J/A+A/380/578 Equiv. widths of 13 horizontal branch stars (Tautvaisiene+, 2001)
Chemical composition of red horizontal branch stars in the thick disk
of the Galaxy
Tautvaisiene G., Edvardsson B., Tuominen I., Ilyin I.
<Astron. Astrophys. 380, 578 (2001)>
=2001A&A...380..578T 2001A&A...380..578T
ADC_Keywords: Stars, horizontal branch ; Stars, atmospheres ; Abundances
Keywords: stars: abundances - stars: atmospheres - stars: horizontal-branch -
Galaxy: formation
Abstract:
High-resolution spectra of 13 core helium-burning stars in the thick
disk of the Galaxy have been obtained with the SOFIN spectrograph on
the Nordic Optical Telescope to investigate abundances of up to 22
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. Abundances
in the investigated stars suggest that carbon is depleted by about
0.3dex, nitrogen is enhanced by more than 0.4dex and oxygen is
unaltered. The 12C/13C ratios are lowered and lie between values 3 and
7 which is in agreement with "cool bottom processing" predictions
(Boothroyd & Sackmann, 1999ApJ...510..232B 1999ApJ...510..232B). The C/N ratios in the
investigated stars are lowered to values between 0.7 and 1.2 which is
less than present day theoretical predictions and call for further
studies of stellar mixing processes. Abundance ratios of O, Mg, Eu and
other heavy chemical elements to iron in the investigated stars show a
pattern characteristic of thick disk stars. The results provide
evidence that the thick disk population has a distinct chemical
history from the thin disk. The onset of the bulk of SN Ia is
suggested to appear at [Fe/H]~-0.6dex.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 58 13 Star positions and magnitudes (from Simbad)
table1.dat 66 204 Equivalent widths of lines
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See also:
J/A+A/360/499 : Equivalent widths of 9 stars of M 67 (Tautvaisiene+, 2000)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Star name
15- 16 I2 h RAh Right ascension (J2000.0)
18- 19 I2 min RAm Right ascension (J2000.0)
21- 24 F4.1 s RAs Right ascension (J2000.0)
26 A1 --- DE- Declination sign (J2000.0)
27- 28 I2 deg DEd Declination (J2000.0)
30- 31 I2 arcmin DEm Declination (J2000.0)
33- 34 I2 arcsec DEs Declination (J2000.0)
38- 42 F5.2 mag Bmag ? B magnitude
44- 48 F5.2 mag Vmag ? V magnitude
50- 70 A21 --- SpType Spectral type
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Byte-per-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 F6.2 --- Element Line identification (1)
8- 14 F7.2 0.1nm Lambda Wavelength (Angstroms)
16- 18 I3 0.1pm EW1 ?=999 Equivalent width (milliAngstrom) for the
star BD +25 2436
20- 22 I3 0.1pm EW2 ?=999 Equivalent width for the star BD +25 2459
24- 26 I3 0.1pm EW3 ?=999 Equivalent width for the star BD +25 2502
28- 30 I3 0.1pm EW4 ?=999 Equivalent width for the star BD +27 2057
32- 34 I3 0.1pm EW5 ?=999 Equivalent width for the star BD +28 2079
36- 38 I3 0.1pm EW6 ?=999 Equivalent width for the star BD +29 2231
40- 42 I3 0.1pm EW7 ?=999 Equivalent width for the star BD +29 2294
44- 46 I3 0.1pm EW8 ?=999 Equivalent width for the star BD +29 2321
48- 50 I3 0.1pm EW9 ?=999 Equivalent width for the star BD +33 2280
52- 54 I3 0.1pm EW10 ?=999 Equivalent width for the star BD +34 2371
56- 58 I3 0.1pm EW11 ?=999 Equivalent width for the star BD +36 2303
60- 62 I3 0.1pm EW12 ?=999 Equivalent width for the star HD 104783
64- 66 I3 0.1pm EW13 ?=999 Equivalent width for the star HD 105944
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Note (1): Chemical element and ionisation stage (e.g. 23.01 means singly
ionised vanadium, or V II)
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Acknowledgements: Grazina Tautvaisiene
(End) Patricia Bauer [CDS] 10-Dec-2001