Related papers: Runaway and Hypervelocity Stars from Compact Objec…
Hypervelocity stars are believed to be ejected out from the Galactic center through dynamical interactions of (binary) stars with the central massive black hole(s). In this letter, we report 13 metal-poor F-type hypervelocity star…
Globular clusters (GCs) are sites of extremely efficient star formation, and recent studies suggest they significantly contributed to the early Milky Way's stellar mass build-up. Although their role has since diminished, GCs' impact on the…
Globular clusters (GCs) are known to host multiple stellar populations showing chemical anomalies in the content of light elements. The origin of such anomalies observed in Galactic GCs is still debated. Here we analyse data compiled from…
About 20% of all massive stars in the Milky Way have unusually high velocities, the origin of which has puzzled astronomers for half a century. We argue that these velocities originate from strong gravitational interactions between single…
In the present paper we combine an N-body code that simulates the dynamics of young dense stellar systems with a massive star evolution handler that accounts in a realistic way for the effects of stellar wind mass loss. We discuss two…
The disruption of a binary star system by the massive black hole at the Galactic Centre, SgrA*, can lead to the capture of one star around SgrA* and the ejection of its companion as a hypervelocity star (HVS). We consider the possibility…
A relevant fraction of massive stars are runaway stars. These stars move with a significant peculiar velocity with respect to their environment. We aim to discover and characterize the population of massive and early-type runaway stars in…
It is challenging to reliably identify stars that were born together outside of actively star-forming regions and bound stellar systems. However, co-natal stars should be present throughout the Galaxy, and their demographics can shed light…
Milli-arcsecond astrometry provided by Hipparcos and by radio observations makes it possible to retrace the orbits of some of the nearest runaway stars and pulsars to determine their site of origin. The orbits of the runaways AE Aurigae and…
We model the effects of collisions and close encounters on the stellar populations observed in the Milky Way nuclear stellar cluster (NSC). Our analysis is based on $N$-body simulations in which the NSC forms by accretion of massive stellar…
Globular clusters are gravitationally bound stellar systems containing on the order of 100,000 stars. Due to the high stellar densities in the cores of these clusters, close encounters and even physical collisions between stars are…
Both simulations and observations indicate that stars form in filamentary, hierarchically clustered associations, most of which disperse into their galactic field once feedback destroys their parent clouds. However, during their early…
Theory predicts that we should find fast, ejected (runaway) stars of all masses around dense, young star-forming regions. $N$-body simulations show that the number and distribution of these ejected stars could be used to constrain the…
We present the methods and preparatory work for our study of the collisional runaway scenario to form a very massive star (VMS, M > 400 Msun) at the centre of a young, compact stellar cluster. In the first phase of the process, a very dense…
We have carried out a large grid of N-body simulations in order to investigate if mass-loss as a result of primordial gas expulsion can be responsible for the large fraction of second generation stars in globular clusters (GCs) with…
The discovery of hypervelocity stars (HVS) leaving our galaxy with speeds of nearly $10^{3}$ km s$^{-1}$ has provided strong evidence towards the existence of a massive compact object at the galaxy's center. HVS ejected via the disruption…
Milli-arcsecond astrometry provided by Hipparcos and by radio observations makes it possible to retrace the orbits of nearby runaway stars and pulsars with sufficient accuracy to identify their parent stellar cluster or association. For two…
Some young, massive stars can be found in the Galactic halo. As star formation is unlikely to occur in the halo, they must have been formed in the disk and been ejected shortly afterwards. One explanation is a supernova in a tight binary…
The enormous velocities of the so called hypervelocity stars (HVSs) derive, likely, from close interactions with massive black holes, binary stars encounters or supernova explosions. In this paper, we investigate the origin of hypervelocity…
Massive stars can be efficiently ejected from their birth clusters through encounters with other massive stars. We study how the dynamical ejection fraction of O star systems varies with the masses of very young star clusters, Mecl, by…