scholarly journals ST Carinae, An Algol-Type System in a Possible State of Rapid Mass Exchange

1989 ◽  
Vol 107 ◽  
pp. 335-335
Author(s):  
C.R. Chambliss ◽  
R.L. Walker
Keyword(s):  
Mass Exchange ◽  
Type System ◽  
Primary Component ◽  
Roche Lobe ◽  
Mass Ratio ◽  
Eclipsing Binary ◽  
Additional Work ◽  
Wood Model ◽  
Rapid Mass ◽  
Substantial Uncertainty

ST Carinae is an eclipsing binary with a period of 0.90165 days and is believed to consist of an A0 V primary and a secondary of type F5 - 8 IV. About 900 observations in UBV, made by Somerville in 1963, but unreduced at that time, are analyzed with the Wood Model. These are also compared with the solutions obtained by previous investigators of this system. The solutions indicate a reasonably consistent geometry, but there is still substantial uncertainty with regard to the mass-ratio and dynamical status of the system. The possibility exists that ST CAR is in the initial and rapid stage of mass exchange in which the primary component fills its Roche lobe and is losing mass to its companion. The two components of ST CAR appear to be of normal dimensions, but additional work is needed to clarify the exact status of this system. It is planned that a re-analysis using the Simplex program will clarify the dynamical status of ST CAR.

scholarly journals δ Sct-Type Pulsators in Eclipsing Binary Systems: the Case of RZ Cas

2002 ◽  
Vol 185 ◽  
pp. 102-103
Author(s):  
E. Rodríguez ◽  
V. Costa ◽  
M.J. López-González ◽  
J.M. García ◽  
S.L. Kim ◽  
...  
Keyword(s):  
Binary System ◽  
Binary Systems ◽  
Hot Spot ◽  
Primary Component ◽  
Roche Lobe ◽  
Light Curves ◽  
Eclipsing Binary ◽  
Preliminary Results ◽  
The Impact

AbstractRZ Cas is an Algol-type eclipsing binary system where the primary component was recently discovered as a δ Set pulsator. A three-continent multisite photometric campaign was carried out during 1999. Preliminary results are reported here indicating a semi-detached system where the secondary fills its Roche lobe. The light curves also suggest a hot spot on the surface of the primary component as a consequence of the impact of the mass stream from the secondary. The pulsational behaviour can be well described with only one frequency.

scholarly journals The Evolution of Close Binaries and the Formation of the Wolf-Rayet Stars

1968 ◽  
Vol 1 ◽  
pp. 409-413 ◽  
Author(s):  
Bohdan Paczyński
Keyword(s):  
Mass Exchange ◽  
Massive Star ◽  
Small Mass ◽  
Roche Lobe ◽  
Close Binaries ◽  
Mass Star ◽  
The Core ◽  
Massive Component ◽  
Rapid Mass

I shall discuss here the evolution of massive binaries in the case B. In this case the initially more massive component fills up the Roche lobe after the exhaustion of hydrogen in the core. By a massive binary I understand the binary in which the phase of a rapid mass exchange is terminated by helium ignition in the core of the initially more massive star. The helium ignition stops the contraction of the core and the expansion of the envelope of that component. In a small mass star the degeneracy plays the role of helium ignition in this respect. The last case will be discussed by Dr. A. Weigert in his lecture.

scholarly journals AY Vulpeculae

1989 ◽  
Vol 107 ◽  
pp. 374-374
Author(s):  
R.L. Walker
Keyword(s):  
Type System ◽  
Roche Lobe ◽  
Eclipsing Binaries ◽  
Secondary Component ◽  
Photometric Study ◽  
Orbital Elements ◽  
Primary Minimum ◽  
Astrophysical Interest ◽  
Naval Observatory ◽  
Wood Model

The star AY Vulpeculae was recognized as variable and labeled as an Algol-type system by Hoffmeister, (A.N. 242, 133, 1931). Koch et al. (I.B.V.S. 1709 1979), included it in their list of eclipsing binaries for which photoelectric work was needed. The system is faint, but because its primary minimum is very deep it is of astrophysical interest. The observations of the present investigation represent the first definitive photometric study made of AY VUL and is one of several systems with periods greater than two days being observed with the 1.0 meter Ritchey-Chretian reflector at the Flagstaff Station . A total of 1242 observations of AY Vul (406 in V, 417 in B, and 419 in U) were obtained on 12 nights in 1986.Orbital elements for AY VUL were obtained by using the Wood model, and the calculations were performed on the VAX 11/750 computer at the Flagstaff Station of the U. S. Naval Observatory. AY Vulpeculae can be regarded as a classical Algoltype semidetached system in which the secondary component fills its Roche lobe, while the primary lies well inside its own lobe. Both eclipses are partial. The orbital elements are listed below.

St Carinae, an Algol-type system in a possible state of rapid mass exchange

1989 ◽  
Vol 50 (1-2) ◽  
pp. 335-335
Author(s):  
C.R. Chambliss ◽  
R.L. Walker
Keyword(s):  
Mass Exchange ◽  
Type System ◽  
Rapid Mass

scholarly journals Results of a Cooperative Investigation of RY Scuti

1989 ◽  
Vol 107 ◽  
pp. 350-350
Author(s):  
M.I. Kumsiashvili
Keyword(s):  
Mass Exchange ◽  
Spectroscopic Data ◽  
Model Atmosphere ◽  
Primary Component ◽  
Mass Ratio ◽  
Helium Content ◽  
Preliminary Results ◽  
Helium Star

Some preliminary results are given of a cooperative investigation of the highly interesting radio object RY Set. From spectroscopic data the mass-ratio was found to be q=m2/m1 ≈ 3.3. An attempt to determine the helium content by model-atmosphere techniques has shown that the atmosphere of the primary component has a large helium excess; the star has every characteristic of a helium star formed by mass exchange in case B. The analysis suggests that RY Set may offer a rare chance to observe a massive system at the stage when "switching of the roles" is complete and a helium remnant with a hydrogen shell is beginning to develop the characteristics of a WR-star.

scholarly journals KIC 8553788: A pulsating Algol with an extreme mass ratio

2018 ◽  
Vol 616 ◽  
pp. A130 ◽  
Author(s):  
A. Liakos
Keyword(s):  
Radial Velocity ◽  
Spectral Type ◽  
Primary Component ◽  
Photometric Data ◽  
Light Curves ◽  
Secondary Component ◽  
Mass Ratio ◽  
Eclipsing Binary ◽  
Detached Binaries ◽  
Absolute Parameters

Context. The present research paper focuses on the eclipsing binary KIC 8553788 which belongs to two different types of binary systems regarding its physical properties. In particular, it is one of the 71 oscillating stars of Algol-type that have been discovered so far and one of the six that have been published based on high-cadence photometric data of the Kepler mission. In addition, it is one of the four semi-detached binaries of the group of R CMa-type systems, while its pulsating component has the fourth fastest frequency among the δ Scuti stars-members of semi-detached binaries. Detailed light curves as well as spectroscopic and pulsation analyses are presented, while possible explanation scenarios for the evolution of the system involving past mass transfer, mass loss, and/or angular momentum loss due to the presence of a tertiary component are discussed. Aims. The goal of the study is to extract the pulsational characteristics of the oscillating star of the system, to estimate the absolute parameters of its components, and to provide a possible explanation for its extreme evolutionary status. Methods. Ground-based spectroscopic observations using the 2.3 m “Aristarchos” telescope were obtained and used for the estimation of the spectral type of the primary component and to model the light curves of the system with higher certainty. The short-cadence photometric data provided by the Kepler mission were analysed using standard eclipsing binary modelling techniques, while Fourier analysis was applied on their residuals aiming to reveal the properties of the intrinsic oscillations. The resulting photometric model was combined with a published radial velocity curve to obtain accurate absolute parameters for the components of the system. Results. The results show that the primary component of the system is of A8 spectral type, has a mass of 1.6 M⊙, and a radius of 2 R⊙. It is a relatively fast pulsator of δ Scuti type that oscillates in 89 frequency modes with the dominant one being 58.26 cycles day−1. On the other hand, the secondary component has a mass of only 0.07 M⊙, a radius of 1 R⊙, and a temperature of 4400 K. In addition, it was found to be magnetically active with migrating cool spots on its surface. Conclusions. KIC 8553788, according to its geometrical configuration and its pulsational properties, belongs to the group of oscillating stars of Algol type, while according to its very low mass ratio and its relatively short orbital period belongs also to the group of R CMa stars. If confirmed by radial velocity data of the secondary component, the system would have the lowest mass ratio that has ever been found in semi-detached systems and could therefore be considered as one of the most extreme cases.

The Eclipsing Binary WX Eridani

1979 ◽  
Vol 46 ◽  
pp. 385
Author(s):  
M.B.K. Sarma ◽  
K.D. Abhankar
Keyword(s):  
Light Curve ◽  
Spectral Type ◽  
Orbital Period ◽  
Primary Component ◽  
Light Curves ◽  
Absorption Feature ◽  
Primary Star ◽  
Eclipsing Binary ◽  
The Times ◽  
Phase Angles

AbstractThe Algol-type eclipsing binary WX Eridani was observed on 21 nights on the 48-inch telescope of the Japal-Rangapur Observatory during 1973-75 in B and V colours. An improved period of P = 0.82327038 days was obtained from the analysis of the times of five primary minima. An absorption feature between phase angles 50-80, 100-130, 230-260 and 280-310 was present in the light curves. The analysis of the light curves indicated the eclipses to be grazing with primary to be transit and secondary, an occultation. Elements derived from the solution of the light curve using Russel-Merrill method are given. From comparison of the fractional radii with Roche lobes, it is concluded that none of the components have filled their respective lobes but the primary star seems to be evolving. The spectral type of the primary component was estimated to be F3 and is found to be pulsating with two periods equal to one-fifth and one-sixth of the orbital period.

scholarly journals New Data on the Eclipsing Binary V1848 Ori and Improved Orbital and Light Curve Solutions

2020 ◽  
Vol 29 (1) ◽  
pp. 72-80 ◽  
Author(s):  
Fatemeh Davoudi ◽  
Atila Poro ◽  
Fahri Alicavus ◽  
Afshin Halavati ◽  
Saeed Doostmohammadi ◽  
...  
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Mass Function ◽  
Light Curves ◽  
Complete Analysis ◽  
Physical Parameters ◽  
Mass Ratio ◽  
Third Body ◽  
Eclipsing Binary

AbstractNew observations of the eclipsing binary system V1848 Ori were carried out using the V filter resulting in a determination of new times of minima and new ephemeris were obtained. We presented the first complete analysis of the system’s orbital period behavior and analysis of O-C diagram done by the GA and MCMC approaches in OCFit code. The O-C diagram demonstrates a sinusoidal trend in the data; this trend suggests a cyclic change caused by the LITE effect with a period of 10.57 years and an amplitude of 7.182 minutes. It appears that there is a third body with mass function of f (m3) = 0.0058 M⊙ in this binary system. The light curves were analyzed using the Wilson-Devinney code to determine some geometrical and physical parameters of the system. These results show that V1848 Ori is a contact W UMa binary system with the mass ratio of q = 0.76 and a weak fillout factor of 5.8%. The O’Connell effect was not seen in the light curve and there is no need to add spot.

scholarly journals KIC 2557430: A Triple System Containing One γ Dor and Two Flaring Components?

2017 ◽  
Vol 34 ◽  
Author(s):  
Ceren Kamil ◽  
Hasan Ali Dal
Keyword(s):  
Triple System ◽  
Primary Component ◽  
Mass Ratio ◽  
Third Body ◽  
Period Analysis ◽  
Active Star ◽  
Group 2 ◽  
Different Sources ◽  
Flare Frequency ◽  
Group 1

AbstractThe results are presented for eclipsing binary KIC 2557430. The mass ratio was computed as 0.868 ± 0.002, while the inclination (i) was found as 69°.75 ± 0°.01 with T2 = 6271±1 K. 50 frequencies were found in the period analysis. 48 frequencies of them are caused due to the primary component, a γ Doradus star, while two of them are caused by the cool spots. 69 flares were detected in the analyses. Two OPEA models were derived for flares, which indicates that the flares were come from two different sources. The Plateau value was found to be 1.4336 ± 0.1104 s for Source 1, which is seen as possible the secondary component and 0.7550 ± 0.0677 s for Source 2, which is seen as possible third body. The half-life value was computed as 2278.1 s for Group 1 and 1811.2 s for Group 2. The flare frequency N1 was found to be 0.02726 h−1 and N2 was computed as 0.00002 for Group 1, while N1 was found to be 0.01977 h−1 and N2 was computed as 0.00001 for Group 2. In a results, KIC 2557430 is a possible triple system consisting of a γ Doradus-type star, a chromospherically active star, and also a flaring third body.

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