Issue |
A&A
Volume 377, Number 2, October II 2001
|
|
---|---|---|
Page(s) | 473 - 484 | |
Section | Galactic structure, stellar clusters, and populations | |
DOI | https://doi.org/10.1051/0004-6361:20011135 | |
Published online | 15 October 2001 |
Statistics and supermetallicity: The metallicity of NGC 6791
Department of Physics and Astronomy, N283 ESC, Brigham Young University, Provo, UT 84602-4360, USA
Received:
9
February
2001
Accepted:
9
August
2001
For the old galactic cluster NGC 6791, Peterson & Green ([CITE]) and
Chaboyer et al. ([CITE]) have found that [Fe/H] dex. A
second look at that conclusion is taken in this paper. Zero-point problems
are reviewed for a high-dispersion analysis done by Peterson & Green, and it
is found that accidental errors have not been determined rigorously for the
results of that analysis. It is also noted that in a color-magnitude analysis
performed by Chaboyer et al., the important metallicity range between 0.0 and
+0.3 dex is not explored and hence is not ruled out. Moreover, that
analysis does not yield statistically rigorous results, and it appears that
such results may not be produced in color-magnitude analysis of clusters in
general. Results in the two cited papers and elsewhere are re-evaluated
statistically, with an allowance being made for uncertainty in the cluster
reddening. Apparently the best that can be said at present is that the
cluster metallicity lies in the range from +0.16 to +0.44 dex. This
conclusion is stressed by reviewing the immaturity of the underlying data base.
The premature conclusion for a high metallicity turns out to be due largely to
neglect of accidental errors, though a tendency to ascribe too much weight to
high derived metallicities may also play a role.
Key words: stars: abundances / open clusters and associations: individual: NGC 6791
© ESO, 2001
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