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1.
In this study complete BV light curves of the W Ursae Majoris binary V1073 Cygni obtained in 2005 are presented. We have used the spectroscopic data of V1073 Cyg obtained by Ahn et al. (1992) for analysis. The analysis of radial velocity and light curves was made with Wilson} program (1998) and the geometric and physical elements} of the system were derived. By searching the simultaneous} solutions of the system, we have determined the masses and radii of the components: 1.64M⊙, 2.275R⊙ for the primary component and 0.55M⊙, 1.397R⊙ for the secondary component respectively. The effective temperature of 6494 ± 53 K for the secondary component was also estimated. 相似文献
2.
Observational evidence of unstable behavior for the W UMa-type binary system V1073 Cygni is presented in this paper.Having collected 111 times of minimum light during 1930–1998, we analyzed the change in the orbital period of this system. A perioddecrease was detected. Comparing the photoelectricobservations in 1963–64 with that made in 1988–91, obvious variable O'Connell effect of the light curves in V can be seen. Possible reasons for the unstable behavior of V1073 Cyg were discussed. 相似文献
3.
Complete UBV light curves of the W Ursae Majoris binary V839 Ophobtained in the year 2000 are presented. The available spectroscopic
data of V839 Oph is new and we used the first radial velocity data of this system obtained by Rucinski and Lu (1999)for analysis.
The radial velocity and light curves analysis was made with the latest version of Wilson programme (1998) and the geometric
and physical elements of the system are derived. By searching the simultaneous solutions of the system we have determined
the masses and radii of the components: 1.61M
⊙and 1.49402R
⊙ for the primary component; 0.50M
⊙and 0.90147R
⊙ for the secondary component. We estimate deffective temperatures of 6650±18 (K) for the primary and6554±15 (K) for the secondary
component.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
C. Sezer 《Astrophysics and Space Science》1993,208(1):15-31
Photoelectric observations of the eclipsing binary V 1073 Cyg have been carried out inB andV colours at the Ege University Observatory. The light curves were analyzed with the Wilson-Devinney approach. A period study reveals that the orbital period of the system is decreasing at the rate of (3.21 ± 0.17) second per century. 相似文献
5.
Photoelectric observations, in U, B and V, of the system GO Cygni were obtained during 1995 at the Birouni Observatory, Shiraz,
Iran, and the corresponding light curves analysed with the use of Wilson-Devinney;'s techniques. New photoelectric and absolute
elements for the system are given. The period of the system, a reverse Algol type semi-detached binary was found to continue
its increasing.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
New CCD observations of the eclipsing binary TZ Boo in BVR bands were carried out in 2006 (presented three new minima) and used together with all published minima to study and update the orbital period of the system TZ Boo by means of an (O–C) diagram. The period variation from 1926 to 2011 is represented by polynomial of eighth degree and indicates period variation of about 9.752 × 10???10 days/yr. We studied light curve stability over 85 yr covering all published observations in the V band and confirm the cyclic light curve variations. 相似文献
7.
Qing-Yao Liu Yu-Lan Yang National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming 《中国天文和天体物理学报》2006,6(3):331-337
The variation in the orbital period of the W UMa type contact binary V502 Oph is analyzed. The orbital period exhibits a wavelike variation with a periodicity of 23.0 years and an amplitude of △P = 1.24×10~(-6) days superimposed on secular decrease of dP/dt = 1.68×10-7 day per year. The long-term decrease may be accompanied by the contraction of the secondary at a rate of 83 m per year and a mass transfer rate from the primary to the secondary of 4.28×10~8 M per year. The short-term oscillation may be explained by the presence of a third component. Orbital elements of the third body and its possible mass are presented. 相似文献
8.
Hu-Shan Xu Li-Ying Zhu Sarotsakulchai Thawicharat Soonthornthum Boonrucksar 《天文和天体物理学研究(英文版)》2022,(3):252-262
The photometric solutions of the ultrashort period close binary V0644 Ser based on our new complete BVRI light curves are derived by the Wilson-Devininney code.... 相似文献
9.
M. C. Akan 《Astrophysics and Space Science》1987,135(1):157-167
The long-period eclipsing binary star V367 Cygni has been observed photoelectrically in two colours,B andV, in 1984, 1985, and 1986. These new light curves of the system have been discussed and compared for the light-variability with the earlier ones presented by Heiser (1962). Using some of the previously published photoelectric light curves and the present ones, several primary minima times have been derived to calculate the light elements. Any attempt to obtain a photometric solution of the binary is so complicated by the peculiar nature of the light curve caused by the presence of the circumstellar matter in the system. Despite this difficulty, however, some approaches are being carried out to solve the light curves which will be discussed shortly. 相似文献
10.
Ai-Ying Zhou Shi-Yang Jiang B. Chayan Bai-Tian Du 《Astrophysics and Space Science》2002,281(4):699-714
The new time-resolved CCD photometry of XX Cyg was presented. We investigate the time-dependent behaviour of the light variations
by reanalyzing the data in the literature. XX Cyg was demonstrated beyond any doubt again to be a monoperiodic pulsator. Its
light curves can be well reproduced by the sinusoids with the fundamental frequency f
0 = 7.41481 ± 0.00001 cycle d-1(P
0 = 0d
. 1348652 ± 0.0000001) and its first nine harmonics. Fourier, wavelet and O–C analyses based on all the available data reveals
the amplitude and period variations during the years 1974 to 2000.The general trend of the amplitude changes is decreasing
at a rate of one percent milli-magnitudes per year. The parabolic analysis on the updated 101 times of maximum light suggests
a slowly continuous increasing at a rate of 1.3 × 10-3 days per million years in the period.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
Five color UBVRI photometric and polarimetric measurements of the eclipsing binary VW Cyg are reported. It is shown that in the primary minimum the luminosity is attenuated (at short wavelengths) even after passage of the second contact. This fact is interpreted as evidence of gaseous structures in the system. The exchange of matter among the system components is also confirmed by the O-C curve constructed from data covering nearly a hundred years. Polarimetric analysis makes it possible to isolate the intrinsic (P=0.030±0.02) and interstellar components of the polarization. The UBVRI light curves of VW Cyg have been resolved. This was done using an algorithm for synthesizing theoretical light curves in the Roche model. Good agreement was obtained between the theoretical curves and observations in the V, R, and I bands, but the observed minimum depths in the U and B bands exceed the theoretical values. This appears to be caused by gas flows in the system. 相似文献
12.
H. Rovithis-Livaniou 《Astrophysics and Space Science》2005,296(1-4):91-99
A brief review of the physical mechanisms that could produce the observed orbital period changes in close binaries, the methods
used to study them, and a general discussion is given. 相似文献
13.
G. Djurašević O. Demircan S. Özdemir M. Tanriver Z. Müyesseroglu H. Ak B. Albayrak 《Astrophysics and Space Science》1997,253(2):265-274
The UBV observations of the massive binary BF Aur were made at the Ankara University Observatory during 1988, 1989 and 1996.
Asymmetry of the light curves, arising from unequal height of successive maxima, indicates that the system is active. By analysing
these observations in the framework of the Roche model (including the presence of bright regions on the components) one obtains
a semidetached configuration of the system, with the cooler secondary component filling its Roche lobe. The analysis of the
light curves yields consistent solutions for mass ratio q = m2/m1 somewhat less than one. The influence of the mass transfer on the change of the system-orbital-period is relatively small.
The upward parabolic character of the O–C diagram (Zhang et al., 1993) indicates a mass transfer from the less massive secondary
to the more massive primary. This inturn requires the less massive secondary to fill its Roche lobe. This is consistent with
our solution. Based on these facts we introduced the following working hypothesis. At the place where the gas stream from
the secondary falls on the primary, relatively small in size but a high temperature contrast active hot-spot (hs) region is
formed. As a result of the heating effect caused by the irradiation of the hot-spot region, on the secondary's side facing
the hot spot a bright-spot (bs) region is formed. The bright-spot region is larger in size but with significantly lower temperature
than the hot spot. This region can be treated as a ‘reflection cap’. By analysing the light curves in the framework of this
working hypothesis the basic parameters of the system and the active regions are estimated. The problem is solved in two stages:
by obtaining a synthetic light curve in the case when the parameters of the corresponding Close Binary (CB) Roche model (Djurašević,
1992a) are given a priori (the direct problem) and by determining the parameters of the given model for which the best fit
between the synthetic light curve and the observations is achieved (the inverse problem) (Djurašević, 1992b).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
Atila Poro Mehmet Tanriver Elham Sarvari Shayan Zavvarei Hossein Azarara Laurent Corp Sabrina Baudart Asma Ababafi Nazanin Kahali Poor Fariba Zare Ahmet Bulut Ahmet Keskin 《天文和天体物理学研究(英文版)》2024,(4):194-215
The light curve analyses and orbital period variations for two contact binary stars,LS Del and V997 Cyg,are presented in this work which was conducted in the frame of the Binary Systems of South and North project Ground-based photometric observations were performed at two observatories in France.We used the Transiting Exoplanet Survey Satellite (TESS) data for extracting times of minima and light curve analysis of the targe systems. The O-C diagram for both systems displays a parabolic trend.LS ... 相似文献
15.
Qian Shengbang 《天文研究与技术》1999,(Z1)
1 IntroductionCKBoowasdiscoveredandconfirmedtobeacontactbinarybyBond ( 1 975 ) .Afteritsdis coverythesystemisobservedfrequently (e .g .Aslan ,1 978;AslanandDerman ,1 986 :PajdoszandZola ,1 987;Krzesinskietal.,1 991andJiaetal.,1 992 ) .Asreportedbyseveralauthors,thelightcurveofthesy… 相似文献
16.
We presented a low-precision spectrum for HI Leo,Transiting Exoplanet Survey Satellite data for V523 Cas,and new photometry for both K-type contact binaries.Comparing their light curves on different observing dates,we found small intrinsic variabilities,such as variable amplitudes for HI Leo and the varying heights around the second maxima for V523 Cas.By the Wilson-Devinney Code,we deduced six photometric solutions.The dark spot of V523 Cas may appear on the surface of the more massive componen... 相似文献
17.
The O–C curve of the contact binary CK Boo have been analyzed with Kalimeris et al. (1994) method. It is shown that the orbital period is changing in a quasi-sinusoidal form with a period of about ∼ 14 yr
superposed on a secular period increase. The correlation of the variations of the light level at MinI, MaxI and II in the
light curve implies that the luminosity of secondary component is variable. Comparing the change of the quasi-periodic component
in the orbital period with that of the secondary's luminosity, we find that the luminosity of the secondary component and
the orbital period may vary with the same cycle length ∼14 yr; the variation of the secondary's luminosity is in the same
phase with that of the orbital period. This connection is different from those of the RS CVn-type close binaries (e.g. CG
Cyg, V471 Tau, RT Lac). The mechanisms that may have produced this relation of the variations of the orbital period and the
luminosity of the secondary are also discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
Time-series CCD photometry of the contact system V839 Oph on May, June and July 2004 showed a continuous brightening of the system in all phases of the light curve. A possible explanation of this brightening could be enhanced (magnetic) activity of the system, also noticed in the past. Mass transfer and/or energy exchange between the two components can explain the observed increase of brightness. All possible cases, concerning the location and shape of the spotted area, are discussed and the most probable model is presented. 相似文献
19.
New UBV photometry of Algol-Type eclipsing binary star AI Dra andthe absolute physical parameters of this system have been presented.The light curve analysis carried out by the method of differentialcorrections indicates that both components are inside their Roche-Lobes.From combining the photometric solution with spectroscopic data obtainedfrom velocity curve analysis, it has been found that the system consistof a main sequence primary and an evolved (subgiant) secondary. 相似文献
20.
An algorithm for the solution of Fredholm's equations of the first kind describing light curves of WR + O binary systems on a set of nonnegative monotonically decreasing convex functions is developed. The algorithm is applied to the narrow-band continuum The λ4244 Ålight curve of the eclipsing binary V444 Cygni (WN5 + O6). Reliable information about the distribution of the linear absorption coefficientα (r) and the velocity law in the extended photosphere of the WN5 star is obtained from the analysis. Recent accurate spectrophotometric estimate of the luminosity ratio of the components in the binary was used to establish the relationship between the two geometrical parameters of the model: the radius of the O6 star and the orbital inclination. It is shown that the flow of matter in the WN5 photosphere is accelerating and that the value of the acceleration is relatively low. The expansion velocity at the distance r ? 3.8R ⊙ (at whichτ4244(r) ? 1) reaches a few hundreds km/s, i.e., the flow at this point is supersonic. 相似文献