Accurate Abundances in Some Giant Stars of the Globular Cluster ω Centauri

1988 ◽  
Vol 132 ◽  
pp. 537-540
Author(s):  
F. Spite ◽  
M. Spite ◽  
P. François
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Dwarf Galaxies ◽  
Magellanic Clouds ◽  
High Signal ◽  
Signal To Noise ◽  
Giant Stars ◽  
Great Complexity ◽  
Made In

The globular cluster ω Cen is known as a very peculiar cluster : some stars show anomalous abundances. Accurate abundance determinations of various elements have been made in six giants of ω Cen, using spectra with high signal to noise ratios. The results suggest some constraints on the origin of the anomalies, but also show the great complexity of the problem, which requires more observations for approaching a solution. A solution would help to understand the evolution of other objects : globular clusters in the Magellanic Clouds, and dwarf galaxies.

scholarly journals The Composition of Warm Giants in M 71 and M 5

1988 ◽  
Vol 126 ◽  
pp. 497-498
Author(s):  
Catherine A. Pilachowski ◽  
Christopher Sneden
Keyword(s):  
High Resolution ◽  
Globular Cluster ◽  
Globular Clusters ◽  
High Dispersion ◽  
High Signal ◽  
Signal To Noise

In 1979 a disturbing controversy arose in the field of globular cluster research when Cohen (1980) and Pilachowski, Canterna, and Wallerstein (1980) announced the results of the first high dispersion studies of the composition of giants in the globular clusters M 71 and 47 Tucanae. In contrast to earlier studies, which found metallicities of typically −0.3 and −0.5 dex, these investigators obtained values of −1.3 and −1.1. Since then, many have attempted to redetermine the abundances of M 71 and 47 Tuc to explain the discrepant results. These efforts have all suffered from the absence of high signal-to-noise, high resolution spectra of stars with temperatures above 4300 K.

scholarly journals The red globular-like clusters in the Magellanic Clouds

1964 ◽  
Vol 20 ◽  
pp. 354-357
Author(s):  
S. C. B. Gascoigne
Keyword(s):  
Chemical Composition ◽  
Globular Cluster ◽  
Spherical Symmetry ◽  
Globular Clusters ◽  
Progress Report ◽  
Magellanic Clouds ◽  
Systematic Observation ◽  
The Galaxy

There are about 50 clusters in the Magellanic Clouds which from their spherical symmetry, integrated colours, and luminosities appear similar to the globular clusters in the Galaxy. The colour-magnitude diagrams of these clusters should give moduli for the Clouds, indications of the age and chemical composition of the clusters themselves, and perhaps some information about the evolutionary tracks of old stars generally. The first investigation of this kind was carried out by Arp on the SMC clusters NGC 361 and 419. This was followed by papers by Eggen and Sandage and by the writer on NGC 1783 in the LMC, and by Tifft (1962) on NGC 121 in the SMC. Of these four clusters only NGC 121 appeared really similar to a galactic globular cluster, the others displaying features not reproduced by any known cluster in the Galaxy. Further work was clearly needed to clarify the problems raised by these results, and a program for the systematic observation of the colour-magnitude diagrams of red clusters in the Clouds was accordingly begun here in September 1961. This contribution is a progress report on this program.

scholarly journals X-Ray Binaries in Early Type Galaxies and the Globular Cluster Connection

2004 ◽  
Vol 194 ◽  
pp. 73-74
Author(s):  
T. J. Maccarone ◽  
A Kundu ◽  
S. E. Zepf ◽  
T. H. Puzia
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Early Type ◽  
X Ray ◽  
X Ray Binaries ◽  
Cluster Age ◽  
Made In

AbstractWe summarize the key observations made in recent observations of X-ray sources in early-type galaxies. Typically about half of the X-ray binaries in early-type galaxies are in globular clusters, they are preferentially found in metal rich globular clusters, and there is no indication that cluster-age is an important parameter. Theoretical challenges are presented by these results.

scholarly journals Short Period Variables in the Magellanic Cloud Cluster NGC 1466

1973 ◽  
Vol 21 ◽  
pp. 113-119 ◽  
Author(s):  
M. V. Norris
Keyword(s):  
Globular Cluster ◽  
Metal Content ◽  
Globular Clusters ◽  
Magellanic Clouds ◽  
Horizontal Branch ◽  
A Value ◽  
Short Period ◽  
Magnitude Diagram ◽  
The Galaxy ◽  
Metal Abundance

NGC 1466 (α1950 = 3h44.m6, δ1950= -71°45’) is a globular cluster which appears to be situated between the two Magellanic Clouds. Previous estimates (Gascoigne, 1966) put it at roughly the same distance from us as the LMC, so it is regarded as a member of the Cloud system. It is globular in appearance, and its colour-magnitude diagram confirms this classification. It has a fairly well-developed horizontal branch, and was found by Wesselink (1970) to be quite rich in variables. The metallicity index, Q, (van den Bergh, 1967) has a value of -0.36 for NGC 1466 (Andrews and Lloyd Evans, 1971). This would rank it with M5 and NGC 6171 as a cluster of intermediate metal content. This comparison is consistent with the value of Δ V for the cluster, which, at 2.m6, is representative of the Δ V values of globular clusters of intermediate metal abundance in the Galaxy.

scholarly journals Evolution of S stars in the magellanic clouds

1984 ◽  
Vol 105 ◽  
pp. 203-204
Author(s):  
T. Lloyd Evans
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Magellanic Clouds

Early S stars occur between M and C stars in the colour magnitude diagrams of intermediate age globular clusters in the Magellanic Clouds. Most have −4.2 ≥ Mbol ≥ −4.8 and are probably brighter in younger or more metal rich clusters. The galactic globular cluster NGC 6723 contains two marginal S stars at Mbol ∼ −3.3. The rare CS stars have Mbol ∼ −6, with no faint examples.

scholarly journals Globular Cluster Systems in the Hydra I Galaxy Cluster

2002 ◽  
Vol 207 ◽  
pp. 281-286
Author(s):  
Michael Hilker
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Dwarf Galaxies ◽  
Star Clusters ◽  
Galaxy Cluster ◽  
Cluster Center ◽  
Early Type ◽  
Cluster Systems ◽  
First Results ◽  
Globular Cluster System

In this contribution, first results of deep VLT (V,I) photometry in the central region of the Hydra I galaxy cluster are presented. Many star clusters have been identified not only around several early-type galaxies, but also in the intra-cluster field, as far as 250 kpc from the cluster center. Outside the bulges of the central galaxies NGC 3311 and NGC 3309, the intra-cluster globular cluster system is dominated by blue clusters whose spatial distribution is similar to that of the (newly discovered) dwarf galaxies in Hydra I. The color distributions of globular clusters around NGC 3311 and NGC 3309 are multimodal, with a sharp blue peak and a slightly broader distribution of the red cluster population.

scholarly journals MEASUREMENT OF THE RADIUS OF NEUTRON STARS WITH HIGH SIGNAL-TO-NOISE QUIESCENT LOW-MASS X-RAY BINARIES IN GLOBULAR CLUSTERS

2013 ◽  
Vol 772 (1) ◽  
pp. 7 ◽  
Author(s):  
Sebastien Guillot ◽  
Mathieu Servillat ◽  
Natalie A. Webb ◽  
Robert E. Rutledge
Keyword(s):  
Neutron Stars ◽  
Globular Clusters ◽  
High Signal ◽  
Signal To Noise ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries
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