2006A&A...450..557R


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.14CET16:26:31

2006A&A...450..557R - Astronomy and Astrophysics, volume 450, 557-567 (2006/5-1)

Element abundances of unevolved stars in the open cluster M 67.

RANDICH S., SESTITO P., PRIMAS F., PALLAVICINI R. and PASQUINI L.

Abstract (from CDS):

The star-to-star scatter in lithium abundances observed among otherwise similar stars in the solar-age open cluster M 67 is one of the most puzzling results in the context of the so called ``lithium problem''. Among other explanations, the hypothesis has been proposed that the dispersion in Li is due to star-to-star differences in Fe or other element abundances which are predicted to affect Li depletion. The primary goal of this study is the determination of the metallicity ([Fe/H]), α- and Fe-peak abundances in a sample of Li-poor and Li-rich stars belonging to M 67, in order to test this hypothesis. By comparison with previous studies, the present investigation also allows us to check for intrinsic differences in the abundances of evolved and unevolved cluster stars and to draw more secure conclusions on the abundance pattern of this cluster. We have carried out an analysis of high resolution UVES/VLT spectra of eight unevolved and two slightly evolved cluster members using MOOG and measured equivalent widths. For all the stars we have determined [Fe/H] and element abundances for O, Na, Mg, Al, Si, Ca, Ti, Cr and Ni. We find an average metallicity [Fe/H]=0.03±0.01, in very good agreement with previous determinations. All the [X/Fe] abundance ratios are very close to solar. The star-to-star scatter in [Fe/H] and [X/Fe] ratios for all elements, including oxygen, is lower than 0.05dex, implying that the large dispersion in lithium among cluster stars is not due to differences in these element abundances. We also find that, when using a homogeneous scale, the abundance pattern of unevolved stars in our sample is very similar to that of evolved stars, suggesting that, at least in this cluster, RGB and clump stars have not undergone any chemical processing. Finally, our results show that M 67 has a chemical composition that is representative of the solar neighborhood.

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: evolution - open clusters and associations: individual: M 67

Simbad objects: 18

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Number of rows : 18

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NGC 188 OpC 00 48 26 +85 15.3           ~ 796 0
2 NGC 752 OpC 01 57 41 +37 47.1           ~ 526 0
3 HD 32347 PM* 05 03 07.6578243018 +13 43 50.412068300   9.372 8.596 8.182 7.810 K0 87 0
4 NGC 2682 106 V* 08 51 17.3468039630 +11 47 00.666533935 13.671 13.638 13.069   12.393 ~ 51 0
5 NGC 2682 OpC 08 51 18 +11 48.0           ~ 1990 0
6 NGC 2682 115 V* 08 51 18.5413357444 +11 49 21.514285478 13.309 13.26 12.645 12.274 11.924 F9IV 62 0
7 NGC 2682 127 V* 08 51 20.1237965086 +11 46 41.753630000 13.336 13.32 12.776   12.08 ~ 68 0
8 NGC 2682 128 * 08 51 20.3300303333 +11 45 52.481234197 13.782 13.72 13.244   12.445 ~ 51 0
9 NGC 2682 129 * 08 51 20.5508573366 +11 46 04.890695678 13.826 13.75 13.308   12.490 ~ 49 0
10 Cl* NGC 2682 ES I-54 * 08 51 21.7685361209 +11 44 05.090717500 14.976 14.89 14.186   13.421 ~ 28 0
11 NGC 2682 140 Ro* 08 51 22.0511495782 +11 46 41.010432677 13.811 13.797 13.189 12.834 12.496 ~ 53 0
12 NGC 2682 209 * 08 51 39.0508901187 +11 47 55.414119410 14.461 14.33 13.783   12.992 ~ 38 0
13 Cl* NGC 2682 ES II-14 * 08 51 41.4951945620 +11 47 36.174961813 14.804 14.71 14.188   13.382 G2V 28 0
14 NGC 2682 226 * 08 51 44.0075673304 +11 46 24.536468173 13.749 13.549 12.790   11.928 G0 48 0
15 NGC 3680 OpC 11 25 38 -43 14.6   8.40 7.6     ~ 285 0
16 Cl Collinder 261 OpC 12 38 11.5 -68 22 01     10.7     ~ 152 0
17 NGC 6253 OpC 16 59 05 -52 42.0     10.2     ~ 141 0
18 IC 4651 OpC 17 24 49 -49 56.0           ~ 306 0

    Equat.    Gal    SGal    Ecl

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2019.11.14-16:26:31

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