Related papers: Blue Straggler Formation in Clusters
The overall frequency and other statistical properties of binary systems suggest that star formation is intrinsically a complex and chaotic process, and that most binaries and single stars actually originate from the decay of multiple…
We present preliminary results obtained from the comparison of the specific frequencies of Blue Straggler Stars (BSS) detected so far in a sample of 26 Galactic globular clusters. The number of BSS seems to increase almost linearly with…
Star formation is a fundamental process for galactic evolution. One issue over the last several decades has been determining whether star formation is induced by external triggers or is self-regulated in a closed system. The role of an…
In the present-day universe, it appears that most, and perhaps all, massive stars are born in star clusters. It also appears that all star clusters contain stars drawn from an approximately universal initial mass function, so that almost…
Blue straggler stars are the most prominent bright objects in the colour-magnitude diagram of a star cluster that challenges the theory of stellar evolution. Star clusters are the closest counterparts of the theoretical concept of simple…
Blue straggler stars in stellar clusters are a subset of stars that are bluer and appear younger than other cluster members, seemingly straggling behind in their evolution. They offer a unique opportunity to understand the stellar dynamics…
In this review, I present the case for how massive stars may form through stellar collisions. This mechanism requires very high stellar densities, up to 4 orders of magnitude higher than are observed in the cores of dense young clusters. In…
Though it is generally assumed that massive molecular clouds are the progenitors of globular clusters, their detailed formation mechanism is still unclear. Standard scenarios based on the collapse of a smooth matter distribution suffer from…
Many, possibly most, stars form in binary and higher-order multiple systems. Therefore, the properties and frequency of binary systems provide strong clues to the star-formation process, and constraints on star-formation models. However,…
We examine the blue straggler populations of 13 low-luminosity (M_V_t >~ -6) globular clusters and 2 old open clusters. These clusters test blue straggler formation in environments intermediate between higher luminosity (and usually higher…
Recent progress in the understanding of star formation is summarized. A consistent picture is emerging where molecular clouds form with turbulent velocity fields and clumpy substructure, imprinted already during their formation. The clouds…
Blue Straggler stars are present in all the properly observed Globular Clusters. They mimic a rejuvenated stellar population and their existence has been a puzzle for many years. We performed an extensive spectroscopic survey of the surface…
Nuclear Star Clusters are observed at the center of many galaxies. In particular in the center of the Milky Way the Nuclear Star Cluster coexists with a cen- tral supermassive black hole. The origin of these clusters is still unknown; a…
We continue our exploration of collisionally merged stars in the blue straggler region of the color-magnitude diagram. We report the results of new SPH calculations of parabolic collisions between two main-sequence stars, with the initial…
Nuclear star clusters are among the densest stellar systems known and are common in both early- and late-type galaxies. They exhibit scaling relations with their host galaxy which may be related to those of supermassive black holes. These…
We summarize current models of the formation of spheroidal stellar systems. Whereas globular clusters form in an efficient mode of star formation inside turbulent molecular clouds, the origin of galactic spheroids, that is bulges, dwarf…
This review concentrates almost entirely on globular star clusters. It emphasises the increasing realisation that few of the traditional problems of star cluster astronomy can be studied in isolation: the influence of the Galaxy affects…
Recent high-quality Hubble Space Telescope (HST) photometry shows that the main sequences (MS) stars of young star clusters form two discrete components in the color-magnitude diagram (CMD). Based on their distribution in the CMD, we show…
Stars in star clusters are thought to form in a single burst from a common progenitor cloud of molecular gas. However, massive, old globular clusters -- with ages greater than 10 billion years and masses of several hundred thousand solar…
Blue straggler stars (BSSs) are brighter and bluer than the main-sequence (MS) turnoff and more massive than MS stars.Two scenarios for their formation have been proposed: collision-induced stellar mergers (COL-BSSs),or mass-transfer in…