Related papers: Blue straggler stars
In about 40% of the Local Group galaxies star clusters have been detected so far, but the census is still incomplete. The properties of these clusters are briefly reviewed, and the impact of galaxy environment on the evolution and survival…
A primary production mechanism for blue stragglers in globular clusters is thought to be collisionally-induced mergers, perhaps mediated by dynamical encounters involving binary stars. We model the formation and evolution of such blue…
The duration of starbursts is important for determining how they are regulated and the impact they have on their environment. Starbursts contain numerous prominent star clusters which typically comprise in total ~20% of the ultraviolet…
Binary systems can evolve into immensely different exotic systems such as blue straggle stars (BSSs), yellow straggler stars, cataclysmic variables, type Ia supernovae depending on their initial mass, the orbital parameters and evolution.…
Using the high-resolution observations obtained by the Hubble Space Telescope, we analyzed the blue straggler stars (BSSs) in the Large Magellanic Cloud cluster NGC 2213. We found that the radial distribution of BSSs is consistent with that…
Globular clusters (GCs) are among the oldest and most luminous stellar systems in the Universe, offering unique insights into galaxy formation and evolution. While the physical processes behind their origin have long remained elusive, major…
Collisions of main sequence stars occur frequently in dense star clusters. In open and globular clusters, these collisions produce merger remnants that may be observed as blue stragglers. Detailed theoretical models of this process require…
To probe the nature of stellar evolution in dense environments, we study the dense core of the globular cluster Messier 13 using pre-refurbishment Planetary Camera-I images obtained with the Hubble Space Telescope. We find 15 blue straggler…
Blue hook (BHk) stars are a rare class of horizontal branch stars that so far have been found in only very few Galactic globular clusters (GCs). The dominant mechanism for producing these objects is currently still unclear. In order to test…
Globular clusters are large and dense agglomerate of stars. At variance with smaller clusters of stars, they exhibit signs of some chemical evolution. At least for this reason, they are intermediate between open clusters and massive objects…
The core of the Galactic Globular Cluster M3 (NGC 5272) has been observed with the WFPC2 through the filters F255W, F336W, F555W, and F814W. Using these observations along with a thorough reanalysis of earlier catalogs, we have produced a…
OB associations are unbound groups of young stars made prominent by their bright OB members, and have long been thought to be the expanded remnants of dense star clusters. They have been important in astrophysics for over a century thanks…
The nature of the starburst phenomenon in galaxies is investigated using a narrow band color system designed to study color evolution in distant clusters. Work on zero redshift, luminous far-IR galaxies, calibrated by starburst models,…
Star clusters are ideal tracers of star formation activity in systems outside the volume that can be studied using individual, resolved stars. These unresolved clusters span orders of magnitude in brightness and mass, and their formation is…
The centers of most galaxies in the local universe are occupied by compact, barely resolved sources. Based on their structural properties, position in the fundamental plane, and integrated spectra, these sources clearly have a stellar…
We present a study of the properties of the star-cluster systems around pseudo-bulges of late-type spiral galaxies using a sample of 11 galaxies with distances from 17 to 37 Mpc. Star clusters are identified from multiband HST ACS and WFPC2…
Sub-subgiant stars (SSGs) lie to the red of the main-sequence and fainter than the red giant branch in cluster color-magnitude diagrams (CMDs), a region not easily populated by standard stellar evolution pathways. While there has been…
We have discovered new extended star clusters (ESCs) in a nearby dIrr galaxy NGC 6822. These clusters are the nearest sample of ESCs available to date. The key characteristic of ESCs is their large size compared to typical globular clusters…
The nature of pulsar-like compact stars is still in controversy although the first pulsar was found more than 40 years ago. Generally speaking, conventional neutron stars and non-mainstream quark stars are two types of models to describe…
The field of the globular cluster M12 (NGC 6218) was monitored between 1995 and 2009 in a search for variable stars. $BV$ light curves were obtained for 36 periodic or likely periodic variables. Thirty-four of these are new detections.…