Explore the vast range of titles available.

A re-examination of high-resolution spectral monitoring of the W UMa–type binaries AW UMa and ϵ CrA casts doubt on the widely utilized L. B. Lucy model of contact binaries. The detection of the very faint profile of the secondary component in AW UMa leads to a new spectroscopic determination of the mass ratio, qsp = 0.092 ± 0.007, which is close to the previous, medium-resolution spectroscopic result of T. Pribulla & S. M. Rucinski, qsp = 0.101 ± 0.006, and remains substantially different from a cluster of generally accepted photometric results by several authors, concentrated around qph = 0.080 ± 0.005. A survey of binaries with the best-determined values of the mass ratio shows a common tendency for qph < qsp. The tendency for systematically smaller values of qph may result from the overfilling of the primary lobe and underfilling of the secondary lobe relative to the Roche model geometry, as predicted by the K. Stȩpień model. Despite the observed moderate inter-systemic velocities, the photometric Lucy model may remain useful in providing approximate, though biased, results for the mass ratio. A complicating factor in detailed spectral analysis may be the occurrence of Enhanced Spectral-line Perturbations (ESPs) projected over the secondary profiles, appearing in different numbers in the two studied binaries. The ESPs are tentatively identified within the Stȩpień model as collision fronts or fountains of primary-component gas from the circumbinary, energy-carrying flow.

BRITE-Constellation is devoted to high-precision optical photometric monitoring of bright stars, distributed all over the Milky Way, in red and/or blue passbands. Photometry from space avoids the turbulent and absorbing terrestrial atmosphere and allows for very long and continuous observing runs with high time resolution and thus provides the data necessary for understanding various processes inside stars (e.g., asteroseismology) and in their immediate environment. While the first astronomical observations from space focused on the spectral regions not accessible from the ground it soon became obvious around 1970 that avoiding the turbulent terrestrial atmosphere significantly improved the accuracy of photometry and satellites explicitly dedicated to high-quality photometry were launched. A perfect example is BRITE-Constellation, which is the result of a very successful cooperation between Austria, Canada and Poland. Research highlights for targets distributed nearly over the entire HRD are presented, but focus primarily on massive and hot stars.

Pressure-driven (p-mode) oscillations at the surface of the Sun, resulting from sound waves travelling through the solar interior, are a powerful probe of solar structure, just as seismology can reveal details about the interior of the Earth. Astronomers have hoped to exploit p-mode asteroseismology 1 in Sun-like stars to test detailed models of stellar structure and evolution, but the observations are extremely difficult. The bright star Procyon has been considered one of the best candidates for asteroseismology, on the basis of models and previous reports 2 , 3 , 4 , 5 , 6 , 7 , 8 of p-modes detected in ground-based spectroscopy. Here we present a search for p-modes in 32 days of nearly continuous photometric satellite-based observations of Procyon. If there are p-modes in Procyon, they must have lifetimes less than 2–3 days and/or peak amplitudes <15 parts per million, which defy expectations from the Sun's oscillations and previous theoretical predictions. Target selection for future planned asteroseismology space missions may need to be reconsidered, as will the theory of stellar oscillations.

Essential assumptions and features of the Broadening Function (BF) technique are presented. A distinction between BF determination and the BF concept and utilization is made. The BF's can be determined in various ways. The approach based on linear deconvolution involving stellar templates, as used during the DDO program (1999 – 2008) is described, but the LSD technique would also give excellent results. The BF concept to prove and/or verify photometric light-curve solutions has so far been very limited to only a few W UMa-type binaries, with AW UMa giving particularly unexpected results.

The short-period binary radial velocity program at the David Dunlap Observatory is described in some detail, with a brief summary on its history. The program is now reaching its 100-th orbit, with about 40 more orbits remaining within our access to Northern ( delta < -15), bright <10 mag), short-period(< 1 day) binary systems. All data are processed uniformly using the Broadening Function (BF) formalism which offers best information extraction and permits analysis of heavily rotationally blended spectra. Many close binaries appear to have visual or spectroscopic companions.

Division V on Variable Stars consists of Commission 27, also called Variable Stars, and Commission 42, Close Binary Stars. The former deals with stars whose variations are intrinsic, whereas in the latter the variations are caused by the interactions between the components in the binary or multiple star system. There may be cases where the assignment of an object to one of the two Commissions may be in doubt. For example, the observation of pulsating stars in eclipsing binaries within nearby galaxies, or the relation between some types of oscillation modes and membership to binary systems, continue to be widely discussed.

During the commission business session, the past President presented the new Organizing Committee which was selected by the OC through a e-mail vote conducted during the months before the Rio de Janeiro General Assembly. The new OC will consist of Ignasi Ribas (President), Mercedes Richards (Vice President), and Slavek Rucinski (Past President) with the members: David Bradstreet, Petr Harmanec, Janusz Kaluzny, Joanna Mikolajewska, Ulisse Munari, Panos Niarchos, Katalin Olah, Theo Pribulla, Colin Scarfe and Guillermo Torres.

VLA continuous monitoring of the close, short‐period binary ER Vul during two 11.5 hr sessions in 1995 September in the radio continuum at 3.6 cm (X band) showed a variation pattern similar to that observed in 1990 and 1991, but at a lower mean flux level and with no evidence for a phase dependence, contrary to reports in an earlier paper. Simultaneous observations with theExtreme Ultraviolet Explorerin the 70–140 Å band did not show any significant EUV flaring which would correlate with the radio emission.