منابع مشابه
Abundances in giant stars of the globular cluster NGC 6752 ⋆
Recent theoretical yields and chemical evolution models demonstrate that intermediate-mass AGB stars cannot reproduce the observed abundance distributions of O, Na, Mg, and Al. As a further observational test of this finding, we present elemental abundance ratios [X/Fe] for 20 elements in 38 bright giants of the globular cluster NGC 6752 based on high-resolution, high signal-to-noise spectra ob...
متن کاملLi in NGC 6752 and the formation of globular clusters ⋆
Li abundances for 9 Turnoff (TO) stars of the intermediate metallicity cluster ([Fe/H]=–1.4) NGC6752 are presented. The cluster is known to show abundance anomalies and anticorrelations observed in both evolved and main sequence stars. We find that Li abundance anticorrelates with Na (and N) and correlates with O in these Turn-Off stars. For the first time we observe Pop II hot dwarfs systemati...
متن کاملBeryllium abundance in turn-off stars of NGC 6752
Aims. To measure the beryllium abundance in two TO stars of the Globular Cluster NGC 6752, one oxygen rich and sodium poor, the other presumably oxygen poor and sodium rich. Be abundances in these stars are used to put on firmer grounds the hypothesis of Be as cosmochronometer and to investigate the formation of Globular Clusters. Methods. We present near UV spectra with resolution R∼ 45000 obt...
متن کاملThe peculiar millisecond pulsars in the globular clusters NGC 6397 and NGC 6752
The millisecond pulsars discovered in globular clusters are diagnostic tools for studying the dynamics of the clusters, the intracluster ionized gas and the evolution of the binaries embedded in the cluster. In the first two years of a search at 1.4 GHz in progress at the Parkes radio telescope 12 new millisecond pulsars have been discovered in 6 globular clusters in which no pulsars were previ...
متن کاملAbundances of C , N , O in slightly evolved stars in the globular clusters NGC 6397 , NGC 6752 and 47 Tuc ⋆
Abundances of C and N are derived from features due to the CH G-band and to the UV CN band measured on high resolution (R ∼ > 40, 000) UVES spectra of more than 40 dwarfs and subgiants in NGC 6397, NGC 6752 and 47 Tuc. Oxygen abundances (or upper limits) are available for all stars in the sample. Isotopic ratios 12 C/ 13 C were derived from the CH molecular band. This is the first determination...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1984
ISSN: 0074-1809
DOI: 10.1017/s0074180900030771