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11.
A. V. Krylov L. V. Mossakovskaya Kh. F. Khaliullin A. I. Khaliullina 《Astronomy Reports》2003,47(7):551-561
Using the four-channel automatic photoelectric photometer of the Sternberg Astronomical Institute’s Tien Shan Mountain Observatory, we have acquired accurate (σobs≈0.004m) W BV R brightness measurements for the eclipsing binary AR Cas during selected phases before eclipse ingress and after egress, as well as at the center of minima. A joint analysis of these measurements with other published data has enabled us to derive for the first time a self-consistent set of physical and geometrical parameters for the star and the evolutionary age of its components, t=(60±3)×106 years. We have found the period of the apsidal motion (Uobs=1100±160 years, \(\dot \omega _{obs} = 0^\circ .327 \pm 0^\circ .049\) years?1) and the apsidal parameter of the primary, logk 2,1 obs =?2.41±0.08, with the apsidal parameter being in good agreement with current models of stellar evolution. There is an ultraviolet excess in the primary’s radiation, Δ(U?B)=?0.12m and Δ(B?V)=?0.06m, possibly due to a metal deficiency in the star’s atmosphere. 相似文献
12.
Astronomy Reports - The variations in the orbital period of the eclipsing binary system V505 Sgr, which is a part of the visual binary system CHR 90, have been analyzed. It has been shown that the... 相似文献
13.
A. I. Khaliullina 《Astronomy Reports》2018,62(8):520-531
Cyclic variations of the orbital period superposed on a secular period decrease have been found for the Algol-type eclipsing binaries TU Her, TY Peg, and Y Psc. A superposition of two kinds of cyclic variations is observed for TU Her and Y Psc: with periods of 69.4 years and 30.0 years for TU Her, and 34.4 and 23.2 years for Y Psc. One type of oscillation, with a period of 74.3 years, was detected for TY Peg. The cyclic orbital-period variations of TY Peg and Y Psc can be successfully fitted using the light-time effect, and also with magnetic oscillations. In the case of TU Her, the light-time effect is able to explain only one of the cyclic variations, the one with the shorter period. 相似文献
14.
A. V. Krylov L. V. Mossakovskaya Kh. F. Khaliullin A. I. Khaliullina 《Astrophysics and Space Science》1989,154(2):343-355
List of forthcoming papers 相似文献
15.
A. I. Khaliullina 《Astronomy Reports》2014,58(8):545-553
A detailed study of orbital-period variations was performed for TY Del and RY Cnc, which are both Algol-type eclipsing binaries with late-type second aries; for RY Cnc, this is the first study of this kind. The period variations of both stars can be considered a superposition of a secular period increase and cyclic changes of this period. The secular period increase can be explained as the effect of a uniform transfer of mass from the lower-mass to the higher-mass component, with the total angular momentum conserved. The mass-transfer rate is about 1.25 × 10⊙ M ⊙/year for TY Del and (0.68?1.02) × 10?8 M ⊙/year for RY Cnc. The cyclic period variations of the eclipsing binaries TY Del and RY Cnc could be due to either the presence of a third body in the system or the influence of magnetic activity of the secondary. 相似文献
16.
M. V. Kuznetsov Kh. F. Khaliullin A. I. Khaliullina V. G. Metlov L. V. Mossakovskaya 《Astronomy Reports》2011,55(11):989-999
We have derived the first photoelectric light curve of the eclipsing binary V974 Cyg from our own photoelectric observations.
Analysis of the light curve has yielded the system’s photometric elements (r
1 ≈ r
2 = 0.1192, e = 0.058, L
1 ≈ L
2 = 0.486, and L
3 = 0.028) and absolute parameters (M
1 ≈ M
2 = 2.2M
⊙, T
eff,1 ≈ T
eff,2 = 9500 K, a = 15.0R
⊙, distance d = 1.29 kpc, age log t = 8.0, t/tMS = 0.11). We have detected apsidal motion with the period U
obs
= (1140 ± 170) yrs, and the presence of a third body in the system. The orbital parameters derived for the third body are
P
3 = 26.5 yrs, e
3 = 0.78, and a
3 sin i
3 = 1.5 AU; and the lower limit for its mass is M
3 > 0.58M
⊙. The observed apsidal-motion rate is higher than is expected theoretically by a factor of 1.5. The axial rotation of the
system’s components is not yet synchronized with the orbital motion, probably because V974 Cyg is relatively young and detached. 相似文献
17.
A. I. Khaliullina 《Astronomy Reports》2017,61(7):612-623
Orbital-period variations of the eclipsing binaries FK Aql and FZ Del are analyzed. For each of the systems, a superposition of two cyclic variations of their orbital periods is found. FK Aql may be a quadruple system that contains two more bodies, besides the eclipsing binary, with masses M 3 ? 1.75M ⊙ and M 4 ? 1.47M ⊙, and the corresponding periods 15 and 82 yrs. This could also be a triple system with a third body of mass M 3 ? 1.75M ⊙ and a period of the long-period orbit P 3 = 15 yrs, or with a third body of mass M 3 ? 1.30M ⊙ and a period of the long-period orbit P 3 = 82 yrs. FZ Del may be a quadruple system with the additional componentmasses M 3 ? 0.2M ⊙ and M 4 ? 0.3M ⊙, with the periods 10.2 and 53.7 yrs. This could also be a triple system with a third-body mass M 3 ? 0.2M ⊙ and a period of the long-period orbit P 3 = 10.2 yrs. In both systems, the residual period variations could be due to magnetic cycles of the secondary. The period variations of the eclipsing binary FZ Del could also be due to apsidal motion, together with the influence of a third body or the effects of magnetic activity. 相似文献
18.
A. I. Khaliullina 《Astronomy Reports》2017,61(10):859-870
Variations of the orbital periods of the eclipsing binaries TU Cnc, VZ Leo, and OS Ori are analyzed. Secular period decreases were earlier believed to occur in these systems. It is demonstrated that the period variations of TU Cnc can be represented using the light-time effect corresponding to the orbital motion of the eclipsing binary with a period of 78.6 years around the center ofmass of the triple system, with the mass of the third body being M 3 > 0.82M ⊙. With the same accuracy, the period variations of VZ Leo and OS Ori can be represented either solely using the light-time effect, or a superposition of a secular period decrease and the light-time effect. For VZ Leo, the period of the long-term orbit is 63.8 years in the former case and 67.9 years in the latter case. Similar masses for the third body are indicated in both cases: M 3 > 0.55M ⊙ and M 3 > 0.61M ⊙. For OS Ori, the period of the long-term orbit is 46 years and M 3 > 0.5M ⊙ in the former case, and the period is 36 years and M 3 > 0.6M ⊙ in the latter case. 相似文献
19.
Based on 70 years of published photoelectric observations, we have detected quasi-periodic cophased oscillations of the times of the primary and secondary minima of RR Lyn, one of the brightest and nearest eclipsing binaries in the northern sky ( $V = 5\mathop m\limits_. 54$ ; r=74 pc). Approximating these oscillations using the light equation yields estimates of the orbital parameters of the third body in the system and imposes constraints on its mass, M 3. In the most probable case when the orbits of the eclipsing and triple systems are coplanar, M 3=1.10±0.02M ⊙, and the semimajor axis of the orbit A 3=17.4±3.5 AU, with a substantial eccentricity, e 3=0.96±0.02. We have carried out a detailed study of the apsidal rotation of this eclipsing and now multiple system, which was suggested by Koch as a test of general relativity as far back as 1973. Our high-precision W BV R photoelectric photometry $(\sigma _{obs} \cong 0\mathop m\limits_. 0032)$ has removed some contradictions. At the same time, the proximity of the longitude of periastron ω 180°; the close correlation between the jointly estimated values of ω, e and the limb-darkening coefficients for the component disks, u 1 and u 2; and microfluctuations in the brightnesses of the stars prevent determination of the rate of rotation of the elliptical orbit in the system, even using the most accurate measurements. 相似文献
20.
Astronomy Reports - We have performed an analysis of the variations of the orbital period of the eclipsing binary system W Del. It is shown that its period changes with almost equal accuracy can be... 相似文献