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J/A+A/413/159       Galactic abundance gradient. V.          (Andrievsky+, 2004)

The Galactic abundance gradient from Cepheids. V. Transition zone between 10 and 11 kpc. Andrievsky S.M., Luck R.E., Martin P., Lepine J.R.D. <Astron. Astrophys., 413, 159-172 (2004)> =2004A&A...413..159A
ADC_Keywords: Stars, variable ; Abundances, peculiar Keywords: stars: abundances - Galaxy: abundances - Galaxy: evolution - stars: variables: Cepheids Abstract: This paper reports on the spectroscopic investigation of 12 Cepheids which are situated in the crucial region of galactocentric distances from 9kpc to 12kpc, where according to our previous results (Andrievsky et al., 2002, Cat. J/A+A/392/491; Luck et al., 2003A&A...401..939L) the radial metallicity distribution experiences an obvious change. In particular, the wriggle in the iron abundance distribution is found to fall approximately at galactocentric distances 10-11kpc (assuming galactocentric distance of the Sun kpc). Within the transition zone from 10 to 11kpc the relative-to-solar iron abundance decreases approximately to -0.2dex. The new sample of stars, analyzed in present paper, gives results supporting the previous conclusion about the multimodal character of the metallicity distribution in galactic disc. Using a quite simple consideration of galactic chemical evolution we show that the observed distribution can be explained in the framework of a model which includes the spiral arms. In particular, the wriggle feature associated with 11 kpc can be interpreted as a change of metallicity level in the vicinity of the galactic corotation resonance. Description: The observations were carried out on 1-5 February 2003 with the 3.6-m Canada-France-Hawaii Telescope. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file stars.dat 70 13 Star positions and magnitudes (from Simbad) tablea1.dat 34 299 Individual elemental abundances for program stars tablea1.tex 136 208 LaTeX version of the table
See also: J/A+A/381/32 : Galactic Cepheid abundances. I. (Andrievsky+, 2002) J/A+A/392/491 : Galactic abundance gradient. III. (Andrievsky+, 2002) Byte-by-byte Description of file: stars.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Name Object 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
Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 8 A8 --- Name Star name 10- 14 F5.2 --- Ion Ion atomic number (1) 16- 20 F5.2 [Sun] [M/H] ? Relative-to-solar abundance 22- 25 F4.2 [Sun] e_[M/H] ? rms uncertainty on [M/H] 27- 28 I2 --- Nline ? Number of lines used 30- 33 F4.2 --- (M/H) ? Absolute abundance (in the scale log(H)=12.00)
Note (1): Ion atomic number: 6.00=C, 8.00=O, 11.00=Na, 14.00=Si, 14.01=Si+ 16.00=S, 20.00=Ca, 21.00=Sc, 21.01=Sc+ 22.00=Ti, 23.00=V, 24.00=Cr, 24.01=Cr+ 25.00=Mn, 26.00=Fe, 26.01=Fe+ 27.00=Co, 28.00=Ni, 40.01=Zr+ 57.01=La+ 58.01=Ce+ 60.01=Nd+ 63.01=Eu+
Acknowledgements: Sergei Andrievsky References: Andrievski et al., Paper I 2002A&A...381...32A, Cat. J/A+A/381/32 Andrievski et al., Paper II 2002A&A...384..140A Andrievski et al., Paper III 2002A&A...392..491A, Cat. J/A+A/392/491 Luck et al., Paper Iv 2003A&A...401..939L
(End) Patricia Bauer [CDS] 22-Dec-2003
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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