Depicting the Early Evolution of Globular Clusters Through the Lens of Multiple Stellar Populations

2014 ◽  
pp. 193-201
Author(s):  
Corinne Charbonnel
2019 ◽  
Vol 14 (S351) ◽  
pp. 524-527
Author(s):  
Maria A. Tiongco ◽  
Enrico Vesperini ◽  
Anna Lisa Varri

AbstractWe present several results of the study of the evolution of globular clusters’ internal kinematics, as driven by two-body relaxation and the interplay between internal angular momentum and the external Galactic tidal field. Via a large suite of N-body simulations, we explored the three-dimensional velocity space of tidally perturbed clusters, by characterizing their degree of velocity dispersion anisotropy and their rotational properties. These studies have shown that a cluster’s kinematical properties contain distinct imprints of the cluster’s initial structural properties, dynamical history, and tidal environment. Building on this fundamental understanding, we then studied the dynamics of multiple stellar populations in globular clusters, with attention to the largely unexplored role of angular momentum.


2009 ◽  
Vol 5 (S265) ◽  
pp. 344-345
Author(s):  
B. Barbuy ◽  
S. Ortolani ◽  
M. Zoccali ◽  
V. Hill ◽  
D. Minniti ◽  
...  

AbstractVery few abundance analyses of individual stars in metal-poor globular clusters in the galactic bulge are available. The main purpose of this study is to derive abundances in individual stars of such clusters, in order to establish their abundance pattern, trying to characterize the oldest bulge stellar populations.


2009 ◽  
Vol 5 (S262) ◽  
pp. 27-30
Author(s):  
Aldo A. R. Valcarce ◽  
Márcio Catelan

AbstractGlobular clusters (GCs) are spheroidal concentrations typically containing of the order of 105 to 106, predominantly old, stars. Historically, they have been considered as the closest counterparts of the idealized concept of “simple stellar populations.” However, some recent observations suggest than, at least in some GCs, some stars are present that have been formed with material processed by a previous generation of stars. In this sense, it has also been suggested that such material might be enriched in helium, and that blue horizontal branch stars in some GCs should accordingly be the natural progeny of such helium-enhanced stars. In this contribution we show that, at least in the case of M3 (NGC 5272), the suggested level of helium enrichment is not supported by the available, high-precision observations.


2016 ◽  
Vol 463 (4) ◽  
pp. 3768-3782 ◽  
Author(s):  
R. Wagner-Kaiser ◽  
D. C. Stenning ◽  
A. Sarajedini ◽  
T. von Hippel ◽  
D. A. van Dyk ◽  
...  

2015 ◽  
Vol 12 (S316) ◽  
pp. 328-333
Author(s):  
W. Chantereau ◽  
C. Charbonnel ◽  
G. Meynet

AbstractOur knowledge of the formation and early evolution of globular clusters (GCs) has been totally shaken with the discovery of the peculiar chemical properties of their long-lived host stars. Therefore, the interpretation of the observed Colour Magnitude Diagrams (CMD) and of the properties of the GC stellar populations requires the use of new stellar models computed with relevant chemical compositions. In this paper we use the grid of evolution models for low-mass stars computed by Chantereau et al. (2015) with the initial compositions of second-generation stars as predicted by the fast rotating massive stars scenario to build synthesis models of GCs. We discuss the implications of the assumed initial chemical distribution on 13 Gyr isochrones. We build population synthesis models to predict the fraction of stars born with various helium abundances in present day globular clusters (assuming an age of 13 Gyr). With the current assumptions, 61 % of stars on the main sequence are predicted to be born with a helium abundance in mass fraction, Yini, smaller than 0.3 and only 11 % have a Yini larger than 0.4. Along the horizontal branch, the fraction of stars with Yini inferior to 0.3 is similar to that obtained along the main sequence band (63 %), while the fraction of very He-enriched stars is significantly decreased (only 3 % with Yini larger than 0.38).


2016 ◽  
Vol 826 (1) ◽  
pp. 42 ◽  
Author(s):  
R. Wagner-Kaiser ◽  
D. C. Stenning ◽  
E. Robinson ◽  
T. von Hippel ◽  
A. Sarajedini ◽  
...  

Author(s):  
Boris Dirsch ◽  
Tom Richtler ◽  
Doug Geisler ◽  
J. C. Forte ◽  
L. P. Bassino ◽  
...  

2019 ◽  
Vol 14 (S351) ◽  
pp. 442-446
Author(s):  
Alessandra Mastrobuono-Battisti ◽  
Sergey Khoperskov ◽  
Paola Di Matteo ◽  
Misha Haywood

AbstractThe Galactic globular cluster system went and is still going through dynamical processes that require to be explored in detail. Here we illustrate how primordial massive globular clusters born in the Milky Way’s disc evolved by stripping material from each other or even merging very early during their lives. These processes might explain the puzzling presence of star-by-star spreads in iron content observed in massive globular clusters and should be taken into account when studying globular cluster stellar populations. In this context, we show how the direct comparison between the predictions provided by our direct N-body simulations and observations can shed light on the origin and chemo-dynamical evolution of globular clusters.


1996 ◽  
Vol 174 ◽  
pp. 19-28
Author(s):  
Puragra Guhathakurta ◽  
Brian Yanny ◽  
Donald P. Schneider ◽  
John N. Bahcall

We present results from an ongoing program to probe the dense central parts of Galactic globular clusters using multicolor Hubble Space Telescope images (WF/PC-I and WFPC2). Our sample includes the dense clusters M15, 47 Tuc, M30, NGC 6624, M3 and M13. The two main goals of our program are to measure the shape of stellar density profile in clusters (the slope of the density cusp in post core collapse clusters, in particular) and to understand the nature of evolved stellar populations in very dense regions and their variation as a function of radius. The latter includes studies of blue straggler stars and of the central depletion of bright red giants. Our recent WFPC2 study of M15 is described in detail.


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