J/MNRAS/437/2106 Barium abundance in Galactic Cepheids (Andrievsky+, 2014)
Barium in Cepheids: new data on the abundance distribution in the Galactic disc.
Andrievsky S.M., Luck R.E., Korotin S.A.
<Mon. Not. R. Astron. Soc., 437, 2106-2110 (2014)>
=2014MNRAS.437.2106A 2014MNRAS.437.2106A
ADC_Keywords: Stars, variable ; Abundances
Keywords: stars: abundances - stars: variables: Cepheids - Galaxy: disc -
Galaxy: evolution
Abstract:
Using an Non-Local Thermodynamic Equilibrium (NLTE) analysis and a
homogenous spectral data base, we have determined Ba abundances in a
sample of 210 Galactic Cepheids and related objects. We confirm the
previous result reported in Andrievsky et al. that the barium
distribution in the range of Galactocentric distances from 5 to 18kpc
shows very small gradient value. The value determined here -
d[Ba/H]/dR~-0.01dex/kpc - is smaller than that for other s-process
elements, such as La, Pr, Nd and Sm (Luck & Lambert, 2011AJ....142..136L 2011AJ....142..136L,
Cat. J/AJ/142/136), that typically show gradients of -0.03dex/kpc.
Description:
Our present star sample includes 303 high-resolution spectra of 210
classical Cepheids and other related objects. The related objects are
primarily type II Cepheids. The spectra are part of the data base
previously used for abundance analysis by Luck & Lambert
(2011AJ....142..136L 2011AJ....142..136L, Cat. J/AJ/142/136). These spectra were obtained
with Hobby-Eberly Telescope and its High-Resolution Spectrograph. The
spectra span a wavelength range 400-785nm with a nominal resolution
of 30000 and a per pixel signal-to-noise ratio of 100 or greater.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 51 305 Parameters and abundances for programme Cepheids
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See also:
J/AJ/142/136 : Spectroscopy of Cepheids. l=30-250° (Luck+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Name Star name
14 A1 --- n_Name [*+] Non-Cepheid, or lacking distance (1)
16- 20 F5.3 --- Phase [0/1]? Phase (2)
22- 25 I4 K Teff [4597/6666] Effective temperature (2)
27- 30 F4.2 [cm/s2] logg [0.8/3.2] logarithm of surface gravity (2)
32- 35 F4.2 km/s vt [2/9] Microturbulent velocity (2)
37- 40 F4.2 [-] epsFe Iron abundance in the scale log(H)=12 (2)
42- 45 F4.2 [-] epsBa ? Barium abundance in the scale log(H)=12
47- 51 F5.2 kpc Rg [5/18]? Galactocentric distance (2)
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Note (1): Notes as follows:
* = AU Peg, BC Aql, DR Cep, QQ Per, EK Del, GP Per, and RW Cam are also
from Luck & Lambert (2011, Cat. J/AJ/142/136) but are W Vir stars and
hence not included in the gradient calculations.
+ = The Guide Star Catalog (GSC) objects are also from Luck & Lambert
(2011, Cat. J/AJ/142/136). They are Cepheids from Wils & Greaves
(2004IBVS.5512....1W 2004IBVS.5512....1W) but have insufficient data to compute a
distance. There are a few Cepheids in the named variables that also
lack distances due to missing data.
Note (2): Phases, effective temperatures, gravities, mictroturbulent
velocities, iron abundances, and galactocentric distances from
Luck & Lambert 2011 (J/AJ/142/136).
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 23-Nov-2014