scholarly journals Carbon and nitrogen abundances in Population I G and K giant stars from DDO photometry

1982 ◽  
Vol 201 (2) ◽  
pp. 253-263 ◽  
Author(s):  
Jerry Bonnell ◽  
R. A. Bell
Keyword(s):  
Carbon And Nitrogen ◽  
Giant Stars

Carbon and nitrogen abundances in giant stars of the metal-poor globular cluster M92

1982 ◽  
Vol 49 ◽  
pp. 207 ◽  
Author(s):  
D. F. Carbon ◽  
W. Romanishin ◽  
G. E. Langer ◽  
D. Butler ◽  
E. Kemper ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Carbon And Nitrogen ◽  
Giant Stars

Carbon and nitrogen abundances in giant stars of the metal-poor globular cluster M15

1983 ◽  
Vol 266 ◽  
pp. 144 ◽  
Author(s):  
D. V. Trefzger ◽  
G. E. Langer ◽  
D. F. Carbon ◽  
N. B. Suntzeff ◽  
R. P. Kraft
Keyword(s):  
Globular Cluster ◽  
Carbon And Nitrogen ◽  
Giant Stars

scholarly journals Derivation of Abundances Through Photometric and Spectroscopic Methods

1976 ◽  
Vol 72 ◽  
pp. 49-65
Author(s):  
R. A. Bell
Keyword(s):  
Globular Cluster ◽  
Spectroscopic Methods ◽  
Intermediate Band ◽  
Carbon And Nitrogen ◽  
Giant Stars ◽  
A Value ◽  
Synthetic Spectra ◽  
Isotopic Shifts ◽  
Cool Stars ◽  
K Giants

Several points of detail which affect stellar abundance determinations are discussed. In particular, the importance of including the effects of hyperfine structure and isotopic shifts when considering the lines of some elements is stressed.The abundance determinations for F dwarfs by Bell and Peytremann, who use theoretical calibrations for intermediate band photometry, and Nissen, who observes very narrow spectral intervals, are intercompared. The agreement between Bell and Nissen, who have 46 stars in common, is quite satisfactory.Recent work on carbon and nitrogen abundances in cool stars is described. The suggestion of Hearnshaw, that [C/H] = 1.5 [Fe/H] for disc stars with −0.7 < [Fe/H] < 0.4, is compared with recent results by Clegg. Whilst Clegg's results are quite precise, they neither confirm nor deny Hearnshaw's suggestion. Work by Branch and Bell on K giants shows that [C/Fe] = 0, or a constant, for the stars in the sample. A value of about 7 for the C12/C13 ratio in the atmosphere of Arcturus has now been confirmed by several authors and Lambert and his collaborators have determined this ratio for several K giants.The suggestion by Spinrad, Taylor and others that the M67 dwarfs are more metal-rich than the Hyades, i.e. that they are super-metal-rich or SMR, seems to be erroneous. However some SMR stars, such as 31 Aql, certainly exist even though there is still some uncertainty in the precise abundance of strong CN stars such as μ Leo.Examples of synthetic spectra for metal-deficient giant stars are given and a theoretical colour-colour diagram is compared with observations of globular cluster and Draco stars.

Carbon and nitrogen abundances in red giant stars in the globular cluster 47 Tucanae

1979 ◽  
Vol 232 ◽  
pp. 428 ◽  
Author(s):  
R. J. Dickens ◽  
R. A. Bell ◽  
B. Gustafsson
Keyword(s):  
Globular Cluster ◽  
Carbon And Nitrogen ◽  
Giant Stars ◽  
Red Giant Stars ◽  
Red Giant

Metabolic signalling and the partitioning of resources in plant storage organs

1999 ◽  
Vol 133 (3) ◽  
pp. 243-249 ◽  
Author(s):  
NIGEL G. HALFORD
Keyword(s):  
Dry Weight ◽  
Wild Relatives ◽  
Crop Plants ◽  
Wild Plants ◽  
Young Plant ◽  
Carbon And Nitrogen ◽  
Cultivated Potato ◽  
Metabolic Signalling ◽  
Storage Organs ◽  
Plant Storage

The most important harvested organs of crop plants, such as seeds, tubers and fruits, are often described as assimilate sinks. They play little or no part in the fixation of carbon through the production of sugars through photosynthesis, or in the uptake of nitrogen and sulphur, but import these assimilated resources to support metabolism and to store them in the form of starch, oils and proteins. Wild plants store resources in seeds and tubers to later support an emergent young plant. Cultivated crops are effectively storing resources to provide us with food and many have been bred to accumulate much more than would be required otherwise. For example, approximately 80% of a cultivated potato plant's dry weight is contained in its tubers, ten times the proportion in the tubers of its wild relatives (Inoue & Tanaka 1978). Cultivation and breeding has brought about a shift in the partitioning of carbon and nitrogen assimilate between the organs of the plant.

Surface Brightness Scale of Galactic Cepheids

1999 ◽  
Vol 190 ◽  
pp. 561-562
Author(s):  
G. P. Di Benedetto
Keyword(s):  
Surface Brightness ◽  
Variable Stars ◽  
Giant Stars ◽  
Near Ir

An accurate calibration of the surface brightness scaleSVas a function of the near-IR color (V–K) has been recently measured for non-variable Galactic dwarf and giant stars. It can be shown that this correlation can be applied to theSVscale of Galactic Cepheid variable stars, which are of major cosmological interest.

Precipitation in silicon: Microanalysis

1988 ◽  
Vol 46 ◽  
pp. 474-475
Author(s):  
R.W. Carpenter
Keyword(s):  
Transition Metals ◽  
Spatial Resolution ◽  
Thin Foil ◽  
Precipitation Reaction ◽  
High Current ◽  
Reaction Products ◽  
Carbon And Nitrogen ◽  
Dielectric Layers ◽  
Precipitation Processes ◽  
Areas Of Interest

Interest in precipitation processes in silicon appears to be centered on transition metals (for intrinsic and extrinsic gettering), and oxygen and carbon in thermally aged materials, and on oxygen, carbon, and nitrogen in ion implanted materials to form buried dielectric layers. A steadily increasing number of applications of microanalysis to these problems are appearing. but still far less than the number of imaging/diffraction investigations. Microanalysis applications appear to be paced by instrumentation development. The precipitation reaction products are small and the presence of carbon is often an important consideration. Small high current probes are important and cryogenic specimen holders are required for consistent suppression of contamination buildup on specimen areas of interest. Focussed probes useful for microanalysis should be in the range of 0.1 to 1nA, and estimates of spatial resolution to be expected for thin foil specimens can be made from the curves shown in Fig. 1.

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