Related papers: A stringent upper limit on Be star fractions produ…
Stars are commonly formed in binary systems, which provide a natural laboratory for studying planet formation in extreme conditions. In our first paper (Paper I) of a series Xie et al. (2011), we have shown that the intermediate stage -…
Recent observations of binary stars in the Galactic field show that the binary fraction and the mean orbital separation both decrease as a function of decreasing primary mass. We present $N$-body simulations of the effects of dynamical…
Populations of massive stars are directly reflective of the physics of stellar evolution. Counting subtypes of massive stars and ratios of massive stars in different evolutionary states have been used ubiquitously as diagnostics of age and…
The majority of massive classical Be stars are thought to be binary interactions products. Their rapid rotation and often strong, variable, and emission-line dominated spectrum, make spectroscopic analysis challenging. Hence, robust binary…
Given that mergers are often invoked to explain many exotic phenomena in massive star evolution, understanding the evolutionary phase directly preceding a merger, the overcontact phase, is of crucial importance. Despite its importance,…
Stellar systems composed of single, double, triple or high-order systems are rightfully regarded as the fundamental building blocks of the Milky Way. Binary stars play an important role in formation and evolution of the Galaxy. Through…
Various scenarios of contact binary evolution have been proposed in the past, giving hints of (sometimes contradictory) evolutionary sequence connecting A-type and W-type systems. As the components of close detached binaries approach each…
The overall frequency and other statistical properties of binary systems suggest that star formation is intrinsically a complex and chaotic process, and that most binaries and single stars actually originate from the decay of multiple…
Globular clusters were thought to be simple stellar populations, but recent photometric and spectroscopic evidence suggests that the clusters' early formation history was more complicated. In particular, clusters show star-to-star abundance…
In the present review we discuss the past and present status of the interacting OB-type binary frequency. We critically examine the popular idea that Be-stars and supergiant sgB[e] stars are binary evolutionary products. The effects of…
Massive stars rapidly change their masses through strong stellar winds and mass transfer in binary systems. We show that such mass changes leave characteristic signatures in stellar mass functions of young star clusters which can be used to…
The binary fraction in young open clusters exceeds that of field stars, making the study of binary dynamical evolution in clusters essential for understanding the origins and evolution of field binaries. Using N-body simulations based on…
Emission-line stars in young open clusters are identified to study their properties, as a function of age, spectral type and their evolutionary state. 207 open star clusters were observed using slitless spectroscopy method and 157 emission…
Be stars are rapidly rotating main-sequence (MS) stars that play a crucial role in understanding stellar evolution and binary interactions. In this letter, we propose a new formation scenario for black hole (BH) + Be star binaries…
We use N-body integration to follow the evolution of clusters of 200 binary systems with different initial half mass radii $R_{0.5}$. We also simulate single-star clusters. All clusters evolve according to the same $n(t)$ curve, where…
The total mass of distant star clusters is often derived from the virial theorem, using line-of-sight velocity dispersion measurements and half-light radii. Although most stars form in binary systems, this is mostly ignored when…
The formation and evolution of young star clusters and OB associations is fundamental to our understanding of the star formation process, the conditions faced by young binary and planetary systems, and the formation of long-lived open and…
Characterization of the binary fractions in star clusters is of fundamental importance for many fields in astrophysics. Observations indicate that the majority of stars are found in binary systems, while most stars with masses greater than…
The rapid circularization and synchronization of the stellar components in an eccentric binary system at the onset of Roche lobe overflow (RLO) is a fundamental assumption common to all binary stellar evolution and population synthesis…
In contrast to the field, the binaries in dense stellar systems are frequently not primordial, and could be either dynamically formed or significantly altered from their primordial states. Destruction and formation of binaries occur in…