SIMBAD references

2013ApJ...769...40C - Astrophys. J., 769, 40 (2013/May-3)

Potassium in globular cluster stars: comparing normal clusters to the peculiar cluster NGC 2419.

CARRETTA E., GRATTON R.G., BRAGAGLIA A., D'ORAZI V., LUCATELLO S., SOLLIMA A. and SNEDEN C.

Abstract (from CDS):

Two independent studies recently uncovered two distinct populations among giants in the distant, massive globular cluster (GC) NGC 2419. One of these populations has normal magnesium (Mg) and potassium (K) abundances for halo stars: enhanced Mg and roughly solar K. The other population has extremely depleted Mg and very enhanced K. To better anchor the peculiar NGC 2419 chemical composition, we have investigated the behavior of K in a few red giant branch stars in NGC 6752, NGC 6121, NGC 1904, and ω Cen. To verify that the high K abundances are intrinsic and not due to some atmospheric features in giants, we also derived K abundances in less evolved turn-off and subgiant stars of clusters 47 Tuc, NGC 6752, NGC 6397, and NGC 7099. We normalized the K abundance as a function of the cluster metallicity using 21 field stars analyzed in a homogeneous manner. For all GCs of our sample, the stars lie in the K-Mg abundance plane on the same locus occupied by the Mg-normal population in NGC 2419 and by field stars. This holds for both giants and less-evolved stars. At present, NGC 2419 seems unique among GCs.

Abstract Copyright:

Journal keyword(s): globular clusters: general - globular clusters: individual (NGC 6752, NGC 6121, NGC 1904, NGC 2419, NGC 6397, NGC 104, NGC 7099) - stars: abundances - stars: evolution - stars: Population II

VizieR on-line data: <Available at CDS (J/ApJ/769/40): table1.dat>

Nomenclature: Table 1: [CGB2013] NGC 7099 NNN N=8 among (Nos 789-946).

Simbad objects: 113

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2021.05.07-04:12:45

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