The horizontal-branch stars in globular clusters. I - The period-shift effect, the luminosity of the horizontal branch, and the age-metallicity relation

1990 ◽  
Vol 350 ◽  
pp. 155 ◽  
Author(s):  
Young-Wook Lee ◽  
Pierre Demarque ◽  
Robert Zinn
Keyword(s):  
Globular Clusters ◽  
Horizontal Branch ◽  
Horizontal Branch Stars ◽  
Period Shift ◽  
Shift Effect

Super-Helium-rich Populations and the Origin of Extreme Horizontal-Branch Stars in Globular Clusters

2005 ◽  
Vol 621 (1) ◽  
pp. L57-L60 ◽  
Author(s):  
Young-Wook Lee ◽  
Seok-Joo Joo ◽  
Sang-Il Han ◽  
Chul Chung ◽  
Chang H. Ree ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Horizontal Branch ◽  
Horizontal Branch Stars

scholarly journals Study of the Helium Enrichment in Globular Clusters

2009 ◽  
Vol 5 (S262) ◽  
pp. 27-30
Author(s):  
Aldo A. R. Valcarce ◽  
Márcio Catelan
Keyword(s):  
High Precision ◽  
Globular Clusters ◽  
Stellar Populations ◽  
Horizontal Branch ◽  
Previous Generation ◽  
Horizontal Branch Stars

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.

Spectral Analysis of Supra Horizontal Branch Stars in Globular Clusters

White Dwarfs ◽  
2003 ◽  
pp. 155-156
Author(s):  
M. Ramspeck ◽  
U. Heber ◽  
S. Moehler ◽  
I. N. Reid
Keyword(s):  
Spectral Analysis ◽  
Globular Clusters ◽  
Horizontal Branch ◽  
Horizontal Branch Stars

scholarly journals On the Interpretation of RR Lyrae Properties in Globular Clusters and in Other Population II Systems

1973 ◽  
Vol 21 ◽  
pp. 197-206
Author(s):  
V. Castellani ◽  
P. Giannone ◽  
A. Renzini
Keyword(s):  
Mass Loss ◽  
Globular Clusters ◽  
Horizontal Branch ◽  
Rr Lyrae ◽  
Horizontal Branch Stars

AbstractThe differences in observational parameters of the RR Lyrae variables and horizontal branch stars of globular clusters and other population II systems are considered. A discontinuous behaviour of some parameters is outlined. The Oosterhoff dichotomy and the HB morphology are discussed with regard to a conjecture of mass loss in the pre-HB phase.

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