J/A+A/392/491 Galactic abundance gradient. III. (Andrievsky+, 2002)
Using Cepheids to determine the galactic abundance gradient.
III. First results for the outer disc
Andrievsky S.M., Kovtyukh V.V., Luck R.E., Lepine J.R.D., Maciel W.J.,
Beletsky Yu.V.
<Astron. Astrophys. 392, 491 (2002)>
=2002A&A...392..491A 2002A&A...392..491A
ADC_Keywords: Stars, variable ; Stars, supergiant ; Abundances
Keywords: stars: abundances - stars: Cepheids - Galaxy: abundances -
Galaxy: evolution
Abstract:
As a continuation of our previous work, which concerned the radial
abundance distribution in the galactic disc over the distances 4-10kpc
this paper presents the first results on the metallicity in the outer
disc (RG>10kpc).
Based on high-resolution spectra obtained for 19 distant Cepheids
we sampled galactocentric distances from 10 to 12 kpc. Combined with
the results of our previous work on the inner and middle parts of the
galactic disc, the present data enable one to study the structure of
the radial abundance distribution over a large baseline.
In particular, we find indications of a discontinuity in the radial
abundance distribution for iron as well as a number of the other
elements. The discontinuity is seen at a galactocentric distance
RG=10kpc. This finding supports the results reported earlier by
Twarog et al. (1997AJ....114.2556T 1997AJ....114.2556T).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
objects.dat 68 19 Program stars: details of the observations and
atmosphere parameters
objects.tex 74 36 LaTeX version of objects.dat
tablea1.dat 43 639 Abundances
tablea1.tex 154 269 LaTeX version of tablea1.dat
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See also:
J/A+A/381/32 : Galactic Cepheid abundances (Andrievsky+, 2002)
Byte-by-byte Description of file: objects.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Star Star name
9 A1 --- n_Star [*] Individual note (1)
13- 21 F9.6 d Per Pulsational period
23- 28 F6.3 mag Vmag Visual magnitude
31- 34 I4 s ExpTime Exposure time
37- 49 F13.5 d JD Julian date of observation
51- 55 F5.3 --- phi Phase
57- 60 I4 K Teff Effective temperature
62- 64 F3.1 [cm/s2] logg Logarithm of the gravity (g in cm/s^2)
66- 68 F3.1 km/s Vturb Microturbulent velocity
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Note (1): For V504 Mon (classified as s-Cepheid) the fundamentalized period
is given (P0=P1/0.71), P(observ)=P1=2.77405.
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Star Star name
12- 17 A6 --- Ion Ion
18 A1 --- l_[M/H] Limit flag on [M/H]
19- 23 F5.2 [Sun] [M/H] ? Relative-to-solar abundance
24 A1 --- u_[M/H] Uncertainty flag on [M/H]
27- 30 F4.2 [Sun] e_[M/H] ? Standard deviation
33- 35 I3 --- Nlines ? Number of lines used in analysis
37 A1 --- l_(El/H) Limit flag on (El/H)
38- 41 F4.2 [---] (El/H) ? Absolute elemental abundance (H=12)
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Acknowledgements: Sergei M. Andrievsky
References:
Andrievsky et al., Paper I 2002A&A...381...32A 2002A&A...381...32A, J/A+A/381/32
Andrievsky et al., Paper II 2002A&A...384..140A 2002A&A...384..140A
(End) Patricia Bauer [CDS] 03-Sep-2002