On the gap in horizontal branches at B – V about zero
نویسنده
چکیده
It is proposed that the gap observed in the horizontal branch sequence of many globular clusters at B − V about zero is due to a surface phenomenon. Stars on the hotter side of the gap – Teff & 10000 K – have an atmospheric chemical composition altered as in peculiar A and B stars. The appearance of a convective regime in the surface layers at the temperature and gravity of the gap cancel the peculiarities: it is proposed that the ensuing changes in surface physical conditions give origin to the observed gap.
منابع مشابه
On the zero forcing number of some Cayley graphs
Let Γa be a graph whose each vertex is colored either white or black. If u is a black vertex of Γ such that exactly one neighbor v of u is white, then u changes the color of v to black. A zero forcing set for a Γ graph is a subset of vertices Zsubseteq V(Γ) such that if initially the vertices in Z are colored black and the remaining vertices are colored white, then Z changes the col...
متن کاملEffects of Impeller Gap on Rotor Vibration in a High Speed Centrifugal Compressor: A Numerical and Experimental Analysis (TECHNICAL NOTE)
Centrifugal compressors produce high pressure ratio and rotate at speeds. So, a tiny unbalance can produce severe vibration. In this paper, effects of impeller gap on rotor vibration in a high speed centrifugal compressor is investigated. For this purpose, a numerical and experimental analysis are carried out. The moving reference frame method in FLUENT software is used for modeling of geometri...
متن کاملThe Effect of Different Treatments of Indole-3-Butyric Acid (IBA) on Rooting of Clerodendron Phlomidis
The research has been done for assessment of effects of different concentrations of Indole-3-Butyric Acid (IBA) on rhizogenesis of scions of C. Phlomidis in 2010. The research has been done on Randomized Complete-blocks for five replications and three treatments with zero, 2000ppm and 3000pmm concentration. Different characters such as number of root of each scion, length of root, length of ne...
متن کاملThe Effect of Different Treatments of Indole-3-Butyric Acid (IBA) on Rooting of Clerodendron Phlomidis
The research has been done for assessment of effects of different concentrations of Indole-3-Butyric Acid (IBA) on rhizogenesis of scions of C. Phlomidis in 2010. The research has been done on Randomized Complete-blocks for five replications and three treatments with zero, 2000ppm and 3000pmm concentration. Different characters such as number of root of each scion, length of root, length of ne...
متن کاملQuality Gap in Educational Services at Zahedan University of Medical Sciences: Students Viewpoints about Current and Optimal Condition
Introduction. The first basic step in developing any quality improvement program is determining the quality gap and, adopting strategies for removing or reducing this gap. This study was performed to determine the quality gap in educational services at Zahedan University of Medical Sciences, based on students’ perceptions and expectations. Methods. In this cross-sectional descriptive study, 38...
متن کامل