Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userPhotometric and Spectroscopic Observations of the Algol Type Binary V Triangle
130
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Time-series, multi-color photometry and high-resolution spectra of the short period eclipsing binary V Tri were obtained by observations. The completely covered light and radial velocity curves of the binary system are presented. All times of light minima derived from both photoelectric and CCD photometry were used to calculate the orbital period and new ephemerides of the eclipsing system. The analysis of $O-C$ diagram reveals that the orbital period is $0.58520481 days$, decreasing at a rate of $dP/dt=-7.80times10^{-8} d yr^{-1} $. The mass transfer between the two components and the light time-travel effect due to a third body could be used to explain the period decrease. However, a semidetached configuration with the less-mass component filling and the primary nearly filling each of their Roche lobes was derived from the synthesis of the light and radial velocity curves by using the 2015 version of the Wilson-Devinney code. We consider the period decrease to be the nonconservative mass transfer from the secondary component to the primary and the mass loss of the system, which was thought to be an EB type while it should be an EA type (semi-detached Algol-type) from our study. The masses, radii and luminosities of the primary and secondary are $1.60pm0.07 M_odot$, $1.64pm0.02 R_odot$, $14.14pm0.73 L_odot$ and $0.74pm0.02 M_odot$, $1.23pm0.02 R_odot$, $1.65pm0.05 L_odot$, respectively.
rate research
Read More
We present the multi-color, five-year light curves and the first radial velocities of the near-contact binary system KR Cyg. We derived the masses of the components as 2.88$pm$0.20 M$_{odot}$ and 1.26$pm$0.07 M$_{odot}$ and the radii as 2.59$pm$0.06 R$_{odot}$ and 1.80$pm$0.04 R$_{odot}$. Analyses of the UBVR light curves and the radial velocities indicate that none of the components exactly fill their corresponding Roche lobes. We have calculated the distance to the system of KR Cyg as {411$pm$12} pc using the observed apparent UBV magnitudes and the bolometric corrections for the component stars. We also searched for the empirical determination of albedo and effective temperature of the cooler, less massive star of KR Cyg, and of two similar near contact binaries AK CMi, and DO Cas. The residuals between the observed and computed fluxes are attributed to the effect of mutual illumination which heats the surface layers of the illuminated star and does vary not only its bolometric albedo but also its limb-darkening coefficient and gravity-brightening exponent. The analysis of the light curves shows that the effective albedos are generally smaller than that expected from an envelope of convective star, being mostly departed from the theoretical value at the B passband. As the reflected light diminishes the effective temperature and, therefore, the luminosity of the irradiated star increase. The observed bluer U-B colors during primary minimum are attributed to the effects of mutual irradiation and multiple scattering processes which may alter several characteristics of these systems.
This paper presents a photometric and spectroscopic study of the short-period binary star Cl*~Melotte~111~AV~1224. Measurements in the $B$, $V$, and $R$ passbands obtained during three observing runs between 2014 and 2017 and medium-resolution spectra secured in 2014, are analyzed together with public data from the SuperWASP and LAMOST projects. Our light curves show marked asymmetry with a variable OConnell effect. The SuperWASP photometry is used to derive a mean binary period of 0.345225 days. The analysis of the $(O-C)$ diagram reveals that the orbital period is decreasing at a rate of $dP/dt = -3.87 times 10^{-6}$ days yr$^{-1}$, which may be caused by mass transfer from the more-massive component to the less-massive one. The system is found to be a single-lined spectroscopic binary with a systemic velocity, $gamma = 1 pm 3$ Km s$^{-1}$, and a semi-amplitude, K$_{1}$ = 21 $pm$ 5 Km s$^{-1}$. The spectral classification and the effective temperature of the primary component are estimated to be K0V $pm$ 1 and $5200 pm 150$ K, respectively. The photometric and spectroscopic solutions reveal that Cl*~Melotte~111~AV~1224 is a low-mass ratio ($q=m_{2}/m_{1} sim 0.11$), low-inclination ($sim ~ 38^{circ}$) near-contact system. The masses, radii and luminosity for the primary and secondary are estimated to be $1.02 pm 0.06, M_odot$, $1.23 pm 0.05, R_odot $, $1.01 pm 0.06, L_odot$ and $0.11 pm 0.08, M_odot$, $0.45 pm 0.05, R_odot$, $0.10 pm 0.06, L_odot$, respectively. The marginal contact, together with the period decrease, suggests that this binary system may be at a key evolutionary stage, as predicted by the theory of thermal relaxation oscillations.
We study the O-type star HD 161853, which has been noted as a probable double-lined spectroscopic binary system. We secured high-resolution spectra of HD 161853 during the past nine years. We separated the two components in the system and measured their respective radial velocities for the first time. We confirm that HD 161853 is an $sim$1 Ma old binary system consisting of an O8 V star ($M_{rm A,RV} geq 22$ M$_odot$) and a B1--3 V star ($M_{rm B,RV} geq 7.2$ M$_odot$) at about 1.3 kpc. From the radial velocity curve, we measure an orbital period $P$ = 2.66765$pm$0.00001 d and an eccentricity $e$ = 0.121$pm$0.007. Its $V$-band light curve is constant within 0.014 mag and does not display eclipses, from which we impose a maximum orbital inclination $i=54$ deg. HD 161853 is probably associated with an H II region and a poorly investigated very young open cluster. In addition, we detect a compact emission region at 50 arcsec to HD 161853 in 22$mu$m-WISE and 24$mu$m-Spitzer images, which may be identified as a dust wave piled up by the radiation pressure of the massive binary system.
We present the results of the study of the contact binary system BO CVn. We have obtained physical parameters of the components based on combined analysis of new, multi-color light curves and spectroscopic mass ratio. This is the first time the latter has been determined for this object. We derived the contact configuration for the system with a very high filling factor of about 88 percent. We were able to reproduce the observed light curve, namely the flat bottom of the secondary minimum, only if a third light has been added into the list of free parameters. The resulting third light contribution is significant, about 20-24 percent, while the absolute parameters of components are: M1=1.16, M2=0.39, R1=1.62 and R2=1.00 (in solar units). The O-C diagram shows an upward parabola which, under the conservative mass transfer assumption, would correspond to a mass transfer rate of dM/dt = 6.3 times 10-8Modot/yr, matter being transferred from the less massive component to the more massive one. No cyclic, short-period variations have been found in the O-C diagram (but longer-term variations remain a possibility)
Double Periodic Variables (DPV) are among the new enigmas of semi-detached eclipsing binaries. These are intermediate-mass binaries characterized by a long photometric period lasting on average 33 times the orbital period. We present a spectroscopic and photometric study of the DPV V495 Cen based on new high-resolution spectra and the ASAS V-band light curve. We have determined an improved orbital period of $33.492 pm 0.002$ d and a long period of 1283 d. We find a cool evolved star of $M_{2}=0.91pm 0.2 M_{odot}$, $T_{2}= 6000pm 250 K$ and $R_{2}=19.3 pm 0.5 R_{odot}$ and a hot companion of $M_{1}= 5.76pm 0.3 M_{odot}$, $T_{1}=16960pm 400 K$ and $R=4.5pm0.2 R_{odot}$. The mid-type B dwarf is surrounded by a concave and geometrically thick disc, of radial extension $R_{d}= 40.2pm 1.3 R_{odot}$ contributing $sim$ 11 percent to the total luminosity of the system at the V band. The system is seen under inclination $84.!!^{circ}8$ $pm$ $0.!!^{circ}6$ and it is at a distance $d= 2092 pm 104.6$ pc. The light curve analysis suggests that the mass transfer stream impacts the external edge of the disc forming a hot region 11 % hotter than the surrounding disc material. The persistent $V<R$ asymmetry of the H$alpha$ emission suggests the presence of a wind and the detection of a secondary absorption component in He I lines indicates a possible wind origin in the hotspot region.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
