including providing information about the orbital inclination. Polarimetry can probe the circumstellar and/or circumbinary material as well. A number of significant results on binary systems have been produced by polarimetric studies. One might therefore expect that polarimetry could similarly play a useful role in studies of exoplanets, and a number of possible diagnostics for exoplanets have been proposed. However, the application of polarimetry to exoplanet research is only in preliminary stages, and the difficulties with applying the technique to exoplanets are non-trivial. This review will discuss the successes of polarimetry in analyzing binary systems, and consider the possibilities and challenges for extending similar analysis to exoplanet systems.

Application of a probabilistic neural network in radial velocity curve analysis of the spectroscopic binary stars PV Pup, BV Dra, AI Phe, V1130 Tau, NSV 223, and V502 Oph

2011 ◽  
Vol 89 (10) ◽  
pp. 1035-1040 ◽  
Author(s):  
K. Karami ◽  
K. Ghaderi ◽  
R. Mohebi ◽  
M.M. Soltanzadeh
Keyword(s):  
Radial Velocity ◽  
Binary Stars ◽  
Binary Systems ◽  
Probabilistic Neural Network ◽  
Curve Analysis ◽  
Velocity Data ◽  
Radial Velocity Curve ◽  
Spectroscopic Binary ◽  
Radial Velocity Data ◽  
Good Agreement

Using measured radial velocity data from six double-lined spectroscopic binary systems PV Pup, BV Dra, AI Phe, V1130 Tau, NSV 223 (or DZ Psc), and V502 Oph, we find corresponding orbital and spectroscopic elements via the method introduced by Karami et al. (New Astron. 14, 478 (2009)). Our numerical results are in good agreement with those obtained by others using more traditional methods. Using a statistical analysis, we also conclude that for BV Dra, V1130 Tau, NSV 223 (or DZ Psc), and V502 Oph, a circular orbit is quite consistent.

scholarly journals Velocity-Curve Analysis of the Spectroscopic Binary Stars V373 Cas, V2388 Oph, V401 Cyg, GM Dra, V523 Cas, AB And and HD 141929 by Artificial Neural Networks

2009 ◽  
Vol 26 (2) ◽  
pp. 121-127 ◽  
Author(s):  
K. Karami ◽  
K. Ghaderi ◽  
R. Mohebi ◽  
R. Sadeghi ◽  
M. M. Soltanzadeh
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Curve Analysis ◽  
Velocity Data ◽  
Orbital Parameters ◽  
Spectroscopic Binary ◽  
Artificial Neural ◽  
Artificial Neural Network Ann ◽  
Radial Velocity Data ◽  
Good Agreement

AbstractWe used an Artificial Neural Network (ANN) to derive the orbital parameters of spectroscopic binary stars. Using measured radial velocity data of seven double-lined spectroscopic binary systems V373 Cas, V2388 Oph, V401 Cyg, GM Dra, V523 Cas, AB And and HD 141929, we found corresponding orbital and spectroscopic elements. Our numerical results are in good agreement with those obtained by others using more traditional methods.

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 Binary Systems as X-Ray Sources: A Review

1973 ◽  
Vol 55 ◽  
pp. 36-50 ◽  
Author(s):  
Robert P. Kraft
Keyword(s):  
Mass Transfer ◽  
Boundary Conditions ◽  
Binary Stars ◽  
Binary Systems ◽  
Binary Star ◽  
Gravitational Energy ◽  
Evolutionary Models ◽  
Evolutionary Mechanisms ◽  
X Ray ◽  
The Galaxy

The observational properties of Sco X-1, Cyg X-2, and Cen X-3 are reviewed in connection with the hypothesis that X-ray power is derived from gravitational energy released when matter is accreted onto the surface of one component in a mass transfer binary star. Evolutionary mechanisms for producing suitable types of binaries are considered. The following boundary conditions on possible evolutionary models are also treated briefly: (1) a quite significant fraction of hard X-ray sources are associated with the nuclear bulge of the galaxy; (2) mass-transfer binaries such as U Gem stars are not hard X-ray sources; (3) counts of binary stars lead to a considerably larger number of X-ray source candidates than are actually observed.

scholarly journals Binary Stars: Historical Milestones

2001 ◽  
Vol 200 ◽  
pp. 1-12 ◽  
Author(s):  
Hans Zinnecker
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Binary Star ◽  
Historical Review ◽  
History Of Ideas ◽  
Double Stars ◽  
Spectroscopic Binary ◽  
History Of ◽  
Statistical Argument ◽  
Definition Of

This is a brief historical review of the discovery of binary stars, starting in the 18th and 19th century with the work of W. Herschel, W. Struve, and their famous sons. I describe how Ch. Doppler in 1842 found the Doppler effect in connection with the colours of double stars. I also describe how the observation of the stationary Calcium H and K lines in the spectrum of the spectroscopic binary δ Ori led to the discovery of the interstellar medium by J. Hartmann in 1904 with the Potsdam refractor. Some steps in the discovery of young binary stars are recounted, starting with the paper of Joy and van Biesbroeck in 1944. The history of ideas regarding the origin of binary systems is also briefly reviewed, beginning with J. Michell's statistical argument in 1767 that many close visual pairs of stars must indeed form physical systems, and W. Herschel's definition of a binary star as “a real double star - the union of two stars that are formed together in one system, by the laws of attraction”.

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