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

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

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

scholarly journals Carbon and nitrogen abundances of stellar populations in the globular cluster M 2

2012 ◽  
Vol 548 ◽  
pp. A107 ◽  
Author(s):  
C. Lardo ◽  
E. Pancino ◽  
A. Mucciarelli ◽  
A. P. Milone
Keyword(s):  
Globular Cluster ◽  
Stellar Populations ◽  
Carbon And Nitrogen

scholarly journals H-band discovery of additional second-generation stars in the Galactic bulge globular cluster NGC 6522 as observed by APOGEE and Gaia

2019 ◽  
Vol 627 ◽  
pp. A178 ◽  
Author(s):  
J. G. Fernández-Trincado ◽  
O. Zamora ◽  
Diogo Souto ◽  
R. E. Cohen ◽  
F. Dell’Agli ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Second Generation ◽  
Elemental Abundance ◽  
Agb Stars ◽  
Giant Stars ◽  
Abundance Patterns ◽  
Evolution Experiment ◽  
Band Spectra ◽  
Stellar Sources ◽  
Process Element

We present an elemental abundance analysis of high-resolution spectra for five giant stars spatially located within the innermost regions of the bulge globular cluster NGC 6522 and derive Fe, Mg, Al, C, N, O, Si, and Ce abundances based on H-band spectra taken with the multi-object APOGEE-north spectrograph from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. Of the five cluster candidates, two previously unremarked stars are confirmed to have second-generation (SG) abundance patterns, with the basic pattern of depletion in C and Mg simultaneous with enrichment in N and Al as seen in other SG globular cluster populations at similar metallicity. In agreement with the most recent optical studies, the NGC 6522 stars analyzed exhibit (when available) only mild overabundances of the s-process element Ce, contradicting the idea that NGC 6522 stars are formed from gas enriched by spinstars and indicating that other stellar sources such as massive AGB stars could be the primary polluters of intra-cluster medium. The peculiar abundance signatures of SG stars have been observed in our data, confirming the presence of multiple generations of stars in NGC 6522.

The determination of carbon and oxygen abundances in very metal-poor globular cluster giant stars

1992 ◽  
Vol 104 ◽  
pp. 1127 ◽  
Author(s):  
R. A. Bell ◽  
M. M. Briley ◽  
John E. Norris
Keyword(s):  
Globular Cluster ◽  
Giant Stars

Proton‐Capture Nucleosynthesis in Globular Cluster Red Giant Stars

1998 ◽  
Vol 492 (2) ◽  
pp. 575-595 ◽  
Author(s):  
Robert M. Cavallo ◽  
Allen V. Sweigart ◽  
Roger A. Bell
Keyword(s):  
Globular Cluster ◽  
Proton Capture ◽  
Giant Stars ◽  
Red Giant Stars ◽  
Red Giant
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