... The overall globular cluster population is divided by gap in the metallicity function at [Fe/H]=-1.0 into two discrete groups with well-defined maxima at [Fe/H]=-1.60?0.03 dex, and -0.60?0.04 dex. ... Clusters with extremely blue horizontal branches occupy a spherical volume of radius ~ 9 kpc, have high rotational velocities ( V rot =77?33 km/s), have substantial and equal negative radial and vertical metallicity gradients, and are, on average, the oldest group (the old-halo subsystem). ...

... Dept. for Physics of Stars&Galaxies . ... Investigation of physical characteristics and evolution of galaxies with active star formation, according to observations at telescopes in the world's largest X-ray, ultraviolet, visible, infrared and radio wavelengths of electromagnetic radiation. ... The analysis of stellar spectra considering deviations from LTE, the evolution and definition of the physical characteristics of stars of late spectral classes.. ... Stars . ... Star clusters of the Galaxy . ...

Stellar Clusters are very useful laboratories for empirically studying stellar evolution. ... All cluster stars are at the same distance . All cluster stars have the same physical age . ... CM diagram Young Cluster In this case we see the Main Sequence fully represented. The blue dots represent massive stars with short main sequence lifetimes. ... Thus, identifying the most massive star which is still on the main sequence is an effective means of determining the age of a stellar cluster. ...

... Programme . ... Abstract: Globular clusters can probe the formation history of galaxies by providing evidence for the chemical evolution and major episodes of star formation in their host galaxies, by examining their kinematic signatures, as well as their structural parameters. ... The giant elliptical NGC 5128 (Centaurus A), at a mere 4 Mpc away, gives us the only opportunity to study in extensive detail the globular cluster system of a recent merger galaxy. ...

Fundamental parameters and time evolution of mass loss are investigated for post-main-sequence stars in the Galactic globular cluster 47 Tucanae (NGC 104). ... We confirm the cluster's distance as d = 4611+213 -200 pc and age as 12 ТБ 1 Gyr. Horizontal branch models appear to confirm that no more red giant branch mass loss occurs in 47 Tuc than in the more metal-poor Я? Centauri, though difficulties arise due to inconsistencies between the models. ...

... Science . ... Science Users Information > Science Activities > Science in Garching > Research Area: STELLAR POPULATIONS . ... Research Area: STELLAR POPULATIONS . Subject in this research area aim at understanding the stellar content of nearby star clusters and galaxies with the goal of understanding their formation and evolution history. ... Evolution of Galaxies and the ISM Stellar Populations Faculty . ... Planets and Star Formation Stellar Populations Stellar Structure and Evolution Faculty . ...

... galaxies: bulges galaxies: clusters: general galaxies: clusters: individual: . ... star formation statistics stellar content structure Cosmology ( cosmology :) cosmic background radiation ( cosmology :) cosmological parameters cosmology : miscellaneous cosmology : observations cosmology : theory ( cosmology :) dark ages, reionization, first stars ( cosmology :) dark energy ( cosmology :) dark matter ( cosmology :) diffuse radiation ( cosmology :) distance scale ( cosmology :) early Universe (...

... 2000, ApJ, 537, L49 . ... F. Palla . Invited Talk at the IAU Symposium 200 "The formation of binary stars" eds. R.D. Mathieu and H. Zinnecker (ASP Conf. Ser.) in press . Optical follow-up of ROSAT discovered candidate members of the open cluster Coma Berenices . ... 2000, A , in press . ... 2000, ApJ, in press . ... 2000, ApJ, in press (Sept. ... 2000, ApJ Lett., in press . ... Click to examine publications from other years . ... Star Formation Group . ... Arcetri Home Page . ...