相关论文: Blue straggler stars in Globular Clusters: chemica…

We present the first dynamical study of Blue Straggler Stars (BSSs) in three Galactic globular clusters, NGC\,3201, NGC\,5139 ($\omega$Cen), and NGC\,6218, based on medium-resolution spectroscopy (R 10000) obtained with IMACS. Our BSS…

Blue straggler stars are unique main-sequence stars that appear more luminous, hotter, and therefore younger, than their coeval counterparts. In star clusters, these stars are located above the cluster turn-off in the Hertzsprung-Russell…

Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history. 'Blue stragglers' are stars massive enough that they should have evolved into white dwarfs long ago. Two possible…

Blue lurkers (BLs) are rejuvenated main-sequence stars hidden among normal main-sequence stars on color-magnitude diagrams of star clusters. In comparison, the blue straggler stars, formed via similar mass transfers or mergers, occupy a…

Blue stragglers are natural phenomena in star clusters. They originate through mass transfer in isolated binaries, as well as through encounters between two or more stars, in a complex interplay between stellar dynamics and stellar…

This chapter presents an overview of the main observational results obtained to date about Blue Straggler Stars (BSSs) in Galactic Globular Clusters (GCs). The BSS specific frequency, radial distribution, chemical composition and rotational…

We have used high resolution spectra obtained with the spectrograph FLAMES at the ESO Very Large Telescope to determine the kinematical properties and the abundance patterns of 20 blue straggler stars (BSSs) in the globular cluster M4. We…

Blue stragglers are anomalously luminous core hydrogen-burning stars formed through mass-transfer in binary/triple systems and stellar collisions. Their physical and evolutionary properties are largely unknown and unconstrained. Here we…

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…

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…

Blue Stragglers are stars located in an unexpected region of the color-magnitude diagram of a stellar population, as they appear bluer and more luminous than the stars in the turnoff region. They are ubiquitous, since they have been found…

Blue stragglers in globular clusters are abnormally massive stars that should have evolved off the stellar main sequence long ago. There are two known processes that can create these objects: direct stellar collisions and binary evolution.…

The discovery of a large population of intra-cluster star clusters in the central region of the Hydra I and Centaurus galaxy clusters is presented. Based on deep VLT photometry (V,I), many star clusters have been identified not only around…

By using high-resolution spectra acquired with FLAMES-GIRAFFE at the ESO/VLT, we measured radial and rotational velocities for 110 Blue Straggler stars (BSSs) in Omega Centauri, the globular cluster-like stellar system harboring the largest…

By using the high resolution spectrograph FLAMES@VLT we performed the first systematic campaign devoted to measure chemical abundances of blue straggler stars (BSSs). These stars, whose existence is not predicted by the canonical stellar…

We report the discovery of a variable blue straggler in the core of the globular cluster M5, based on a 12-hour long series of images obtained with the Planetary Camera aboard the Hubble Space Telescope. In addition, we present the light…

We conducted a spectroscopic study of 39 blue straggler stars in the globular cluster NGC 3201. The spectra of these stars were collected from the literature. We determined the radial velocity, atmospheric parameters (Teff, log g), and the…

In this paper we report on the most significant results from a statistical analysis of the main properties of globular cluster blue straggler stars (BSS) extracted from the HST snapshot database of photometrically homogeneous CMDs (Piotto…

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…

The formation of blue stragglers is still not completely understood, particularly the relationship between formation environment and mechanism. We use a large, homogeneous sample of blue stragglers in the cores of 57 globular clusters to…