The precision of observations using observatories in space exceeds by a factor of 100 the accuracy of the light curve and line profile synthesis methods developed decades ago. Furthermore, physical effects too small to detect using ground based observations, such as aberration and Doppler beaming, become important when observing from space.

The GDDSYN method, developed by Hendry and Mochnacki, is both accurate and efficient, and is useful in the new context of space-based observations. Using a geodesic distribution of triangular surface elements varying little in size, it provides an alternative to the Wilson-Devinney code used at the heart of PHOEBE, and is adaptable to the new physical effects which are now observable. Tests and improvements are discussed.

Program SHELLSPEC is designed to calculate light-curves, spectra and images of interacting binaries and extrasolar planets immersed in a moving circumstellar environment which is optically thin. It solves simple radiative transfer along the line of sight in moving media. The assumptions include LTE and optional known state quantities and velocity fields in 3D. Optional (non)transparent objects such as a spot, disc, stream, jet, shell or stars may be defined (embedded) in 3D and their composite synthetic spectrum calculated. The Roche model can be used as a boundary condition for the radiative transfer. Recently, a new model of the reflection effect, dust and Mie scattering were incorporated into the code.

ϵ Aurigae is one of the most mysterious objects on the sky. Prior modeling of its light-curve assumed a dark, inclined, disk of dust with a central hole to explain the light-curve with a sharp mid-eclipse brightening. Our model consists of two geometrically thick flared disks: an internal optically thick disk and an external optically thin disk which absorbs and scatters radiation. Shallow mid-eclipse brightening may result from eclipses by nearly edge-on flared (dusty or gaseous) disks. Mid-eclipse brightening may also be due to strong forward scattering and optical properties of the dust which can have an important effect on the light-curves.

There are many similarities between interacting binary stars and transiting extrasolar planets. The reflection effect which is briefly reviewed is one of them. The exact Roche shape and temperature distributions over the surface of all currently known transiting extrasolar planets have been determined. In some cases (HAT-P-32b, WASP-12b, WASP-19b), departures from the spherical shape can reach 7-15%.

We present here the systematic study of the chemical abundances of Am stars in order to search for possible abundance anomalies driven by tidal interaction in these binary systems. These stars were put into the context of Am binaries with 10 < Porb < 180 d and their abundance anomalies discussed in the context of possible tidal effects. There is clear anti-correlation of the Am peculiarities with v sin i. However, there seems to be also a correlation with eccentricity and orbital period.

The RV analysis tool integrates widely used methods of radial velocity determination (CCF, TODCOR, BF) in an easy to use graphical environment. No advanced knowledge of these methods is required to use it. The obtained velocities may be immediately analyzed with the same tool as it comprises flexible fitting of orbital parameters, which includes the third body influence and pulsational velocities of the components. These features together help to establish the most accurate combination of templates, spectrum range, and method. Scripting functionality is to be implemented in the future.

We present a new observational project to study the hierarchical triple stellar system Algol, concentrating on the semidetached eclipsing binary at the heart of the system. Over 140 high-resolution and high-S/N spectra have been secured, of which 80 are from FIES at the Nordic Optical Telescope, La Palma, and the remainder were obtained with BOES at the Bohyunsan Optical Astronomy Observatory in Korea. All three components were successfully detected by the method of spectral disentangling, which yields the individual spectra of the three stars and also high-quality spectroscopic elements for both the inner and outer orbits. We present a detailed abundance study for the mass-accreting component in the inner orbit, which holds information on the history of mass transfer in the close inner binary system. We also reveal the atmospheric parameters and chemical composition of the tertiary component in the outer orbit.

Infinity is a new program for modeling binary systems. The model is based on Roche geometry with asynchronous rotation, including an assortment of effects like gravity and limb darkening, mutual irradiation, bright and dark spots and so on. However, Infinity brings innovations in the modeling of accretion disks, and introduces the modeling of radial and non-radial oscillations on one or both components of the system.

At this stage of development, Infinity can produce light curves, spectra and radial velocity curves; solving the inverse problem is still a work in progress. In terms of programming, Infinity is being developed in the object-oriented language C#, and great care is taken to produce readable, easily extensible and verifiable code. Infinity is fully optimized to take advantage of modern multi-core CPUs, and the code is thoroughly covered with unit-tests. We expect to make a public release during 2012.

We present fundamental parameters of four massive eclipsing binaries in the young massive cluster Westerlund 1. The goal is to measure accurate masses and radii of their component stars, which provide much needed constraints for evolutionary models of massive stars. Accurate parameters can further be used to determine a dynamical lower limit for the magnetar progenitor and to obtain an independent distance to the cluster. Our results confirm and extend the evidence for a high mass for the progenitor of the magnetar.

V2028 Cyg shows a B[e] phenomenon. Due to the presence of both cool (K7III) and hot (B4III) components in the spectra, it is supposed to be a binary. Our modelling of the time variability of Hα line bisectors shows, however, that this hybrid spectrum can originate in one star, which is surrounded by a disc.

MY Ser is an eclipsing early-type contact system. Both components are of spectral type O6 III. Using ESO archive spectra, we show that the radial velocity of the third body, which contributes about half of the total luminosity, changed from 2006 to 2009. The line profiles of the eclipsing system have peculiar shapes and strengths; namely around conjunctions, they are affected by circumbinary matter.

New CCD photometric observations of SZ Her were obtained between February and May 2008. More than 1,100 times of minimum light spanning more than one century were used for the period analysis. We find that the orbital period of SZ Her has varied due to a combination of two periodic variations, with cycle lengths of P3 = 85.8 yr and P4 = 42.5 yr and semi-amplitudes of K3 = 0.013 days and K4 = 0.007 days, respectively. The most reasonable explanation for them is a pair of light-time-travel (LTT) effects driven by the existence of two M-type companions with minimum masses of M3 = 0.22 M⊙ and M4 = 0.19 M⊙, located at nearly 2:1 mean motion resonance. Then, SZ Her is a quadruple system and the 3rd and 4th components would stay in the stable orbital resonance.

We modeled the broad wings of the OVI 1032,1038Å resonance lines and HeII 1640Å line in the spectra of some symbiotic stars by the electron-scattering process. We determined an empirical relationship between the emission measure of the symbiotic nebula and the electron optical depth. This allowed us to determine a contribution from the electron-scattering also to emission lines, which originate in a more extended, low density part of the nebula. For example, subtracting the electron-scattering contribution from the Hα line profile makes it possible to determine more precisely the mass loss rate via the wind from the hot star in symbiotic binaries.

V393 Scorpii is a bright Galactic Double Periodic Variable showing a long photometric cycle of ≈253 days. The ASAS V-band light curve has been disentangled into an orbital and long cycle component. The orbital light curve was modeled with two stellar components and a circumprimary accretion disk. Based on this model, and the careful choice of a template spectrum for the donor, the contribution of the donor to the line+continuum spectrum was removed at every orbital phase. The remaining residual spectra were analyzed. Notable findings are the larger line emissivity observed during the long cycle maximum that is concentrated to low velocities and the presence of discrete absorption components in the wings of the OI 7773 line, whose visibility strongly depends on the orbital phase. In addition, weak emission is observed in donor metallic absorption lines. Finally, we present the first Hα Doppler map for V 393 Scorpii. A modulated wind explains many observational features.

There are several types of binary stars which show non-periodical radial velocity variations with the amplitude larger than those connected with the orbital motion. The non-periodical changes have to be removed in order to study the orbital ones. We propose three removal techniques, two of which are based on the trend modeling with continuous functions and the third one that takes the orbital motion into account.

Thanks to OGLE, Kepler, CoRoT and planned new ambitious survey projects, the eclipsing binary (EB) community is beginning to experience a long-predicted data deluge. Beyond the analysis of the many fascinating individual objects yielded by these programs, these complete datasets themselves should yield further insights. Because objects in such datasets are characterized by many parameters, tools that assist in understanding high-dimensional data are acquiring increasing relevance. Chiefly among these are new Advanced Visualization (AV) tools and various methods of clustering data, both approaches complementing each other naturally. We illustrate the use of these tools as applied to OGLE II LMC EB data and respective EBAI light curve solutions.

Recent studies of the Algol-type binary RY Per presented strong evidence that there is an accretion disk around the primary in the system. We used new UBV photometry from Hvar Observatory and the BINSYN software package in order to determine the basic parameters of the disk. The search for the best parameter set was performed with a fully automated steepest descent method. The resulting disk is large and visible at all orbital phases. Somewhat surprising is the large mass transfer rate which should be tied with, currently unreported, secular period changes.

The light curves of many Algol-type binary stars are complicated with strange variations. Secular variations are due to the transient nature of the accretion structure, while the phase-dependent features, such as outside-of-eclipse dips, are likely geometrical effects of the accretion structure eclipsing the primary star. Presented here is a model of the ultraviolet light curve of R Arae that explains these variations through the combination of an eccentric accretion structure and the system's orbital inclination.

The orbital period of R Ara is 4.4 days, which is too long to allow for direct impact of the mass transfer stream onto the primary star, but not long enough for a stable accretion disk to form. Such intermediate-period Algols are good candidates in which to find transient and eccentric accretion structures. Other examples of interacting Algols that exhibit outside-of-eclipse dips in their light curves include RV Oph (Porb.=3.7 days) and Y Psc (Porb.=3.9 days).

In order to more accurately model eccentric accretion structures with synthetic light curves, especially at visible (and longer) wavelengths, more work must be done to account for emission by the parts of the accretion structure that are not in the line of sight to the primary star. The model presented here accounts only for the eclipsing regions of the accretion structure.

We present physical parameters for the detached eclipsing binary KIC3858884 which has a δ-Scuti type pulsating secondary component. To derive orbital elements from the radial-velocity curve, high resolution Echelle spectra were obtained at the Bohyunsan Optical Astronomy Observatory in Korea. The BOES spectra and Kepler photometric data were analyzed with well-known codes: JKTEBOP and Wilson-Devinney model for eclipsing light-curve synthesis, and Period04 for pulsation frequency analysis. After the iterative curve fitting, we determined the physical parameters of KIC3858884 as M1=2.02 ± 0.23M⊙, M2=2.02 ± 0.16M⊙, R1=3.61 ± 0.12R⊙, R2=2.84 ± 0.10R⊙, respectively.

We improved the method of light curve analysis for large numbers of eclipsing binaries. Current methods require a week to analyze the light curves of an eclipsing binary for its physical and orbital parameters. Therefore, we developed a new method to treat large numbers of light curves of eclipsing binaries. We tested the new method by analyzing more than 14 hundred light curves and 9 hundred light curves discovered by OGLE in the Small Magellanic Cloud and Galactic center, respectively.

We present the results of space-based photometric and ground-based spectroscopic observing campaigns on the γ-ray binary LS 5039. The new orbital and physical parameters of the system are similar to former results, except we found a lower eccentricity. Our MOST-data show that any broad-band optical photometric variability at the orbital period is below the 2 mmag level. Light curve simulations support the lower value of eccentricity and imply that the mass of the compact object is higher than 1.8 M⊙.

The small group of λ Bootis stars comprises late B to early F-type stars, with moderate to extreme (up to a factor 100) surface under-abundances of most Fe-peak elements and solar abundances of lighter elements (C, N, O, and S). The main mechanisms responsible for this phenomenon are atmospheric diffusion, meridional mixing, and accretion of material from their surroundings. Especially spectroscopic binary (SB) systems with λ Bootis-type components are very important to investigate the evolutionary status and accretion process in more details. Because also δ Scuti type pulsation was found for several members, it gives the opportunity to use the tools of astroseismology for further investigations. We present the results of our long term efforts of detailed abundance analysis, orbital parameter estimation and photometric time series analysis for five well investigated SB systems.