The Gaia-ESO Survey (GES, Gilmore et al. 2012) provides a unique opportunity to detect spectroscopically multiplicity among different populations of the Galaxy using the cross-correlation functions (CCFs). We present here the GES internal Data Release 4 (iDR4) results of the detection of double, triple and quadruple-line spectroscopic binary candidates (SBs) and discuss some peculiar systems.

In this contribution the focus is on post-AGB binaries. It is now well established that these are often surrounded by stable long-lived circumbinary discs of gas and dust. Here we introduce our monitoring programme with our high-resolution spectrograph HERMES mounted on the 1.2m Mercator telescope. We illustrate the use of time-series high-resolution spectra and show that jets observed in many systems are launched at the location of the companion. The jet is likely originating from a circum-companion accretion disc. The link of these systems to some PNe relies on the detection of similar orbits and hence wide spectroscopic orbits among central stars of PNe. The conclusion is that Keplerian discs as well as circum-companion discs are fundamental to understanding the properties and evolution of these interacting evolved binaries.

Mass discrepancy is one of the problems that is pending a solution in (massive) binary star research field. The problem is often solved by introducing an additional near core mixing into evolutionary models, which brings theoretical masses of individual stellar components into an agreement with the dynamical ones. In the present study, we perform a detailed analysis of two massive binary systems, V380 Cyg and σ Sco, to provide an independent, asteroseismic measurement of the overshoot parameter, and to test state-of-the-art stellar evolution models.

The Red Rectangle is a spectacular bipolar nebula centred around the eccentric evolved binary HD 44179. The nebula is rich in spectral signatures: it is the brightest source of the Extended Red Emission (ERE), of the Blue Luminescence (BL) as well as one of the brightest sources of mid-IR PAH bands. Moreover, and unique to this source, a plethora of narrow emission lines is detected on top of the diffuse ERE. Some of these molecular features show rotational contours which become narrower at larger angular separation from the central engine. Some converge to wavelengths and profiles of narrow DIBs. All these observations show that the Red Rectangle is a very rich laboratory to study active astrochemical processes within the nebula. We also address, but fail to answer, the question why this source is so unique among the many observed post-AGB binary analogues.

We review the possible formation and orbital stability of Earth-mass or super Earth-mass planets around either of the stars Alpha Centauri A or B and describe a program at Mt John University Observatory using the Doppler method that aims to detect such planets. From New Zealand, we are able to observe the Alpha Centauri system year-round. This is critical in order to acquire data of sufficient quantity and phase coverage to detect the orbit of a terrestrial-mass planet in the habitable zone. Our observations are being made at high resolution (R = 70,000) and high signal-to-noise with the Hercules vacuum echelle spectrograph attached to the 1-m McLellan telescope by a 25-m long optical fibre and using an iodine cell. We discuss the velocity precision and instrumental stability required for success and outline the progress of the observations so far. At present we are collecting about 10,000 observations of each star, A and B, per year with a typical precision of 2.5 m/s per observation.

In this summary, I address the next generation of theoretical tools with which it may be necessary to interpret the data anticipated as both stellar and planetary astronomy enter their next decades.

The study of eclipsing binaries as members of multiple systems can provide us important information about their origin, evolution, mutual inclination of the orbits, independent distance and mass determination, as well as the stellar multiplicity in general. We are carrying out a long-term photometric monitoring of several eclipsing binaries within the visual multiples and, besides the complete light curves, we are trying to detect the period changes due to the orbital motion around a common barycenter.

Systems like DN UMa, V819 Her, LO Hya, or VW Cep are typical examples of eclipsing binaries orbiting around the barycenter of the multiple system, while their respective periods are on the order of years or decades. However, the expected period variation is only hardly detectable and there is still uncertainty about which of the components is the eclipsing one. Precise spectroscopy would be of great benefit, but detecting the changes in the gamma velocity is still problematic, and spectral disentangling of such complicated systems like sextuple VV Crv (periods 1.46, 3.14, and 44.51 days) is also rather difficult. However, the detection of the changing depths of the eclipses in the latter system would be interesting.

It is believed that CVs do not produce jets unlike other, more massive interactive binaries. Here we present spectrophotometric observations of the super-outburst of V455 And. We show here that a strong wind perpendicular the the accretion disc at the maximum of the super-otburst, i.e a jet, can probably explain the observed spectroscopic behavior of this system.

As recent observations have shown, luminous, hydrogen-rich WN5-7h stars (and their somewhat less extreme cousins, O3f/WN6 stars) are the most massive main-sequence stars known. However, not nearly enough very massive stars have been reliably weighed to yield a clear picture of the upper initial-mass function (IMF). We therefore have carried out repeated high-quality spectroscopy of four new O3f/WN6 and WN5-7h binaries in R136 in the LMC with GMOS at Gemini-South, to derive Keplerian orbits for both components, respectively, and thus to directly determine their masses. We also monitored binary candidates and other, previously unsurveyed stars, to increase the number of very massive stars that can be directly weighed.

Innovative work on close binary models in 2003-06 improved upon synthesized line spectra, line profiles, and polarimetry; developed new ways of parameter estimation; and increased solution effectiveness and efficiency. Recent applications demonstrate the analytic power of binary system line spectrum models that pre-date the triennium. X-ray binary line profiles and radial velocity curves were refined by solution of the radiative transfer problem with specific inclusion of X-irradiation. Model polarization curves were generated by Monte Carlo experiments with multiple Thomson scattering in thin and thick binary system disks. In the parameter estimation area, independent developments by two groups now allow measurement of ephemerides, apsidal motion, and third body parameters from whole light and velocity curves, to supplement the traditional way of eclipse timings. Although the new route to those parameters is not well known within the ephemeris community, there are accuracy advantages and the number of applications is increasing. Numerical solution experiments on photometric mass ratios have checked two views of their intuitive basis, and show that mass ratios are well determined where star radii and limiting lobe radii are both well determined, which is for semi-detached or over-contact binaries with total-annular eclipses. Solution efficiency and automatic operation is needed for processing of light curves from large surveys, and will also be valuable for preliminary solutions of individually observed binaries. Neural networks have mainly been used for classification, and now a neural network program reliably finds preliminary solutions for W UMa binaries. Archived model light curves and Fourier fitting also are being pursued for classification and for preliminary solutions. Light curves in physical units such as erg·sec−1·cm−3 now allow direct distance estimation by combining the absolute accuracy of model stellar atmospheres with the astrophysical detail of a physical close binary model, by means of rigorous scaling between surface emission and observable flux. A Temperature-distance (T-d) theorem specifies conditions under which temperatures of both stars and distance can be found from light and velocity curves.

The method of spectra disentangling has been applied in many studies of different stellar systems up to the distance of Andromeda Galaxy. In some of these applications the underlying assumptions are not precisely satisfied. This is why new generalizations of the method are needed. Ways to overcome these problems are discussed here.

The method of spectra disentangling has been applied in many studies on different stellar systems up to the distance of Andromeda Galaxy. In some of these applications the underlying assumptions are not precisely satisfied. This is why new generalizations of the method are needed. Ways to overcome these problems are discussed here.