Related papers: Encounters in the ONC - observing imprints of star…
Centers of galaxies host both a supermassive black hole and a dense stellar cluster. Such an environment should lead to stellar collisions, possibly at very high velocities so that the total energy involved is of the same order as…
In the last decade star clusters have been found in the centers of spiral galaxies across all Hubble types. We here present a spectroscopic study of the exceptionally bright (10^6 - 10^8 Lsun) but compact (Re ~ 5 pc) nuclear star clusters…
We examine the effect of an accretion disc on the orbits of stars in the central star cluster surrounding a central massive black hole by performing a suite of 39 high-accuracy direct N-body simulations using state-of-the art software and…
FU Orionis type objects (fuors) are characterized by rapid (tens to hundreds years) episodic outbursts, during which the luminosity increases by orders of magnitude. One of the possible causes of such events is a close encounter between…
[Abridged] We imaged a 2' x 2' region of the Orion Nebula cluster in 1.3 mm wavelength continuum emission with the recently commissioned Combined Array for Research in Millimeter Astronomy (CARMA) and with the Submillimeter Array (SMA). Our…
Observations of structure in circumstellar debris discs provide circumstantial evidence for the presence of massive planets at large (several tens of au) orbital radii, where the timescale for planet formation via core accretion is…
The dipper is a novel class of young stellar object associated with large drops in flux on the order of 10 to 50 per cent lasting for hours to days. Too significant to arise from intrinsic stellar variability, these flux drops are currently…
Context: the observations of the proplyds in the Orion Nebula Cluster, showing clear evidence of ongoing photoevaporation, have provided a clear proof about the role of the externally induced photoevaporation in the evolution of…
Nuclear star clusters (NCs) are found to exist in the centres of many galaxies and appear to follow scaling relations similar to those of super-massive black holes. Previous analytical work has suggested that such relations are a…
Debris discs are commonly detected orbiting main-sequence stars, yet little is known regarding their fate as the star evolves to become a giant. Recent observations of radial velocity detected planets orbiting giant stars highlight this…
We present results from a near-infrared (NIR) adaptive optics (AO) survey of pre-main-sequence stars in the Lupus Molecular Cloud with VLT/NACO to identify (sub)stellar companions down to $\sim$20 au separation and investigate the effects…
Young solar-type stars are known to be strong X-ray emitters and their X-ray spectra have been widely studied. X-rays from the central star may play a crucial role in the thermodynamics and chemistry of the circumstellar material as well as…
We study the occurrence of physical collisions between stars in young and compact star cluster. The calculations are performed on the GRAPE-4 with the starlab software environment which include the dynamical evolution and the nuclear…
The structure of planetary systems around their host stars depends on their initial formation conditions. Massive planets will likely be formed as a consequence of rapid migration of planetesimals and low mass cores into specific trapping…
We present the results of a binary population study in the Orion Nebula Cluster (ONC) using archival Hubble Space Telescope (HST) data obtained with the Advanced Camera for Surveys (ACS) in Johnson V filter (HST Proposal 10246, PI M.…
Debris disks are the dust disks found around ~20% of nearby main sequence stars in far-IR surveys. They can be considered as descendants of protoplanetary disks or components of planetary systems, providing valuable information on…
We investigate the structure of our Galaxy's young stellar disc by fitting the distribution functions (DFs) of a new family to five-dimensional Gaia data for a sample of $47\,000$ OB stars. Tests of the fitting procedure show that the young…
(abridged) The old Star Cluster (SC) systems surrounding any sofar investigated galaxy represent a powerful tool for the understanding of the cosmological evolution of their host galaxies. Phases of enhanced cluster formation can be…
In recent years, it has been demonstrated that massive stars see their infant circumstellar medium shaped into a large, irradiated, gravitationally unstable accretion disc during their early formation phase. Such discs constitute the gas…
Numerical simulations of the dynamical friction suffered by a star cluster near the Galactic center have been performed with a parallelized tree code. Gerhard (2001) has suggested that dynamical friction, which causes a cluster to lose…