Related papers: Towards Multiple-Star Population Synthesis
We consider the multiplicity of stellar systems with (combined) magnitude brighter than 6.00 in Hipparcos magnitudes. We identify 4559 such bright systems (including the Sun), and the frequencies of multiplicities 1, 2,..., 7 are found to…
We discuss the observed multiplicity of massive stars and implications on theories of massive star formation. After a short summary of the literature on massive star multiplicity, we focus on the O- and B-type stars in the Orion Nebula…
Stellar multiplicity is an ubiquitous outcome of the star formation process. Characterizing the frequency and main characteristics of multiple systems and their dependencies on primary mass and environment is therefore a powerful tool to…
Most stars - especially young stars - are observed to be in multiple systems. Dynamical evolution is unable to pair stars efficiently, which leads to the conclusion that star-forming cores must usually fragment into \geq 2 stars. However,…
Observational advances over the last decade have enabled high-resolution, interferometric studies of forming multiple systems, statistical surveys of multiplicity in star-forming regions, and new insights into disk evolution and planetary…
There is much debate on how high-mass star formation varies with environment, and whether the sparsest star-forming environments are capable of forming massive stars. To address this issue, we have observed eight apparently isolated OB…
We demonstrate that the mass of the most massive star in a cluster correlates non-trivially with the cluster mass. A simple algorithm according to which a cluster is filled up with stars that are chosen randomly from the standard IMF but…
We present the results of a comprehensive assessment of companions to solar-type stars. A sample of 454 stars, including the Sun, was selected from the Hipparcos catalog with {\pi} > 40 mas, {\sigma}_{\pi}/{\pi} < 0.05, 0.5 < B - V < 1.0 (~…
A complete periodic star extraction and classification scheme is set up and tested with the Hipparcos catalogue. The efficiency of each step is derived by comparing the results with prior knowledge coming from the catalogue or from the…
We use high-precision photometry of red-giant-branch (RGB) stars in 57 Galactic globular clusters (GCs), mostly from the `Hubble Space Telescope (HST) UV Legacy Survey of Galactic globular clusters', to identify and characterize their…
Galactic globular clusters are not simple stellar populations. And nothing is simple in their study, basically because we try to reconstruct chains of events that occurred at redshift z > 2-3 by observing these objects at z=0, after a…
We report about an ongoing photometric and spectroscopic monitoring survey of about 250 O- and 540 B-type stars in the southern Milky Way with the aim to determine the fraction of close binary systems as a function of mass and to determine…
Combining population synthesis models with simple Montecarlo simulations of stochastic effects in the number of stars occupying sparsely populated stellar evolutionary phases in the HRD, I show that the scatter observed in the photometric…
In this paper I combine the results of a set of population synthesis models with simple Montecarlo simulations of stochastic effects in the number of stars occupying sparsely populated stellar evolutionary phases, to show that the scatter…
A new stellar library developed for stellar population synthesis modeling is presented. The library consist of 985 stars spanning a large range in atmospheric parameters. The spectra were obtained at the 2.5m INT telescope and cover the…
The Kepler mission provides a wealth of multiple transiting planet systems (MTPS). The formation and evolution of multi-planet systems are likely to be influenced by companion stars given the abundance of multi stellar systems. We study the…
According to theoretical considerations, multiplicity of hierarchical stellar systems can reach, depending on masses and orbital parameters, several hundred, while observational data confirm existence of at most septuple (seven-component)…
Be stars are widely considered to be the product of binary interaction. However, whether all Be stars are formed via binary interaction is unclear, and detailed estimates of the multiplicity of Be stars and characterization of their…
The planet occurrence rate for multiple stars is important in two aspects. First, almost half of stellar systems in the solar neighborhood are multiple systems. Second, the comparison of the planet occurrence rate for multiple stars to that…
Massive stars (> 8 $M_\odot$) are known to have high degrees of multiplicity, e.g., with about 60% in triples or higher-order multiples. Such high levels of multiplicity may arise during formation (primary multiplicity) or through dynamical…