scholarly journals Rotational Properties and Synchronization in Early-Type Close Binaries

1985 ◽  
Vol 111 ◽  
pp. 401-402
Author(s):  
G. Giuricin ◽  
F. Mardirossian ◽  
M. Mezzetti
Keyword(s):  
Angular Velocity ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Spectroscopic Binaries ◽  
Close Binaries ◽  
Early Type ◽  
Orbital Inclination ◽  
Eccentric Orbits ◽  
The Mean ◽  
The Absolute

We have rediscussed the synchronism between rotation and revolution in close binaries by an inspection of the published projected rotational velocities V sin i of about 250 early-type (from 0 to F5) eclipsing and double-lined spectroscopic binaries. Corrections of the V sin i - values (which are mainly taken from the catalog of Uesugi and Fukuda, 1982) for the aspect effect is straightforward for the eclipsing binaries with analyzed light-curves; in the other cases we have estimated the value of the orbital inclination angle i from the primary's minimum mass M1 sin3 i on the assumption that its mass follows Straižys and Kuriliené's (1981) mass-spectrum relations for different luminosity classes. For the components of non-eclipsing binaries, for which the absolute radii are not directly known, we have adopted values of the absolute radii in accordance with Straižys and Kuriliené's (1981) radius-spectrum relations for different luminosity classes. By using our estimates of the radii, for each component we have evaluated the synchronized velocity Vk (corresponding to the mean orbital angular velocity) and the pseudosynchronized velocity Ve, which corresponds to a synchronization with the instantaneous orbital angular velocity at periastron of an eccentric orbit; in close binaries with appreciably eccentric orbits synchronization is attained with V/Vk>1 and it is probably quickly reached at periastron (Hut 1981).

scholarly journals Starspot migration in close binaries: A fast parameters evaluation from large sky surveys

2016 ◽  
Vol 12 (S325) ◽  
pp. 274-277
Author(s):  
B. Debski ◽  
S. Zola
Keyword(s):  
Visual Inspection ◽  
Magnetic Activity ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Close Binaries ◽  
Intrinsic Variability ◽  
Sky Surveys ◽  
Orbital Periods

AbstractWe developed a method that allows to classify the light curves of eclipsing binaries of the W UMa type (EW) with respect to their intrinsic variability. The algorithm measures several features of light curves, such as the amplitude of the O’Connell effect, the separation and location of maxima brightness as well as depths of the minima in subsequent orbital periods. This method is capable of distinguishing systems with presumed magnetic activity present from these without it, as well as recognizing systems with starspots migration and those with other types of intrinsic variability manifestation. The classification is done in an automatic way without a time consuming, visual inspection of light curves.

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 Seeing Double in the Local Group: Extragalactic Binaries

2005 ◽  
Vol 13 ◽  
pp. 446-446
Author(s):  
Edward F. Guinan
Keyword(s):  
Binary Systems ◽  
Local Group ◽  
Magellanic Clouds ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Close Binaries ◽  
Major Advance ◽  
Future Expectations ◽  
High Quantum ◽  
Orbital Periods

Photographic surveys of the Magellanic Clouds and the M31 carried decades ago discovered ~200 close binaries. In most cases the photographic light curves are good enough only to identify the stars as close (mostly eclipsing) binaries and to estimate orbital periods and binary type. Except for a few cases, little useful information may be obtained from these stars except to be reassured that eclipsing binary (EB) systems are present in other galaxies. However a major advance occurred with the advent of high quantum efficient CCDs. Because of this an explosion in the number of known extragalactic binaries occurred during the 1990s as offshoots of photometric microlensing surveys such as EROS, MACHO, and OGLE. Now over 10 000 extragalactic EBs have been identified. Also, photometric surveys of M31 and M33 (e.g. DIRECT) are discovering many more 19-20th mag eclipsing/close binaries. Over the next decade it is expected that ~1 million new binary systems will be identified in these galaxies. In this overview I will discuss recent advances and future expectations in the studies of extragalactic binaries

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 CHALLENGES OF MODELLING THE ACTIVITIES OCCURRING ON ECLIPSING BINARIES V1130 CYG AND V461 LYR

2021 ◽  
Vol 57 (2) ◽  
pp. 335-349
Author(s):  
E. Yoldaş ◽  
H. A. Dal
Keyword(s):  
Eclipsing Binaries ◽  
Light Curves ◽  
Secondary Component ◽  
Mass Ratio ◽  
Orbital Inclination ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

We present the findings for the magnetic activities seen on V1130 Cyg and V461 Lyr. In the case of V1130 Cyg, the secondary component's temperature was found to be 3891±50 K, while the mass ratio was computed as 0.689±0.001, and the orbital inclination as 90°.00±0°.01. The temperature of V461 Lyr's secondary component was found to be 4206±50 K, and the mass ratio was calculated as 0.999±0.001 with 89°.58±0°.01 of orbital inclination. The analyses exhibit the effects of the stellar spots on the light curves. The models indicate that there are two types of flares in the case of V1130 Cyg, and three types of flares for V461 Lyr. The Plateau parameters have been found as 2.1997 s for Group 1 and 1.0068 s for Group 2 in the case of V1130 Lyr. They have been computed as 1.9015 s for Group 1, 2.7943 s for Group 2, and 3.4324 s for Group 3 of V461 Lyr.

scholarly journals The asymmetric light curves of the GSC 2764 1417 (And), GSC 3355 0394 (Per) and GSC 2537 0520 (Psc)

2009 ◽  
Vol 5 (S264) ◽  
pp. 75-77
Author(s):  
Ronald G. Samec ◽  
Evan R. Figg ◽  
Reid Melton ◽  
Christa M. Labadorf ◽  
Jess Miller ◽  
...  
Keyword(s):  
Eclipsing Binaries ◽  
Light Curves ◽  
Close Binaries ◽  
Short Period ◽  
Solar Type

AbstractSolar-type variability is enhanced in short period close binaries with increased dynamo driven activity. This activity is studied in our analysis of recent light curves taken of the newly discovered eclipsing binaries GSC 2764 1417 (And), GSC 3355 0394 (Per) and GSC 2537 0775 (CVn).

scholarly journals Statistical Investigation of Physical and Geometrical Parameters in Close Binaries using the ASAS Database

2011 ◽  
Vol 7 (S282) ◽  
pp. 73-74 ◽  
Author(s):  
J. Nedoroščik ◽  
M. Vaňko ◽  
Š. Parimucha
Keyword(s):  
Light Curve ◽  
Fourier Coefficients ◽  
Variable Stars ◽  
Statistical Investigation ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Close Binaries ◽  
Geometrical Parameters ◽  
Statistical Research ◽  
Pulsating Variable Stars

AbstractThe main goal of this work was to find dependencies between Fourier coefficients, which were developed by light curve fitting with Fourier polynomials. The light curves were acquired from the ASAS database (All Sky Automated Survey). In this statistical research it was necessary to sort and modify these data, because light curves of eclipsing binaries are just part of a bigger database, which contains the light curves of pulsating variable stars, novas etc. It was required to phase and normalize all of our light curves, that it could be possible to use a program to fit light curves with Fourier coefficients. Thereafter, we were looking for relations between Fourier coefficients.

scholarly journals Absolute Dimensions and Distance Modulus for HV 2226 in the SMC

1992 ◽  
Vol 151 ◽  
pp. 501-504
Author(s):  
S.A. Bell ◽  
G. Hill ◽  
R.W. Hilditch ◽  
J.V. Clausen ◽  
A.P. Reynolds ◽  
...  
Keyword(s):  
Mass Transfer Process ◽  
Yield Component ◽  
Radial Velocities ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Distance Modulus ◽  
Early Type ◽  
Effective Temperatures ◽  
Distance Indicators ◽  
Absolute Dimensions

Absolute dimensions and the distance modulus have been established for the early-type eclipsing binary HV 2226 in the SMC. Analyses of the new radial velocities reported here, and CCD light curves published by Jensen et al. (1988) yield component masses of 9.3 ± 0.7 and 5.6 ± 0.5 M⊙, respectively. The radii are 5.6 ± 0.2 and 5.3 ± 0.2 R⊙ with the secondary component filling its Roche lobe which implies that HV 2226 must have evolved through a case A mass-transfer process. A distance modulus of (mv – Mv)0 = 18m.6 ± 0m.3 is derived, marginally lower than the adopted mean of 18m.9 for the SMC. The position of HV 2226, however, indicates that it is in fact situated in the near side of the SMC. In the present case, the accuracy of this estimate is limited mainly by the uncertainties of ≈ 2000 K in the effective temperatures. We point out that distance moduli with uncertainties of ± 0m.15 can be achieved from accurate radial velocities, light curves and colour indices of eclipsing binaries; such systems in the SMC and LMC are therefore promising distance indicators and work on further selected candidates is in progress.

scholarly journals Statistical analysis of period-eccentricity distribution for large samples of close binaries from Kepler, CoRoT and SB9 databases

2019 ◽  
Vol 82 ◽  
pp. 127-133
Author(s):  
J. Sztakovics ◽  
E. Forgács-Dajka ◽  
T. Borkovits ◽  
T. Hajdu ◽  
G. Marschalkó
Keyword(s):  
Statistical Analysis ◽  
Space Missions ◽  
Double Star ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Close Binaries ◽  
Large Samples ◽  
Dynamical Parameters ◽  
The Difference

Period–eccentricity distribution of eccentric eclipsing binaries (eEB) has inevitable importance in the study of the different kinds of tidal circularization (and synchronization) processes. Recent space missions provide a large amount of continuous and precise light curves, which enable us to determine several accurate stellar and dynamical parameters for thousands of freshly discovered eEBs. For statistical analysis we developed a fast, automated, although approximating method for determining eccentricity and argument of periastron from the displacement of the secondary minima and the difference of primary and secondary eclipse durations for large samples of eclipsing lightcurves. Applying this method to several hundreds of recently discovered eEBs in the fields of the primordial and secondary Kepler and also the CoRoT missions, we present a comprehensive statistical analysis of the period–eccentricity relation for different subgroups of these double star systems.

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