SIMBAD references

2002A&A...390...91B - Astronomy and Astrophysics, volume 390, 91-101 (2002/7-4)

The lithium content of the globular cluster NGC 6397.

BONIFACIO P., PASQUINI L., SPITE F., BRAGAGLIA A., CARRETTA E., CASTELLANI V., CENTURION M., CHIEFFI A., CLAUDI R., CLEMENTINI G., D'ANTONA F., DESIDERA S., FRANCOIS P., GRATTON R.G., GRUNDAHL F., JAMES G., LUCATELLO S., SNEDEN C. and STRANIERO O.

Abstract (from CDS):

We make use of high resolution, high signal-to-noise ratio spectra of 12 turn-off stars in the metal-poor globular cluster NGC 6397 to measure its lithium content. We conclude that they all have the same lithium abundance A(Li)=2.34 with a standard deviation of 0.056dex. We use this result, together with Monte Carlo simulations, to estimate that the maximum allowed intrinsic scatter is of the order of 0.035dex. This is a new stringent constraint to be fulfilled by stellar models which predict Li depletion. We argue that although a mild depletion of 0.1-0.2dex, as predicted by recent models, cannot be ruled out, there is no compelling reason for it. This fact, together with the good agreement with the Li abundance observed in field stars, supports the primordial origin of lithium in metal-poor stars. Taking the above value as the primordial lithium abundance implies a cosmic baryonic density which is either Ωbh2=0.016±0.004 or Ωbh2=0.005+0.0026–0.0006, from the predictions of standard big bang nucleosynthesis. The high baryonic density solution is in agreement with recent results on the primordial abundance of deuterium and 3He and on the estimates derived from the fluctuations of the cosmic microwave background.

Abstract Copyright:

Journal keyword(s): diffusion - stars: abundances - stars: atmospheres - stars: Population II - Galaxy: globular clusters: NGC 6397 - cosmology: observations

CDS comments: Table 1, 2: The 5 stars are Cl* NGC 6397 GVS NNNNNN. Table 2 : C4602 is a misprint for C4062 = NGC 6397 4062. A611 and A853 = Cl* NGC 6397 ABCPO 611,853. Other A objects = Cl* NGC 6397 ALA NNNN.

Simbad objects: 29

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2020.09.21-13:01:15

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