J/AJ/132/902 Abundances of 54 Cepheids (Luck+, 2006)
The distribution of the elements in the galactic disk.
Luck R.E., Kovtyukh V.V., Andrievsky S.M.
<Astron. J., 132, 902-918 (2006)>
=2006AJ....132..902L 2006AJ....132..902L
ADC_Keywords: Stars, variable ; Abundances
Keywords: Cepheids - Galaxy: abundances - Galaxy: evolution - stars: abundances
Abstract:
This paper reports on the spectroscopic investigation of 54 Cepheids,
deriving parameters and abundances. These Cepheids extend previous
samples by about 35% in number and increase the amount of the Galactic
disk coverage, especially in the direction of l∼120°. We find that
there exists in the Galactic disk at that longitude and at a solar
distance of about 3-4kpc a region that has enhanced abundances,
<[Fe/H]≳+0.2, with respect to the local region.
A simple linear fit to all Cepheid data now extant yields a gradient
d[Fe/H]/dR=-0.068±0.003dex/kpc. After consideration of the spatial
abundance inhomogeneities in the sample, we conclude that the best
current estimate of the overall gradient is d[Fe/H]/dR=-0.06dex/kpc.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 57 56 Summary of stars studied (from Simbad)
table6.dat 31 1396 Detailed [x/H] Data for Program Cepheids
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Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Simbad name
12- 13 I2 h RAh Simbad Hour of Right Ascension (J2000.0)
15- 16 I2 min RAm Simbad Minute of Right Ascension (J2000.0)
18- 21 F4.1 s RAs Simbad Second of Right Ascension (J2000.0)
23 A1 --- DE- Simbad Sign of the Declination (J2000.0)
24- 25 I2 deg DEd Simbad Degree of Declination (J2000.0)
27- 28 I2 arcmin DEm Simbad Arcminute of Declination (J2000.0)
30- 31 I2 arcsec DEs Simbad Arcsecond of Declination (J2000.0)
35- 39 F5.2 mag Bmag Simbad B band magnitude
41- 45 F5.2 mag Vmag Simbad V band magnitude
47- 57 A11 --- SpType Simbad MK spectral type
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Source identification
12- 16 A5 --- Ion Ion name
18- 22 F5.2 [-] X/H ? Log of the mean Ion/H number abundance
24- 27 F4.2 [-] e_X/H ? Standard deviation in X/H
29- 31 I3 --- o_X/H ? Number of lines used to derived X/H
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 08-Feb-2008