We present a catalog of photometric and spectroscopic data collected during and around of EE Cep eclipses in 1997, 2003 and 2008/9. The photometric data were obtained with 25 different instruments, mainly in Johnson-Cousins UBV(RI)C bands, and some small sets of the data were obtained with narrow interference filters, placed on, or around of H-alpha and H-beta lines. The photometry from the last two eclipses have been compiled into the set of consistent photometric data in UBV(RI)C bands, that has been used in the paper to modelling of the eclipses in EE Cep system. The 100 of spectra released in this catalog were obtained with 8 of different spectrographs at low, medium and high resolutions (R in range ~2000-48000). About half of them (54 spectra) cover narrow ranges of order 200 Angstroms with H-alpha, H-beta lines or NaI dublet, and the second part (46 spectra) cover longer ranges of wavelengths - several thousands of Angstroms in the visual domain or in the near infrared. (7 data files).

Context. EE Cep is an unusual long-period (5.6 yr) eclipsing binary discovered during the mid-twentieth century. It undergoes almost-grey eclipses that vary in terms of both depth and duration at different epochs. The system consists of a Be type star and a dark dusty disk around an invisible companion. EE Cep together with the widely studied ɛ Aur are the only two known cases of long-period eclipsing binaries with a dark, dusty disk component responsible for periodic obscurations. Aims: Two observational campaigns were carried out during the eclipses of EE Cep in 2003 and 2008/9 to verify whether the eclipsing body in the system is indeed a dark disk and to understand the observed changes in the depths and durations of the eclipses. Methods: Multicolour photometric data and spectroscopic observations performed at both low and high resolutions were collected with several dozen instruments located in Europe and North America. We numerically modelled the variations in brightness and colour during the eclipses. We tested models with different disk structure, taking into consideration the inhomogeneous surface brightness of the Be star. We considered the possibility of disk precession. Results: The complete set of observational data collected during the last three eclipses are made available to the astronomical community. The 2003 and 2008/9 eclipses of EE Cep were very shallow. The latter is the shallowest among all observed. The very high quality photometric data illustrate in detail the colour evolution during the eclipses for the first time. Two blue maxima in the colour indices were detected during these two eclipses, one before and one after the photometric minimum. The first (stronger) blue maximum is simultaneous with a "bump" that is very clear in all the UBV(RI)C light curves. A temporary increase in the I-band brightness at the orbital phase ~0.2 was observed after each of the last three eclipses. Variations in the spectral line profiles seem to be recurrent during each cycle. The Na i lines always show at least three absorption components during the eclipse minimum and strong absorption is superimposed on the Hα emission. Conclusions: These observations confirm that the eclipsing object in EE Cep system is indeed a dark, dusty disk around a low luminosity object. The primary appears to be a rapidly rotating Be star that is strongly darkened at the equator and brightened at the poles. Some of the conclusions of this work require verification in future studies: (i) a complex, possibly multi-ring structure of the disk in EE Cep; (ii) our explanation of the "bump" observed during the last two eclipses in terms of the different times of obscuration of the hot polar regions of the Be star by the disk; and (iii) our suggested period of the disk precession (~11-12 Porb) and predicted depth of about 2 m for the forthcoming eclipse in 2014. Appendix A is available in electronic form at http://www.aanda.orgTables B.1-B.36 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/544/A53

VFTS 682, a very massive and very hot Wolf-Rayet (WR) star recently discovered in the Large Magellanic Cloud near the famous star cluster R136, might be providing us with a glimpse of a missing link in our understanding of Long Gamma-Ray Bursts (LGRBs), including dark GRBs. It is likely its properties result from chemically homogeneous evolution (CHE), believed to be a key process for a massive star to become a GRB. It is also heavily obscured by dust extinction, which could make it a dark GRB upon explosion. Using Spitzer data we investigate the properties of interstellar dust in the vicinity of R136, and argue that its high obscuration is not unusual for its environment and that it could indeed be a slow runaway (``walkaway'') from R136. Unfortunately, based on its current mass loss rate, VFTS 682 is unlikely to become a GRB, because it will lose too much angular momentum at its death. If it were to become a GRB, it probably would also not be dark, either escaping or destroying its surrounding dusty region. Nevertheless, it is a very interesting star, deserving further studies, and being one of only three presently identified WR stars (two others in the Small Magellanic Cloud) that seems to be undergoing CHE.

We discuss the origin and evolution of low mass contact binaries with Porb shorter than 0.3 d that have properties somewhat different from the rest of the contact binaries. A comparison of an evolutionary model set with observations shows that both components are on the main sequence, the age of the binaries is at least several Gyr, while the contact phase lasts only less than 1 Gyr.

The results from a four-year systematic observational sky survey of eclipsing binaries, candidates for containing a delta Scuti component, are presented. More than a hundred systems were tested for a possible oscillating behavior, 17 out of which were found to show evidence of pulsating component and 8 more being ambiguous cases for further research. Data analysis and modelling methods are described step-by-step, and as an example the case of BO Her is presented in detail. Using the observational results of all known close binaries with a delta Scuti component collected from the literature and our own study, a total of 73 such systems is gathered. Correlations among their physical parameters (e.g. pulsation and orbital periods, evolutionary status) are also derived, extending significantly our knowledge of these systems.