scholarly journals Physical Parameters of Late-type Contact Binaries in the Northern Catalina Sky Survey

2020 ◽  
Vol 247 (2) ◽  
pp. 50 ◽  
Author(s):  
Weijia Sun ◽  
Xiaodian Chen ◽  
Licai Deng ◽  
Richard de Grijs
Keyword(s):  
Physical Parameters ◽  
Late Type ◽  
Sky Survey ◽  
Type Contact ◽  
Contact Binaries

scholarly journals Surface Imaging of Late-Type Contact Binaries II: Hα Emission in AE Phe and YY Eri

2006 ◽  
Vol 2 (S240) ◽  
pp. 719-723
Author(s):  
O. Vilhu ◽  
C. Maceroni
Keyword(s):  
Active Component ◽  
Theoretical Models ◽  
Surface Imaging ◽  
Late Type ◽  
Saturation Limit ◽  
Chromospheric Activity ◽  
Type Contact ◽  
Contact Binaries ◽  
Hα Emission

AbstractWe present and discuss the Hα (λ = 6563Å) observations of the contact (W UMa type) binaries AE Phoenicis and YY Eridani, obtained in 1989, 1990 and 1995 with the CAT/CES telescope of the Southern European Observatory (ESO). In particular, we compare the intrinsic equivalent widths of both components with the NextGen theoretical models and the saturation limit. We find that the average Hα equivalent widths are close to the saturation border and that the primary components have excess Hα-emission, indicating enhanced chromospheric activity. This is compatible with both theoretical and observational suggestions that the primary is the more magnetically active component and is filled with (mostly unresolvable) dark spots and associated chromospheric plages.

scholarly journals Zwicky Transient Facility and Globular Clusters: the Period–Luminosity and Period–Luminosity–Color Relations for Late-type Contact Binaries

2021 ◽  
Vol 162 (2) ◽  
pp. 63
Author(s):  
Chow-Choong Ngeow ◽  
Szu-Han Liao ◽  
Eric C. Bellm ◽  
Dmitry A. Duev ◽  
Matthew J. Graham ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Late Type ◽  
Type Contact ◽  
Contact Binaries

Orbital period cut-off of W UMa-type contact binaries

2020 ◽  
Vol 497 (3) ◽  
pp. 3493-3503 ◽  
Author(s):  
Xu-Dong Zhang ◽  
Sheng-Bang Qian
Keyword(s):  
Orbital Period ◽  
Physical Parameters ◽  
Mass Ratio ◽  
Primary Star ◽  
The Past ◽  
Type Contact ◽  
Contact Binaries ◽  
Theoretical Mechanism ◽  
Orbital Periods ◽  
Comprehensive Study

ABSTRACT Period cut-off and period–colour relation are two special characters of W UMa-type contact binaries. In the past, many authors noted these two properties, however, a comprehensive study was still lacking. In order to reveal a theoretical mechanism behind these two peculiarities, we collected 365 contact binaries whose orbital periods, mass ratios, masses, and radii are compiled and attempted to make this idea come true by statistical means. Then, we obtained a lower limit (0.15 d) of orbital period by studying the correlation among four physical parameters (orbital period P, mass ratio q, mass of primary star M1, and separation between two components a). Furthermore, we used the most reliable parameters (P and q) to check our result, fortunately, all evidence indicated that our predicted value is credible. In the end, the reason why the period–colour relation exists was also discussed.

scholarly journals A hundred new eclipsing binary system candidates studied in a near-infrared window in the VVV survey

2020 ◽  
Vol 37 ◽  
Author(s):  
L. V. Gramajo ◽  
T. Palma ◽  
D. Minniti ◽  
R. K. Saito ◽  
J. J. Clariá ◽  
...  
Keyword(s):  
Near Infrared ◽  
Galactic Disk ◽  
Extensive Study ◽  
Eclipsing Binaries ◽  
Physical Parameters ◽  
Eclipsing Binary ◽  
Mean Values ◽  
Median Period ◽  
First Results ◽  
Contact Binaries

Abstract We present the first results obtained from an extensive study of eclipsing binary (EB) system candidates recently detected in the VISTA Variables in the Vía Láctea (VVV) near-infrared (NIR) Survey. We analyse the VVV tile d040 in the southern part of the Galactic disc wherein the interstellar reddening is comparatively low, which makes it possible to detect hundreds of new EB candidates. We present here the light curves and the determination of the geometric and physical parameters of the best candidates found in this ‘NIR window’, including 37 contact, 50 detached, and 13 semi-detached EB systems. We infer that the studied systems have an average of the $K_s$ amplitudes of $0.8$ mag and a median period of 1.22 days where, in general, contact binaries have shorter periods. Using the ‘Physics Of Eclipsing Binaries’ (PHOEBE) interactive interface, which is based on the Wilson and Devinney code, we find that the studied systems have low eccentricities. The studied EBs present mean values of about 5 700 and 4 900 K for the $T_1$ and $T_2$ components, respectively. The mean mass ratio (q) for the contact EB stars is $\sim$ 0.44. This new galactic disk sample is a first look at the massive study of NIR EB systems.

scholarly journals SuperWASP variable stars: classifying light curves using citizen science

2021 ◽  
Vol 502 (1) ◽  
pp. 1299-1311
Author(s):  
Heidi B Thiemann ◽  
Andrew J Norton ◽  
Hugh J Dickinson ◽  
Adam McMaster ◽  
Ulrich C Kolb
Keyword(s):  
Variable Stars ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Data Set ◽  
Resultant Data ◽  
Sky Survey ◽  
Short Period ◽  
Contact Binaries ◽  
Analysis Of Results

ABSTRACT We present the first analysis of results from the SuperWASP variable stars Zooniverse project, which is aiming to classify 1.6 million phase-folded light curves of candidate stellar variables observed by the SuperWASP all sky survey with periods detected in the SuperWASP periodicity catalogue. The resultant data set currently contains >1 million classifications corresponding to >500 000 object–period combinations, provided by citizen–scientist volunteers. Volunteer-classified light curves have ∼89 per cent accuracy for detached and semidetached eclipsing binaries, but only ∼9 per cent accuracy for rotationally modulated variables, based on known objects. We demonstrate that this Zooniverse project will be valuable for both population studies of individual variable types and the identification of stellar variables for follow-up. We present preliminary findings on various unique and extreme variables in this analysis, including long-period contact binaries and binaries near the short-period cut-off, and we identify 301 previously unknown binaries and pulsators. We are now in the process of developing a web portal to enable other researchers to access the outputs of the SuperWASP variable stars project.

scholarly journals Light curve analysis of the late type binary V523 Cassiopeiae

2009 ◽  
pp. 45-48 ◽  
Author(s):  
O. Latkovic ◽  
M. Zboril ◽  
G. Djurasevic
Keyword(s):  
Light Curve ◽  
Monitoring Program ◽  
Neck Region ◽  
Bright Spot ◽  
Late Type ◽  
Light Curve Analysis ◽  
Type Contact ◽  
Contact Binary ◽  
Previous Solution

We present the analysis of V and R light curves of the late type contact binary V523 Cas for the season of 2006. These observations make part of the monitoring program aimed at studying the long-term light curve variability in this system. Our results confirm that the system is in an over contact configuration, and include a bright spot in the neck region of the cooler and larger primary. We compare these results with the previous solution, obtained for the season 2005 dataset and discuss the differences.

scholarly journals By Draconis and RS Canum Venaticorum Stars: The Discoveries of Classical Photometry and Spectroscopy

1980 ◽  
Vol 5 ◽  
pp. 847-848 ◽  
Author(s):  
Bernard W. Bopp
Keyword(s):  
Spectroscopic Binaries ◽  
Physical Parameters ◽  
Late Type ◽  
Double Line ◽  
Strong Emission ◽  
Rs Cvn Stars ◽  
Ceti Type ◽  
The Common ◽  
Orbital Periods ◽  
Detached Binaries

Physically quite dissimilar, the BY Dra and RS CVn stars have the common characteristic of extraordinarily high levels of stellar surface activity.The RS CVn group, as defined by Hall, consists of detached binaries both components of types F, G, or K. The orbital periods are from a few days to a few weeks, and the mass ratios are generally near unity. Spectroscopically, the stars are remarkable in that they show very strong Ca II H and K emission outside eclipse. Masses and radii are known for many of these systems; physical parameters indicate these systems contain a moderately evolved subgiant, with mass slightly greater than 1 M⊚. The ages (which may be verified by data on visual companions) are a few 10 years.In contrast, the BY Dra variables are late-type dwarfs, with spectral types ranging from dK5e to dM4e. The e designation indicates the presence of Balmer emission, which is generally visible in moderate strength at Ha and only very weakly present in the blue. The BY Dra stars do exhibit strong emission at H and K, however, and also show UV Ceti-type flares. Approximately 75% of the BY Dra variables are known as double-line spectroscopic binaries.

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