J/A+A/360/499 Equivalent widths of 9 stars of M 67 (Tautvaisiene+, 2000)
Chemical composition of evolved stars in the open cluster M 67
Tautvaisiene G., Edvardsson B., Tuominen I., Ilyin I.
<Astron. Astrophys. 360, 499 (2000)>
=2000A&A...360..499T 2000A&A...360..499T
ADC_Keywords: Clusters, open ; Equivalent widths
Keywords: stars: abundances - stars: atmospheres - stars: horizontal-branch -
open clusters and associations: individual: M 67
Abstract:
High-resolution spectra of six core helium-burning `clump' stars and
three giants in the open cluster M 67 have been obtained with the
SOFIN spectrograph on the Nordic Optical Telescope to investigate
abundances of up to 25 chemical elements. Abundances of carbon were
studied using the C2 Swan (0,1) band head at 5635.5Å. The
wavelength interval 7980-8130Å with strong CN features was analysed
in order to determine nitrogen abundances and 12C/13C isotope
ratios. The oxygen abundances were determined from the [O I] line at
6300Å. The overall metallicity of the cluster stars was found to be
close to solar ([Fe/H]=-0.03±0.03). Compared with the Sun and other
dwarf stars of the Galactic disk, as well as with dwarf stars of M 67
itself, abundances in the investigated stars suggest that carbon is
depleted by about 0.2dex, nitrogen is enhanced by about 0.2dex and
oxygen is unaltered. Among other mixing-sensitive chemical elements an
overabundance of sodium may be suspected. The mean C/N and 12C/13C
ratios are lowered to the values of 1.7±0.2 and 24±4 in the giants
and to the values of 1.4±0.2 and 16±4 in the clump stars. These
results suggest that extra mixing of CN-cycled material to the stellar
surface takes place after the He-core flash. Abundances of heavy
chemical elements in all nine stars were found to be almost identical
and close to solar.
Objects:
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RA (2000) DE Designation(s)
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08 48 26.0 +12 24 54 F84 = Cl* NGC 2682 FBC 84
08 48 35.4 +11 38 12 F141 = Cl* NGC 2682 FBC 141
08 48 36.4 +11 48 06 F151 = Cl* NGC 2682 FBC 151
08 48 29.4 +12 02 54 F105 = Cl* NGC 2682 FBC 105
08 48 29.5 +11 54 52 F108 = Cl* NGC 2682 FBC 108
08 48 37.8 +12 24 06 F164 = Cl* NGC 2682 FBC 164
08 48 38.4 +11 41 14 F170 = Cl* NGC 2682 FBC 170
08 48 42.6 +11 38 14 F224 = Cl* NGC 2682 FBC 224
08 48 42.8 +12 09 14 F226 = Cl* NGC 2682 FBC 226
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 33 132 Equivalent widths of lines measured from
spectra of resolving power 60000
table3.dat 59 179 Equivalent widths of lines measured from
spectra of resolving power 30000
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See also:
J/AJ/112/628 : Deep Wide-Field Spectrophotometry of M67 (Fan+ 1996)
Byte-per-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 F6.2 --- Element Line identification: chemical element and
ionisation stage (e.g. 23.01 means singly
ionised vanadium, i.e. V II)
8- 14 F7.2 0.1nm Lambda Wavelength (Angstroms)
16- 18 I3 0.1pm EWF84 ?=999 Equivalent width for the clump star F84
20- 22 I3 0.1pm EWF141 Equivalent width for the clump star F141
24- 26 I3 0.1pm EWF151 Equivalent width for the clump star F151
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Byte-per-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.2 --- Element Line identification: chemical element and
ionisation stage (e.g. 23.01 means singly
ionised vanadium, i.e. V II)
8- 14 F7.2 0.1nm Lambda Wavelength (Angstroms)
16- 18 I3 0.1pm EWF84 ?=999 Equivalent width for the clump star F84
20- 22 I3 0.1pm EWF105 Equivalent width for the giant star F105
24- 26 I3 0.1pm EWF108 Equivalent width for the giant star F108
28- 30 I3 0.1pm EWF141 Equivalent width for the clump star F141
32- 34 I3 0.1pm EWF151 Equivalent width for the clump star F151
36- 38 I3 0.1pm EWF164 Equivalent width for the clump star F164
40- 42 I3 0.1pm EWF170 Equivalent width for the giant star F170
44- 46 I3 0.1pm EWF224 Equivalent width for the clump star F224
48- 50 I3 0.1pm EWF266 Equivalent width for the clump star F266
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Acknowledgements: Grazina Tautvaisiene
(End) Patricia Bauer [CDS] 28-Aug-2000