Absolute parameters of the Algol binary V505 Sgr from infrared JK light curves

We present the first light curves of V505 Sgr in the infrared (IR) J and K bands. The light curves are analysed with a code based on Roche geometry and stellar model atmosphere fluxes in order to determine a new set of stellar and orbital parameters. From the visual–IR photometry we find no evidence of IR excess in the system. We study the effect of the non-synchronous rotation of the primary star in the light and radial velocity curves. The distance of the system is estimated as  112 ± 4 pc  , in close agreement with the Hipparcos parallax.     

XMM-Newton observation of the eclipsing binary Algol

We present an XMM-Newton observation of the eclipsing binary Algol which contains an X-ray dark B8V primary and an X-ray bright K2IV secondary.The observation covered the optical secondary eclipse and captured an X-ray flare that was eclipsed by the B star.The XMM-Newton European Photon Imaging Camera and Reflection Grating Spectrometer spectra of Algol in its quiescent state are described by a two-temperature plasma model.The cool component has a temperature around 6.4×106 K while that of the hot component...     

Absolute parameters of the newly-identified contact binary star IS Canis Major

This paper presents the results of the first high-resolution spectroscopic observations of the Southern W UMa type system IS CMa. Spectroscopic observations of the system were made at Mt. John University Observatory using a HERCULES fibre-fed échelle spectrograph in September 2007. The first radial velocities of the component stars of the system were determined by using the spectral disentangling technique. The resulting orbital elements of IS CMa are: $a_1\sin i=0.0041\pm 0.0001$ AU, $a_2\sin i=0.0135\pm 0.0001$ AU, $M_1{\sin }^{3}i=1.48\pm 0.01{\mathrm{M}}_{\odot }$, and $M_2{\sin }^{3}i=0.44\pm 0.01{\mathrm{M}}_{\odot }$. The components were found to be in synchronous rotation taking into account the disentangled ${\mathrm{H}}_{\delta }$ line profiles of both components of the system. The Hipparcos light curve was solved by means of the Wilson–Devinney method supplemented with a Monte Carlo type algorithm. The radial velocity curve solutions including the proximity effects give the mass ratio of the system as 0.297 ± 0.001. The combination of the Hipparcos light and radial velocity curve solutions give the following absolute parameters of the components: $M_1=1.68\pm 0.04{\mathrm{M}}_{\odot }\text{,}{\mathrm{M}}_2=0.50\pm 0.02{\mathrm{M}}_{\odot }\text{,}{R}_1=2.00\pm 0.02{\mathrm{R}}_{\odot }\text{,}{R}_2=1.18\pm 0.03R_{\odot }\text{,}{L}_1=7.65\pm 0.60$ ${\mathrm{L}}_{\odot }$ and $L_2=1.99\pm 0.80{\mathrm{L}}_{\odot }$. The distance to IS CMa was calculated as $87\pm 5$ pc using the distance modulus with corrections for interstellar extinction. The position of the components of IS CMa in the HR diagram are also discussed: the system seems to have an age of 1.6 Gyr.     

Algol,a multiple “binary”

Eight campaigns of Algol suggest that a fourth body is possible after all in this triple system of a binary star.     

A model of the Algol type close binary TT hydrae

UBV photometric observations and elements of TT Hydrae obtained by Kulkarni and Abhyankar (1980) are combined with the radial velocity curve of Popper (1979, personal communication) to derive the absolute dimensions and. a model of this important Algol system. While the photometric ratios of radii inV andB are in agreement givingk = 0.3812 for a limb darkening coefficient ofx = 0.6, application of Irwin’s (1947) method givesx = 0.4 forU. The primary is found to be a main sequence Al V star of mass 2.61M _⊙ and radius 2.01 R_⊙, and the secondary is classified as a Kl III star of mass 0.70M _⊙ and radius 5.33R _⊙. The observed Fourier coefficients for the light outside the eclipse agree with those calculated from theory for the reflection and ellipticity effects. The system shows an ultraviolet excess of 0.5 to 0.6 magnitudes during primary eclipse, which is attributed to an asymmetric circumstellar distribution of matter around the primary. The evolutionary status of the secondary, which does not appear to fill its Roche lobe completely, is discussed.     

Further confirmations of mass transfer in Algol type binary U Sagittae

This paper describes how a new photometric V light curve solution of Algol type binary U Sge was obtained using Wilson–Devinney code. I also discuss how the physical and orbital parameters, along with absolute dimensions of the system, were determined. The Roche lobe configurations of the system indicate that the secondary component has filled its Roche lobe and therefore is losing mass at the rate of 6.15×10⁻⁷ M _sun yr⁻¹. The conservative mass flow is the most likely process in this system.     

Photometric and spectroscopic investigation of the oscillating Algol type binary: EW Boo

We obtained the physical and geometrical parameters of the EW Boo system, which exhibits short period and small amplitude pulsations as well as brightness variations due to orbital motion of components. Towards this end we carried out photometric observations at Ankara University Kreiken Observatory (AUKO) as well as spectroscopic observations at TUBITAK National Observatory (TNO). The light and radial velocity curves obtained from these observations have been simultaneously analyzed with PHOEBE and the absolute parameters of the system along with the geometric parameters of the components have been determined. Using model light curves of EW Boo, light curve regions in which the pulsations are active have been determined and as a result of analyses performed in the frequency region, characteristic parameters of pulsations have been obtained. We find that the results are compatible with current parameters of similar systems in the literature. The evolutionary status of the components is propounded and discussed.     

Absolute and geometric parameters of the W UMa‐type contact binary V404 Pegasi

We present the results of our investigation of the geometrical and physical parameters of the W UMa‐type binary V404 Peg from analysis of CCD (BVRI) light curves and radial velocity data. The photometric data were obtained during 2010 at Ankara University Observatory (AUO). Light and radial velocity observations were analyzed simultaneously by using the well‐known Wilson‐Devinney (2007 revision) code to obtain absolute and geometrical parameters. Our solution indicates that V404 Peg is an A‐type overcontact binary with a mass ratio of q = 0.243 and an overcontact degree of f = 32.1 %. Combining our light curves with the radial velocity curves from Maciejewski & Ligeza (2004), we determined the absolute parameters of this system as follows: a = 2.672 R_⊙, M₁ = 1.175 M_⊙, M₂ = 0.286 M_⊙, R₁ = 1.346 R_⊙, and R₂ = 0.710 R_⊙. Finally, we discuss the evolutionary condition of the system (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Absolute parameters of the close binary BW Boo with a superasynchronous A2m primary component

Based on two high-dispersion spectra of the close binary BW Boo, we have detected lines of the secondary component whose contribution to the combined spectrum does not exceed 2%. We have determined the rotation velocities of the components and spectroscopic orbital elements. Numerous lines of neutral and ionized iron have been used to determine the effective temperature and surface gravity for the primary component. The photometric light curves for this binary have been solved for the first time. Its primary component is an A2Vm star with a mass of 2 ± 0.1M _⊙ and a radius of 1.9 ± 0.4R _⊙. Its rotation velocity is 2 km s⁻¹, which is a factor of 18 lower than the pseudo-synchronous velocity for this component. The G6 secondary component, a T Tau star, has a rotation velocity of 17 km s⁻¹, amass of 1.1M _⊙, and a radius of 1 R _⊙. The age of the binary has been estimated to be 10⁷ yr.     

Absolute properties of the overcontact binary HH Boo

We obtained multi-colour light curves of the overcontact binary system HH Boo and analysed the orbital period variation of the system. Our analysis tentatively indicates either mass transfer from the secondary to the primary or mass loss from the system at a rate of -5.04 × 10⁻⁷ M_⊙ per year. Through a combined analysis of the published radial velocity curve and light curves, we determined an inclination (i) of 69°.71 ± 0°.16 and a semi-major axis (a) of 2.246 ± 0.064 R_⊙ for HH Boo. The masses of the primary and secondary components were found to be 0.92 ± 0.08 M_⊙ and 0.58 ± 0.06 M_⊙, respectively. The radius determined for the primary was 0.98 ± 0.03 R_⊙, while that determined for the secondary was 0.80 ± 0.02 R_⊙. We demonstrated that HH Boo is most likely a member of the A-type subclass of W UMa binaries.     

Absolute parameters and observed flares in the M-type detached eclipsing binary 2MASS J04100497+2931023

The eclipsing binary 2 MASS J04100497+2931023(J04100497+2931023) is classified its spectral type of M0±2 V on basis of a low-resolution spectral survey by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST). The low-resolution spectra exhibit strong single-peak emission in the Hα line. We obtained the radial velocities of this binary by means of the Cross-Correlation Function method from the LAMOST medium-resolution spectra. Both components of J04100497+2931023 indicate strong emissions in the Hα line. We performed follow-up photometric observations of J04100497+2931023 using the Xinglong 85 cm telescope of National Astronomical Observatories, Chinese Academy of Sciences. We obtained its full light curve in V RI filters. We first determined their absolute parameters from simultaneously radial velocity and light curves by the Wilson-Devinney program. From our new light curves, we detected three flares for the first time, including one convective flare. The amplitudes,durations, energies, and spectral indices of three flares were also determined. J04100497+2931023 was monitored for approximately 29 h, which indicates that the flare rate is 0.1 flare per hour. We conclude that J04100497+2931023 is a low-mass detached eclipsing binary with strong magnetic activity.     

Absolute and geometric parameters of W UMa type contact binary TYC 1174-344-1

We present the results of our investigation on the geometrical and physical parameters of W UMa-type binary TYC1174-344-1 from analyzed CCD (BVRI) light curves and radial velocity data. The photometric data were obtained in 2009 at Ankara University Observatory (AUO) and the spectroscopic observations were made in 2008 at Astrophysical Observatory of Asiago (Italy). Light and radial velocity observations were analyzed simultaneously by using the well-known Wilson–Devinney (2007 revision) code to obtain absolute and geometrical parameters. According to our solutions, the system is found to be a low mass-ratio A-type W UMa system. Combining our photometric solution with the spectroscopic data, we derived mass and radii of the eclipsing system as M₁ = 1.381 M_⊙, M₂ = 0.258 M_⊙, R₁ = 1.449 R_⊙ and R₂ = 0.714 R_⊙. We finally discussed the evolutionary condition of the system.     

Photospheric and chromospheric activity of the short period X-ray and Algol eclipsing binary UX CrB

We present six \(\mbox{V}R_{c}I_{c}\) light curves of UX CrB from observations carried out from 2011–2015. We also obtained three optical spectra using the 2.16-m optical telescope and LAMOST survey at the national astronomical observatories. We classified its spectral type as \(\mbox{G2}\pm\mbox{2V}\). We noticed that there are strong absorptions in the H_α, H_β, Ca ii H&K and infrared triplet lines in the observed spectra. By subtracting away the photospheric contribution, we also noticed that there are small excess emissions in these chromospheric active lines, which indicate there are weak chromospheric activities. We tried and obtained four photometric solutions with different spot positions from our full and high time-resolution light curves in 2012, using the updated Wilson-Devinney code. The model with two spots on the primary produced the best result for explaining the observed light curves from 2012. Moreover, we explained all other light curves based on our photometric solution using our 2012 light curves. There are two active longitudes at about 68^° and 255^°. We noticed that the starspots have both long-time (years) and short-time (about two months) variation by analyzing the light curves and its starspot parameters. There is also an obvious oscillation of light curve maximum between 0.25 and 0.75 phases by analyzing the values of \(\mbox{Max.~I} - \mbox{Max.~II}\). We conclude UX CrB are the evolved main-sequence stars with strong photometric and chromospheric activities.