Related papers: Are there brown dwarfs in globular clusters?
Under the right conditions brown dwarfs that gain enough mass late in their lives to cross the hydrogen burning limit will not turn into low-mass stars, but rather remain essentially brown dwarf-like. While these objects, called either…
The multitude of binary black hole coalescence detections in gravitational waves has renewed our interest on environments that can be the cradle of these mergers. In this work we study merger rates of binary black holes in globular clusters…
Star clusters can be found in galaxy mergers, not only in central regions, but also in the tidal debris. In both the Eastern and Western tidal tails of NGC 3256 there are dozens of young star clusters, confirmed by their blue colors and…
(abridged) Observations of very high speeds among pulsars in the Galactic disk present a puzzle regarding neutron stars in globular clusters. The inferred characteristic speed of single pulsars in the Galaxy is $\sim 5-10$ times as large as…
Highly eccentric binary systems appear in many astrophysical contexts, ranging from tidal capture in dense star clusters, precursors of stellar disruption by massive black holes, to high-eccentricity migration of giant planets. In a highly…
We have investigated i) the formation of gravitationally bounded pairs of gas-giant planets (which we call "binary planets") from capturing each other through planet-planet dynamical tide during their close encounters and ii) the following…
We study the evolution of first star (Population III) binaries. Under specific conditions, these stars may produce high redshift gamma-ray bursts (GRBs). We demonstrate that the occurrence rate of GRBs does not depend sensitively on…
Galaxy clusters contain a large population of low mass dwarf elliptical galaxies whose exact origin is unclear: their colors, structural properties and kinematics differ substantially from those of dwarf irregulars in the field. We use the…
Abridged/ We present numerical results on the properties of young binary and multiple stellar systems. Our analysis is based on a series of SPH + Nbody simulations of the fragmentation of small molecular clouds, that fully resolve the…
We perform a suite of numerical simulations of tidal disruption events, using smoothed particle hydrodynamics, for a close binary system consisting of two low-mass white dwarfs, and an intermediate mass non-spinning black hole. The binary…
In studying encounters between binaries and single stars, one is interested in three classes of events: exchanges of stars, hardening of the original binary by a third star, and the production of merged objects. We present a means for…
We analyse color-magnitude diagrams of eight Globular Clusters (GCs) in the outer Galactic Halo. Images were taken with the Wide Field Channel of the Advanced Camera for Survey and the Ultraviolet and Visual Channel of the Wide Field Camera…
In a dense stellar environment, such as the core of a globular cluster (GC), dynamical interactions with black holes (BHs) are expected to lead to a variety of astrophysical transients. Here we explore tidal disruption events (TDEs) of…
Globular clusters (GCs) are found in all types of galaxies and harbor some of the most extreme stellar systems, including black holes that may dynamically assemble into merging binaries (BBHs). Uncertain GC properties, including when they…
Compact binary mergers forming in star clusters may exhibit distinctive features that can be used to identify them among observed gravitational-wave (GW) sources. Such features likely depend on the host cluster structure and the physics of…
Over half of all observed hot subdwarf B (sdB) stars are found in binaries, and over half of these are found in close configurations with orbital periods of 10$ \,\rm{d}$ or less. In order to estimate the companion masses in these…
We present radial velocity observations of four extremely low-mass (0.2 Msol) white dwarfs. All four stars show peak-to-peak radial velocity variations of 540 - 710 km/s with 1.0 - 5.9 hr periods. The optical photometry rules out…
Hundreds of brown dwarfs (BDs) have been discovered in the last few years in stellar clusters and among field stars. BDs are almost as numerous as hydrogen burning stars and so a theory of star formation should also explain their origin.…
The existence of supermassive black holes lurking in the centers of galaxies and of stellar binary systems containing a black hole with a few solar masses has been established beyond reasonable doubt. The idea that black holes of…
Planetary material accreted by white dwarfs provides unique insights regarding exoplanetary composition. The evolutionary pathways of planetary bodies around white dwarfs are crucial to understanding the presence of close-in planetary…