Related papers: Observational constraints on massive binaries
I present an overview of the techniques used for detecting and following up binaries in nearby galaxies and present the current census of extragalactic binaries, with a focus on eclipsing systems. The motivation for looking in other…
Binarity is often invoked to explain peculiarities that can not be explained by the standard theory of stellar evolution. Detecting orbital motion via the Doppler effect is the best method to test binarity when direct imaging is not…
The origin of chemically peculiar stars remains enigmatic, especially regarding their frequency among their "normal" peers. In addition to magnetic fields and rotation, multiplicity may shed light on the question. We mention the main…
Physical collisions between stars occur frequently in dense star clusters, either via close encounters between two single stars, or during strong dynamical interactions involving binary stars. Here we study stellar collisions that occur…
Binary stars have been shown to have a substantial impact on the integrated light of stellar populations, particularly at low metallicity and early ages - conditions prevalent in the distant Universe. But the fraction of stars in stellar…
Cepheids provide approaches to determining binary parameters which are often complementary to those for main sequence massive and intermediate mass stars. Specifically, we are using high resolution imaging, radial velocities, and X-ray…
Magnetic fields are considered to be key components of massive stars, with a far-reaching impact on their evolution and ultimate fate. A magnetic mechanism was suggested for the collimated explosion of massive stars, relevant for…
A brief summary of properties of the contact binaries is presented, with the goal to stress the unsolved problems of their formation and evolution as well as their potential contribution to studies of Galactic stellar populations. The first…
We have attempted to establish an observational evidence for presence of distant companions which may have acquired and/or absorbed the angular momentum during evolution of multiple systems thus facilitating or enabling formation of contact…
Symbiotic stars are long-period interacting binary systems in which an evolved red giant star transfers material to its much hotter compact companion. Such a composition places them among the most variable stars. In addition to periodic…
A number of efforts are underway to detect close binary stars in planetary nebulae. The primary goal of these studies is to determine the binary fraction of central stars. The next stage is a detailed analysis of the binaries to determine…
Theoretically, bound binaries of massive black holes are expected as the natural outcome of mergers of massive galaxies. From the observational side, however, massive black hole binaries remain elusive. Velocity shifts between narrow and…
Our understanding of massive stars remains incomplete. Many high-z galaxies and nearby analogs exhibit strong He II emission, indicating an abundance of photons with energies >54.4 eV that standard single-star population models cannot…
Close binary central stars of planetary nebulae are key in constraining the poorly-understood common-envelope phase of evolution, which in turn is critical in understanding the formation of a wide-range of astrophysical phenomena (including…
Multiplicity is ubiquitous among massive stars. While the stellar components usually display similar masses, some binaries with extremely low mass ratios were also observed. Some of them are primordial, while others arise from binary…
In spite of the almost all-encompassing variability of Be stars, surveys play a steadily increasing role in complementing the insights gained from single-star studies. The definition of classical Be stars as recently augmented by…
Magnetars form a special population of neutron stars with strong magnetic fields and long spin periods. About 30 magnetars and magnetar candidates known currently are probably isolated. But the possibility that magnetars are in binaries…
Binaries that merge within the local Universe originate from progenitor systems that formed at different times and in various environments. The efficiency of formation of double compact objects is highly sensitive to metallicity of the star…
We estimate the observed distribution of chirp masses of compact object binaries for the gravitational wave detectors. The stellar binary evolution is modeled using the {\em StarTrack} population synthesis code. The distribution of the…
We analyze the currently available observations of X-ray binaries in a consistent way, to re-determine the masses of the neutron stars in these systems. In particular, our attention is focussed on a realistic and consistent assessment of…