Related papers: R144 : a very massive binary likely ejected from R…
Anticipating the kinematic constraints from the Gaia mission, we perform an extensive numerical study of the evolution of massive binary systems to predict the peculiar velocities that stars obtain when their companion collapses and…
Runaway stars are ejected from their place of birth in the Galactic disk, with some young B-type runaways found several tens of kiloparsecs from the plane traveling at speeds beyond the escape velocity. Young open clusters are a likely…
Abundance anomalies observed in globular cluster stars indicate pollution with material processed by hydrogen burning. Two main sources have been suggested: asymptotic giant branch (AGB) stars and massive stars rotating near the break-up…
Between 1996 and 2003 we have obtained 226 high resolution spectra of 16 stars in the field of the young open cluster NGC 6913, to the aim of constraining its main properties and study its internal kinematics. Twelve of the program stars…
Despite the discovery of thousands of exoplanets in recent years, the number of known exoplanets in star clusters remains tiny. This may be a consequence of close stellar encounters perturbing the dynamical evolution of planetary systems in…
This paper explores the stability of an Earth-like planet orbiting a solar mass star in the presence of an outer-lying intermediate mass companion. The overall goal is to estimate the fraction of binary systems that allow Earth-like planets…
We report the identification of a numerous binary star population in the recently discovered ~3 Gyr old open cluster UBC 274. It becomes visible once the cluster color-magnitude diagram is corrected by differential reddening and spans mass…
We derive the proper motions, membership probabilities, and velocity dispersions of stars in the regions of the young (about 2-4 Myr-old) open clusters NGC 2244 (the central cluster in the Monoceros R2 association) and NGC 6530 (the…
If binaries consisting of two 100 Msun black holes exist they would serve as extraordinarily powerful gravitational-wave sources, detectable to redshifts of z=2 with the advanced LIGO/Virgo ground-based detectors. Large uncertainties about…
Exoplanetary systems are found not only among single stars, but also binaries of widely varying parameters. Binaries with separations of 100--1000 au are prevalent in the Solar neighborhood; at these separations planet formation around a…
We present new, NTT longslit spectroscopy of the B[e] supergiant in the binary system R4 in the Small Magellanic Cloud. The data show extended, forbidden N and S emissions which are typical signatures of circumstellar matter. Their…
Performing N-body simulations, we examine the dynamics of BH-BH (10 Msun each) and NS-NS (1.4 Msun each) binaries formed in a cluster and its implications for gravitational wave detection. A significant fraction of compact binaries are…
A previous spectroscopic study identified the very massive O2 III star VFTS 16 in the Tarantula Nebula as a runaway star based on its peculiar line-of-sight velocity. We use the Gaia DR2 catalog to measure the relative proper motion of VFTS…
We report the results of a spectroscopic and polarimetric study of the massive, hydrogen-rich WN6h stars R144 (HD 38282 = BAT99-118 = Brey 89) and R145 (HDE 269928 = BAT99-119 = Brey 90) in the LMC. Both stars have been suspected to be…
We discuss the observations and theory of star cluster formation to argue that clusters form dynamically cool (subvirial) and with substructure. We then perform an ensemble of simulations of cool, clumpy (fractal) clusters and show that…
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…
We present the first multi-epoch radial velocity study of embedded young massive stars using near-infrared spectra obtained with ISAAC mounted at the ESO Very Large Telescope, with the aim to detect massive binaries. Our 16 targets are…
The discovery of planetary systems beyond our solar system has challenged established theories of planetary formation. Planetary orbits display a variety of unexpected architectures, and free-floating planets appear ubiquitous. The recent…
We study the dynamical interaction in which the two single runaway stars AE Aurigae and mu Columbae and the binary iota Orionis acquired their unusually high space velocity. The two single runaways move in almost opposite directions with a…
We analyze light and velocity curves of the eclipsing blue straggler V60 in the field of the globular cluster M55. We derive Mp=1.259+-0.025 Msun, Rp=1.102+-0.021 Rsun, Mbol,p=3.03+-0.09 mag for the primary and Ms=0.327+-0.017 Msun,…