scholarly journals The Spotted Contact Binary SS Arietis — Spectroscopy and Infrared Photometry

1992 ◽  
Vol 151 ◽  
pp. 379-382
Author(s):  
P.P. Rainger ◽  
S.A. Bell ◽  
R.W. Hilditch
Keyword(s):  
Imaging Techniques ◽  
Type System ◽  
Light Curves ◽  
Doppler Imaging ◽  
Mass Ratio ◽  
Infrared Photometry ◽  
High Quality ◽  
Precise Location ◽  
Medium Resolution ◽  
Contact Binary

The first infrared photometry for the W-UMa system SS Ari is presented. An analysis based on medium resolution spectroscopy presented here shows that SS Ari is a W-type system with a mass ratio of 0.33. It seems certain that the asymmetry in the published light curves and those obtained for this study can be explained by the effect of spots on one or possibly both components of the system. The precise location, size and temperature of these spots require the use of Doppler Imaging techniques in conjunction with high quality multi-band photometry.

scholarly journals UBVRI Photometric Analysis of the Solar-Type Eclipsing Binary TYC 3034-299-1

2012 ◽  
Vol 2012 ◽  
pp. 1-11
Author(s):  
Ronald G. Samec ◽  
Adam Jaso ◽  
Jesse White ◽  
Danny R. Faulkner ◽  
Nicholas Blum ◽  
...  
Keyword(s):  
Light Curve ◽  
Massive Star ◽  
Light Curves ◽  
Dark Spot ◽  
Mass Ratio ◽  
Photometric Analysis ◽  
Contact Binary ◽  
Solar Type ◽  
Curve Solution ◽  
Light Curve Solution

TYC 3034-0299-1 (CVn) is a magnetically active, contact binary, ROTSE variable. UBVRcIc light curves are presented along with a period study and a simultaneous UBVRI light curve solution. Our light curves show eclipse amplitudes of 0.72 and 0.62 mags (V) in the primary and secondary eclipses. Modeled results include a dark spot region, found at longitude 51°, a 24% Roche lobe fill-out, and a mass ratio of 0.48. A total eclipse is found to occur in the secondary eclipse making TYC 3034-0299-1 a W-type (less massive star is hotter) W UMa variable.

scholarly journals Searching for eclipsing binaries in the area of RA: 02h21m36s, Dec: +57○11′32″

2020 ◽  
Vol 497 (3) ◽  
pp. 3381-3392
Author(s):  
Di-Fu Guo ◽  
Kai Li ◽  
Xing Gao ◽  
Dong-Yang Gao ◽  
Zhi-Jian Xu ◽  
...  
Keyword(s):  
Binary Systems ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Mass Ratio ◽  
Contact Binaries ◽  
Contact Binary ◽  
Low Mass ◽  
Low Mass Ratio ◽  
Period Decrease ◽  
Cross Matching

ABSTRACT By analysing the data observed by the Comet Search Programme telescope at Xingming Observatory from 2018 October 11 to 2018 December 19, 24 eclipsing binaries were identified. By cross-matching with the VSX (AAVSO) website, we found that four binaries are newly discovered. By analysing the Transiting Exoplanet Survey Satellite (TESS) data, the light curves of 17 binaries were obtained. First photometric solutions of 23 binaries were obtained by simultaneously analysing all the light curves, except for NSVS 1908107 (first analysed by Pan et al.). Based on the photometric solutions, nine binaries belong to detached binary systems, ten binaries belong to semidetached binary systems, and five binaries belong to contact binary systems. Two W-subtype low-mass ratio contact binaries (the less massive components are hotter), with total eclipsing light curves, were identified: Mis V1395 is a deep contact binary (q = 0.150, $f=80{{\ \rm per\ cent}}$), while NSVS 1917038 is a low-mass ratio binary with an unexpectedly marginal contact degree (q = 1/6.839 = 0.146, $f=4{{\ \rm per\ cent}}$). The total eclipsing detached binary GSC 03698-00022 has an extremely low mass ratio of q = 0.085. The Algol-type binary NSVS 1908107 is also found to have an extremely low mass ratio of q = 0.081. The Algol-type binary DK Per exhibits a continuous period decrease at a rate of dP/dt = −1.26 × 10−7 d yr−1, which may result from the orbital angular momentum loss. Based on the light curves obtained from the TESS data, a pulsating binary candidate (NSVS 1913053) was found.

CSS J075415.6+191052 and NW Leo: two contact binaries at different evolutionary stages

2021 ◽  
Author(s):  
Xu-Dong Zhang ◽  
Shengbang Qian ◽  
Ergang Zhao ◽  
Qijun Zhi ◽  
Aijun Dong ◽  
...  
Keyword(s):  
Relaxation Oscillation ◽  
Thermal Relaxation ◽  
Light Curves ◽  
Secondary Component ◽  
High Mass ◽  
Dark Spot ◽  
Left Shoulder ◽  
Mass Ratio ◽  
Convective Envelope ◽  
Contact Binary

Abstract Multi-color light curves of CSS J075415.6+191052 and NW Leo are presented and the photometric solutions suggest that CSS J075415.6+191052 is a low mass ratio (q=0.178) and slightly deep contact binary (f=34.9%), while NW Leo with high mass ratio (q=0.707) and shallow degree of contact (f=2.3%). For CSS J075415.6+191052, the RI light curves show weakening around the left shoulder of secondary minimum, which indicates that there may be a dark spot on the secondary component. However, the light curves of BV bands are totally symmetric. It is unreasonable if the dark spot is caused by magnetic activity or mass transfers between two components. Therefore, the weakening of the light curves in this contact binary is caused by something else. A possible explanation is mass transferring from primary component to common convective envelope through the inner Lagrangian point, and this part of the mass, for some reason, weakens RI bands of light from secondary component. O - C analysis of NW Leo reveals a cyclic period change with a modulation period of 4.7 years, which may be caused by the light travel time effect of a third body. The positions of CSS J075415.6+191052 and NW Leo in P - J_{orb}' diagram suggest that the former is more evolved, which is in agreement with their photometric solutions. In the current stage, CSS J075415.6+191052 is dominated by the angular momentum loss theory, but NW Leo mainly follow the thermal relaxation oscillation theory.

scholarly journals The New Ephemeris and Light Curve Analysis of V870 Ara by the Ground-Based and TESS Data

2021 ◽  
Vol 30 (1) ◽  
pp. 37-44
Author(s):  
Atila Poro ◽  
Mark G. Blackford ◽  
Fatemeh Davoudi ◽  
Amirreza Mohandes ◽  
Mohammad Madani ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Curve Analysis ◽  
Light Curves ◽  
Mass Ratio ◽  
Light Curve Analysis ◽  
Photometric Observations ◽  
Photometric Elements ◽  
Contact Binary ◽  
Absolute Parameters

Abstract New CCD photometric observations and their investigation of the W UMa-type binary, V870 Ara, are presented. Light curves of the system were taken through BVIfilters from the Congarinni Observatory in Australia. The new ephemeris is calculated based on seven new determined minimum times, together with the TESS data and others compiled from the literature. Photometric solutions determined by the Wilson-Devinney (W-D) code are combined with the Monte Carlo simulation to determine the adjustable parameters’ uncertainties. These solutions suggest that V870 Ara is a contact binary system with a mass ratio of 0.082, a fillout factor of 96±4 percent, and an inclination of 73.60±0.64 degrees. The absolute parameters of V870 Ara were determined by combining the Gaia EDR3 parallax and photometric elements.

scholarly journals V752 Cen - A triple-lined spectroscopic contact binary with sudden and continuous period changes

2019 ◽  
Author(s):  
X Zhou ◽  
B Soonthornthum ◽  
S-B Qian ◽  
E Fernández Lajús
Keyword(s):  
Mass Transfer ◽  
Light Curves ◽  
Period Variation ◽  
Mass Ratio ◽  
Eclipsing Binary ◽  
Two Component ◽  
Massive Component ◽  
Contact Binary ◽  
The Absolute ◽  
Year 2000

Abstract V752 Cen is a triple-lined spectroscopic contact binary. Its multi-colour light curves were obtained in the years 1971 and 2018, independently. Photometric analyses reveal that the two sets of light curves produce almost consistent results. It contains a W-subtype totally eclipsing binary, and its mass ratio and fill-out factor are q = 3.35(1) and $f = 29(2)\, {{\ \rm per\ cent}}$. The absolute elements of its two component stars were determined to be M1 = 0.39(2)M⊙, M2 = 1.31(7)M⊙, R1 = 0.77(1)R⊙, R2 = 1.30(2)R⊙, L1 = 0.75(3)L⊙ and L2 = 2.00(7)L⊙. The period of V752 Cen is 0.37023198 day. The 0.37-d period remained constant from its first measurement in 1971 until the year 2000. However, it changed suddenly around the year 2000 and has been increasing continuously at a rate of dP/dt = +5.05 × 10−7day · year−1 since then, which can be explained by mass transfer from the less massive component star to the more massive one with a rate of $\frac{dM_{2}}{dt}=2.52\times {10^{-7}}M_\odot /year$. The period variation of V752 Cen over the 48 years in which the period has been monitored is really unusual, and is potentially related to effects from the possible presence of a nearby third star or of a pair of stars in a second binary.

scholarly journals Comprehensive photometric investigation of an active early K-type contact system—IL Cancri

2020 ◽  
Vol 72 (5) ◽  
Author(s):  
Nian-Ping Liu ◽  
Thawicharat Sarotsakulchai ◽  
Somsawat Rattanasoon ◽  
Bin Zhang
Keyword(s):  
Primary Component ◽  
Light Curves ◽  
Mass Ratio ◽  
Highly Active ◽  
Type Contact ◽  
Contact Binaries ◽  
Contact Binary ◽  
Photometric Investigation ◽  
The Masses ◽  
Good Agreement

Abstract Comprehensive photometric investigation of the early K-type contact binary IL Cnc was carried out. A few light curves from both ground-based telescopes and the Kepler space telescope were obtained (or downloaded) and then analyzed in detail. They are mostly found to be asymmetric and there are even continuously changing O’Connell effects in the light curves from Kepler K2 data, suggesting the system to be highly active. Using the Wilson–Devinney code (version 2013), photometric solutions were derived and then compared. It is found that the calculation of the mass ratio is easily affected by the spot settings. Combining the radial velocities determined from LAMOST median resolution spectral data, the mass ratio of the binary components is found to be M2/M1 = 1.76 ± 0.05. The components are in shallow contact ($f\sim 9\%$) and have a temperature difference about T2 − T1 = −280 ± 20 K. The system is demonstrated to be W-subtype, which may be a common feature of K-type contact binaries. The masses of the binary components were estimated to be $M_1\sim 0.51\, M_{\odot }$ and $M_2\sim 0.90\, M_{\odot }$. The values are in good agreement with that deduced from the parallax data of Gaia. The results suggest that the primary component lacks luminosity compared with the zero main sequence. The Hα spectral line of the primary component is found to be peculiar. Combining newly determined minimum light times with those collected from literature, the orbital period of IL Cnc is studied. It is found that the (O − C) values of the primary minima show sinusoidal variation while those of the secondary do not. The oscillation is more likely to be caused by the starspot activities, yet this assumption needs more data to support.

scholarly journals New Photometric Investigation of the Solar-Type Shallow-Contact Binary HH Bootis

2019 ◽  
Vol 2019 ◽  
pp. 1-18
Author(s):  
Jia-jia He ◽  
Jing-jing Wang
Keyword(s):  
Light Curves ◽  
Mass Ratio ◽  
Third Body ◽  
Light Minimum ◽  
Short Period ◽  
Cyclic Oscillation ◽  
Type Contact ◽  
Contact Binary ◽  
Solar Type ◽  
Photometric Investigation

The short-period solar-type contact binary HH Boo was monitored photometrically for about 8 years. It is found that the CCD light curves in the B, V, R, and I bands obtained in 2010 are symmetric, while the multicolor light curves observed in 2011 and 2012 by several investigators showed a positive O’Connell effect where the maxima following the primary minima are higher than the other ones. This indicates that the light curve of the solar-type contact binary is variable. By analyzing our multicolor light curves with the Wilson-Devinney code (W-D code), it is confirmed that HH Boo is a W-type shallow-contact binary system with a mass ratio of q = 1.703(31) and a degree of contact factor of f = 12.86%(0.73%). By including 109 new determined times of light minimum together with those compiled from the literature, it is detected that the O-C diagram shows a cyclic oscillation with a period of T3 = 6.58(11) yr and an amplitude of A3 = 0.0018(1) d. The cyclic change may reveal the presence of an extremely cool third body orbiting the central binary.

scholarly journals Surface Brightness Variation of the Contact Binary SW Lac: Clues From Doppler Imaging

2011 ◽  
Vol 7 (S282) ◽  
pp. 496-497
Author(s):  
Hakan Volkan Şenavcı
Keyword(s):  
Light Curve ◽  
Surface Brightness ◽  
Brightness Variation ◽  
Curve Analysis ◽  
Light Curves ◽  
Doppler Imaging ◽  
Light Curve Analysis ◽  
Modeling Process ◽  
Circular Spot ◽  
Contact Binary

AbstractIn this study, we present the preliminary light curve analysis of the contact binary SW Lac, using B, V light curves of the system spanning 2 years (2009 - 2010). During the spot modeling process, we used the information coming from the Doppler maps of the system, which was performed using the high resolution and phase dependent spectra obtained at the 2.1m Otto Struve Telescope of the McDonald Observatory, in 2009. The results showed that the spot modeling from the light curve analysis are in accordance with the Doppler maps, while the non-circular spot modeling technique is needed in order to obtain much better and reliable spot models.

scholarly journals On the Short Time Scale Evolutionary History of the Contact Binary VW Cephei

1998 ◽  
Vol 11 (1) ◽  
pp. 396-396
Author(s):  
I. Pustylnik
Keyword(s):  
Evolutionary History ◽  
Light Curves ◽  
Published Data ◽  
Short Time Scale ◽  
Flare Activity ◽  
Considerable Portion ◽  
History Of ◽  
Contact Binary ◽  
Elongation Phase ◽  
Short Time

We study the short-time evolutionary history of the well-known contact binary VW Cep. Our analysis is based partly on the numerous UBV lightcurves obtained at Tartu Observatory, IUE spectra, and samples from the published data. Special attention is given to the effects of asymmetry of the light curves. A higher degree of asymmetry outside the eclipses along with the significant displacements of the brightness maxima in respect to the elongation phase is interpreted as evidence that a considerable portion of the flaring source is concentrated close to the neck connecting the components. We discuss the nature of asymmetry in terms of possible mass exchange and the flare activity and compare the results of our model computations with the record of orbital period variations over the last 60 years.

scholarly journals Optimization of X-ray Investigations in Dentistry Using Optical Coherence Tomography

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4554
Author(s):  
Ralph-Alexandru Erdelyi ◽  
Virgil-Florin Duma ◽  
Cosmin Sinescu ◽  
George Mihai Dobre ◽  
Adrian Bradu ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Radiation Dose ◽  
Imaging Techniques ◽  
Image Resolution ◽  
Optical Coherence ◽  
X Rays ◽  
High Quality ◽  
X Ray

The most common imaging technique for dental diagnoses and treatment monitoring is X-ray imaging, which evolved from the first intraoral radiographs to high-quality three-dimensional (3D) Cone Beam Computed Tomography (CBCT). Other imaging techniques have shown potential, such as Optical Coherence Tomography (OCT). We have recently reported on the boundaries of these two types of techniques, regarding. the dental fields where each one is more appropriate or where they should be both used. The aim of the present study is to explore the unique capabilities of the OCT technique to optimize X-ray units imaging (i.e., in terms of image resolution, radiation dose, or contrast). Two types of commercially available and widely used X-ray units are considered. To adjust their parameters, a protocol is developed to employ OCT images of dental conditions that are documented on high (i.e., less than 10 μm) resolution OCT images (both B-scans/cross sections and 3D reconstructions) but are hardly identified on the 200 to 75 μm resolution panoramic or CBCT radiographs. The optimized calibration of the X-ray unit includes choosing appropriate values for the anode voltage and current intensity of the X-ray tube, as well as the patient’s positioning, in order to reach the highest possible X-rays resolution at a radiation dose that is safe for the patient. The optimization protocol is developed in vitro on OCT images of extracted teeth and is further applied in vivo for each type of dental investigation. Optimized radiographic results are compared with un-optimized previously performed radiographs. Also, we show that OCT can permit a rigorous comparison between two (types of) X-ray units. In conclusion, high-quality dental images are possible using low radiation doses if an optimized protocol, developed using OCT, is applied for each type of dental investigation. Also, there are situations when the X-ray technology has drawbacks for dental diagnosis or treatment assessment. In such situations, OCT proves capable to provide qualitative images.

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