J/A+A/580/A17 α-element abundances of Cepheid stars (Genovali+, 2015) On the alpha-element gradients of the Galactic thin disk using Cepheids. Genovali K., Lemasle B., da Silva R., Bono G., Fabrizio M., Bergemann M., Buonanno R., Ferraro I., Francois P., Iannicola G., Inno L., Laney C.D., Kudritzki R.-P., Matsunaga N., Nonino M., Primas F., Romaniello M., Urbaneja M.A., Thevenin F. =2015A&A...580A..17G ADC_Keywords: Stars, variable ; Milky Way ; Abundances ; Spectroscopy Keywords: stars: abundances - stars: variables: Cepheids - stars: oscillations - Galaxy: disk - open clusters and associations: general Abstract: We present new homogeneous measurements of Na, Al, and three alpha-elements (Mg, Si, Ca) for 75 Galactic Cepheids, complemented with Cepheid abundances available in the literature, for a total of 439 stars. The abundances are based on high spectral resolution (R∼38000) and high signal-to-noise ratio (S/N∼50-300) spectra collected with UVES at ESO VLT. Special attention was given to providing a homogeneous abundance scale for these five elements plus iron. In addition, accurate Galactocentric distances (RG) based on near-infrared photometry are also available for all the Cepheids in the sample. We found that these five elements display well-defined linear radial gradients and modest standard deviations over the entire range of RG. The [element/Fe] abundance ratios are constant across the entire thin disk and over the entire period range; only the Ca radial distribution shows marginal evidence of slopes. These results indicate that the chemical enrichment history of iron and of the quoted elements has been quite similar across the four quadrants of the Galactic thin disk, and very homogenous within the range in age covered by the Cepheids (∼10-300Myr). Finally, we also find that Cepheid abundances agree with similar abundances for thin and thick disk dwarf stars, and they follow the typical Mg-Al and Na-O correlations. Description: The abundances of Fe, Na, Al, and three alpha elements (Mg, Si, Ca) for our sample of 75 Cepheids plus data available in the literature for other 364 Cepheids are shown. We first show the abundances derived based on individual spectra for the 75 stars, then the averaged values, and finally the data from the literature. The original abundances available in the literature were rescaled according to the zero-point differences listed in Table 3. The priority was given in the following order: we first adopt the abundances provided by our group, this study (TS) and Lemasle et al. (2013A&A...558A..31L, LEM), and then those provided by the other studies, Luck & Lambert (2011AJ....142..136L, LIII), Luck et al. (2011AJ....142...51L, LII), and Yong et al. (2006AJ....131.2256Y, YON). File Summary: FileName Lrecl Records Explanations ReadMe 80 . This file table1.dat 103 122 Fe, Na, Al, Mg, Si, and Ca abundances for the 75 Cepheids based on individual spectra table2.dat 94 75 Mean abundances of Fe, Na, Al, Mg, Si, and Ca for the 75 Cepheids table5.dat 96 439 Na, Al, Mg, Si, and Ca abundances for the whole sample of 439 Galactic Cepheids (the current 75 plus 364 from the literature) See also: J/AJ/142/51 : Galactic Cepheids abundance variations (Luck+, 2011) J/AJ/142/136 : Spectroscopy of Cepheids. l=30-250° (Luck+, 2011) Byte-by-byte Description of file: table1.dat Bytes Format Units Label Explanations 1- 9 A9 --- Name Cepheid name 11- 19 F9.3 d MJD Observation date (Modified Julian Day) 21- 25 F5.2 [Sun] [Fe/H] [-0.31/0.55] Metallicity [Fe/H] based on FeI and FeII 27- 30 F4.2 [Sun] e_[Fe/H] [0.01/0.3] Standard deviation on [Fe/H] 32- 34 I3 --- NFe1 [8/118] Number of FeI lines used 36- 37 I2 --- NFe2 [0/14] Number of FeII lines used 39- 43 F5.2 [Sun] [Na/H] [-0.3/1]? Sodium abundance [Na/H] 45- 48 F4.2 [Sun] e_[Na/H] [0/0.4]? Dispersion around the mean on [Na/H] 50 I1 --- NNa [1/2]? Number of NaI lines used 52- 56 F5.2 [Sun] [Al/H] [-0.4/1]? Aluminum abundance [Al/H] 58- 61 F4.2 [Sun] e_[Al/H] [0/0.4]? Dispersion around the mean on [Al/H] 63 I1 --- NAl [1/6]? Number of AlI lines used 65- 69 F5.2 [Sun] [Mg/H] [-0.4/0.6]? Magnesium abundance [Mg/H] 71- 74 F4.2 [Sun] e_[Mg/H] [0/0.6]? Dispersion around the mean on [Mg/H] 76 I1 --- NMg [1]? Number of MgI lines used 78- 82 F5.2 [Sun] [Si/H] [-0.4/0.7]? Silicon abundance [Si/H] 84- 87 F4.2 [Sun] e_[Si/H] [0/0.4]? Dispersion around the mean on [Si/H] 89- 90 I2 --- NSi [1/14]? Number of SiI lines used 92- 96 F5.2 [Sun] [Ca/H] [-0.7/0.5]? Calcium abundance [Ca/H] 98-101 F4.2 [Sun] e_[Ca/H] [0/0.4]? Dispersion around the mean on [Ca/H] 103 I1 --- NCa [1/7]? Number of CaI lines used Byte-by-byte Description of file: table2.dat Bytes Format Units Label Explanations 1- 9 A9 --- Name Cepheid name 11- 16 F6.4 [d] logP [0.36/1.54] Logarithmic pulsation period 18- 22 I5 pc Rgc [4657/14344] Galactocentric distance 24- 26 I3 pc e_Rgc [358/473] Error in the Galactocentric distance 28- 32 F5.2 [Sun] [Fe/H] [-0.31/0.55] Metallicity [Fe/H] based on FeI and FeII 34- 37 F4.2 [Sun] e_[Fe/H] [0.03/0.2]Standard deviation on [Fe/H] 39- 43 F5.2 [Sun] [Na/H] [-0.3/1]? Sodium abundance [Na/H] 45- 48 F4.2 [Sun] e_[Na/H] [0/0.4]? Dispersion around the mean on [Na/H] 50- 54 F5.2 [Sun] [Al/H] [-0.4/1]? Aluminum abundance [Al/H] 56- 59 F4.2 [Sun] e_[Al/H] [0/0.4]? Dispersion around the mean on [Al/H] 61- 65 F5.2 [Sun] [Mg/H] [-0.4/0.6]? Magnesium abundance [Mg/H] 67- 70 F4.2 [Sun] e_[Mg/H] [0/0.6]? Dispersion around the mean on [Mg/H] 72- 76 F5.2 [Sun] [Si/H] [-0.4/0.7]? Silicon abundance [Si/H] 78- 81 F4.2 [Sun] e_[Si/H] [0/0.4]? Dispersion around the mean on [Si/H] 83- 87 F5.2 [Sun] [Ca/H] [-0.7/0.5]? Calcium abundance [Ca/H] 89- 92 F4.2 [Sun] e_[Ca/H] [0/0.4]? Dispersion around the mean on [Ca/H] 94 I1 --- Ns [1/6]? Number of spectra available for each star Byte-by-byte Description of file: table5.dat Bytes Format Units Label Explanations 1 A1 --- n_Name [*] * for observed Cepheids 3- 11 A9 --- Name Cepheid name 13- 17 F5.2 [Sun] [Na/H]o ? Na/H abundance from literature (original) 19- 23 F5.2 [Sun] [Na/H] ? Na/H abundance from literature (rescaled) 25- 28 A4 --- r_[Na/H] ? Reference for the Na literature abundances (1) 30- 34 F5.2 [Sun] [Al/H]o ? Al/H abundance from literature (original) 36- 40 F5.2 [Sun] [Al/H] ? Al/H abundance from literature (rescaled) 42- 45 A4 --- r_[Al/H] ? Reference for the Al literature abundances (1) 47- 51 F5.2 [Sun] [Mg/H]o ? Mg/H abundance from literature (original) 53- 57 F5.2 [Sun] [Mg/H] ? Mg/H abundance from literature (rescaled) 59- 62 A4 --- r_[Mg/H] ? Reference for the Mg literature abundances (1) 64- 68 F5.2 [Sun] [Si/H]o Si/H abundance from literature (original) 70- 74 F5.2 [Sun] [Si/H] Si/H abundance from literature (rescaled) 76- 79 A4 --- r_[Si/H] Reference for the Si literature abundances (1) 81- 85 F5.2 [Sun] [Ca/H]o Ca/H abundance from literature (original) 87- 91 F5.2 [Sun] [Ca/H] Ca/H abundance from literature (rescaled) 93- 96 A4 --- r_[Ca/H] Reference for the Ca literature abundances (1) Note (1): The references are as follows: TS = this study LII = Luck et al., 2011AJ....142...51L, Cat. J/AJ/142/51 LIII = Luck & Lambert,2011AJ....142..136L, Cat. J/AJ/142/136 LEM = Lemasle et al. 2013A&A...558A..31L YON = Yong et al., 2006AJ....131.2256Y Acknowledgements: Ronaldo da Silva, ron.oliveirasilva(at)gmail.com