Related papers: Double or binary: on the multiplicity of open star…
I present the latest results from our group about the multiple stellar populations in the old Milky Way globular clusters (GCs) and in the young systems both in the Magellanic Clouds and in the Milky Way. For the ancient GCs in our Galaxy I…
The formation of massive stars is one of the major unsolved problems in stellar astrophysics. However, only few if any of these are found as single stars, on average massive stars have more than one companion. Many of them are born in dense…
The predicted rate of binary black hole mergers from galactic fields can vary over several orders of magnitude and is extremely sensitive to the assumptions of stellar evolution. But in dense stellar environments such as globular clusters,…
A number of scenarios for the formation of multiple populations in globular clusters (GCs) predict that second generation (2G) stars form in a compact and dense subsystem embedded in a more extended first-generation (1G) system. If these…
In this work, a sample of planetary nebulae located in the inner-disk and bulge of the Galaxy is used in order to find the galactocentric distance which better separates these two populations, from the point of view of abundances.…
Wide or fragile pairs are sensitive probes of the galactic potential, and they have been used to provide information about the galactic tidal field, the density of GMC and the masses of dark matter perturbers present in both the disk and…
The X-ray binary population of the Small Magellanic Cloud (SMC) contains a large number of massive X-ray binaries and the recent survey of the SMC by XMM-Newton has resulted in almost 50 more tentative high mass X-ray binary candidates.…
The Small Magellanic Cloud (SMC) has recently been found to harbour more than two hundred per cent increase of its known cluster population. We provide here with solid evidence that such an unprecedented number of clusters could be largely…
The Galactic bulge is a tumultuous dense region of space, packed with stars separated by far smaller distances than those in the Solar neighborhood. A quantification of the frequency and proximity of close stellar encounters in this…
The currently known Galactic globular cluster population extends out to a maximum galactocentric distance of $\sim$ 145 kpc, with the peculiarity that the outermost clusters predominantly have an inward velocity. Orbit averaging finds that…
In this paper we study the evolution of a primordial black hole binary (BHB) in a sample of over 1500 direct-summation $N-$body simulations of small-and intermediate-size isolated star clusters as proxies of galactic open clusters. The BHBs…
Close to 70 radio pulsars have now been discovered in 23 globular clusters, with a record 22 pulsars observed in 47 Tuc alone. Accurate timing solutions, including positions in the cluster, are known for many of the pulsars. These recent…
Most of massive stars form in binary or higher-order systems in clumpy, sub-structured clusters. In the very first phases of their life, these stars are expected to interact with the surrounding environment, before being released to the…
In order to understand the Galactic structure, we perform a statistical analysis of the distribution of various cluster parameters based on an almost complete sample of Galactic open clusters yet available. The geometrical and physical…
The population of young stars near the Supermassive black hole (SMBH) in the Galactic Center (GC) has presented an unexpected challenge to theories of star formation. Kinematics measurements of these stars have revealed a stellar disk…
The blue supergiant (BSG) domain contains a large variety of stars whose past and future evolutionary paths are still highly uncertain. Since binary interaction plays a crucial role in the fate of massive stars, investigating the…
Binary stars are present in all stellar systems, yet their role is far from being fully understood. We investigate the effect of unresolved binaries in the derivation of open clusters' mass by star counts. We start from the luminosity…
A significant fraction of, and possibly all, stars form in binary or multiple systems. For Solar-mass stars in the Galactic field, the distribution of orbital separations is log-normal over seven orders of magnitude, from $10^{-2} - 10^5$…
We present constraints on the variability and binarity of young stars in the central 10 arcseconds (~0.4 pc) of the Milky Way Galactic Center (GC) using Keck Adaptive Optics data over a 12 year baseline. Given our experiment's photometric…
Most main sequence stars, unlike our Sun, belong to multiple systems with two or more stars. How and when these multiples come together and become bound is uncertain, since the earliest stages of star formation are difficult to resolve. We…