J/MNRAS/447/2404 Equivalent width of 21 RR Lyrae stars (Pancino+, 2015) ================================================================================ Chemical abundances of solar neighbourhood RR Lyrae stars. Pancino E., Britavskiy N., Romano D., Cacciari C., Mucciarelli A., Clementini G. =2015MNRAS.447.2404P ================================================================================ ADC_Keywords: Stars, nearby ; Stars, variable ; Spectroscopy ; Equivalent widths Keywords: stars: abundances - stars: variables: Cepheids - stars: variables: general - stars: variables: RR Lyrae Abstract: We have analysed a sample of 18 RR Lyrae stars (17 fundamental-mode - RRab - and one first overtone - RRc) and three Population II Cepheids (two BL Her stars and one W Vir star), for which high-resolution (R>=30000), high signal-to-noise (S/N>=30) spectra were obtained with either SARG at the Telescopio Nazionale Galileo (La Palma, Spain) or UVES at the ESO Very Large Telescope (Paranal, Chile). Archival data were also analyzed for a few stars, sampling >~3 phases for each star. We obtained atmospheric parameters (T_eff_, logg, v_t_, and [M/H]) and abundances of several iron-peak and {alpha}-elements (Fe, Cr, Ni, Mg, Ca, Si, and Ti) for different pulsational phases, obtaining <[{alpha}/Fe]>=+0.31+/-0.19dex over the entire sample covering -2.2<[Fe/H]<-1.1dex. We find that silicon is indeed extremely sensitive to the phase, as reported by previous authors, and cannot be reliably determined. Apart from this, metallicities and abundance ratios are consistently determined, regardless of the phase, within 0.10-0.15 dex, although caution should be used in the range 0<~{phi}<~0.15. Our results agree with literature determinations for both variable and non-variable field stars, obtained with very different methods, including low and high-resolution spectroscopy. W Vir and BL Her stars, at least in the sampled phases, appear indistinguishable from RRab from the spectroscopic analysis point of view. Our large sample, covering all pulsation phases, confirms that chemical abundances can be obtained for RR Lyrae with the classical EW-based technique and static model atmospheres, even rather close to the shock phases. Description: Equivalent widths and atomic data of the absorption lines used in the abundance analysis, for each separate exposure at different phases. Observations of 15 RR Lyrae stars (DR And, X Ari, TW Boo, RZ Cam, RX Cet, U Com, RV CrB, SW CVn, UZ CVn, AE Dra, SZ Gem, VX Her, DH Hya, TU UMa, and RV UMa) and one BL Her star (UY Eri) were carried out with SARG@TNG, operated on the island of La Palma, Spain, during two separate runs in 2009 March and between September and November. Eight stars (SW Aqr, TW Cap, DH Hya, V Ind, SS Leo, V716 Oph, BK Tuc, and UV Vir) were observed with UVES@VLT, between 2009 April and August in service mode. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 106 21 Basic information for the programme stars table2.dat 45 59 Observing logs table4.dat 66 8546 Equivalent wodths and atomic data for individual program stars spectra -------------------------------------------------------------------------------- Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 8 A8 --- Star Star name 9 A1 --- n_Star [*] Note on Star (2) 11- 12 I2 h RAh Right ascension (J2000) (1) 14- 15 I2 min RAm Right ascension (J2000) (1) 17- 21 F5.2 s RAs Right ascension (J2000) (1) 23 A1 --- DE- Declination (J2000) (1) 24- 25 I2 deg DEd Declination (J2000) (1) 27- 28 I2 arcmin DEm Declination (J2000) (1) 30- 33 F4.1 arcsec DEs Declination (J2000) 35- 38 A4 --- Type Variable type (1) 40- 46 A7 --- Type2 Alternative variable type (1) 48- 52 F5.2 mag Vmin [8.9/12.4] Minimum value of V magnitude (1) 53 A1 --- --- [-] 54- 58 F5.2 mag Vmax [9.9/13.4] Maximum value of V magnitude (1) 60- 71 F12.6 d T0 Epoch of maximum light (JD-2400000) (3) 73- 83 F11.8 d Per Period 85- 88 F4.2 mag AV Absorption in V band 89 A1 --- n_AV [)] Origin of AV (4) 91- 95 F5.2 [Sun] [Fe/H]1 [-2.5/-0.8]?=- Metallicity from Kinemuchi et al. 2006 (J/AJ/132/1202) (5) 97-100 F4.2 [Sun] e_[Fe/H]1 ? rms uncertainty on [Fe/H]K06 102-106 F5.2 [Sun] [Fe/H]2 [-2.5/-0.8] Metallicity from Beers et al. (2000, Cat. J/AJ/119/2866) (5) -------------------------------------------------------------------------------- Note (1): Coordinates, type of variability, rough magnitude ranges and adopted periods are from the General Catalogue of Variable Stars (GCVS; Samus et al. 2010, Cat. B/gcvs), except for X Ari, TW Boo, RX Cet, and VX Her, that are known to have a variable period (Le Borgne et al. 2007A&A...476..307L, Cat. J/A+A/476/307, see also text). Note (2): * indicates stars that do not have a clear classification, but for our computations we used the type in Type. Note (3): Epochs of maximum light have been derived by us from ROTSE light curves, except for X Ari, TW Boo, RX Cet, and VX Her, where a parabolic fit was used, based on data from Le Borgne et al. (2007, Cat. J/A+A/476/307,). For a few stars with no ROTSE data, epochs are taken from the GCVS, and for SS Leo from Maintz (2005A&A...442..381M, Cat. J/A+A/442/381). V amplitudes are from Kinemuchi et al. (2006AJ....132.1202K, Cat. J/AJ/132/1202); Note (4): ) indicates that AV are either derived from ROTSE light curves (TW Cap, U Com, UY Eri, and V716 Oph), or taken from the ASAS-3 catalogue (V Ind, VW Scl, BK Tuc; Pojmanski, 1997AcA....47..467P); Note (5): typical errors are on the order 0.1-0.2dex. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 8 A8 --- Star Star name 10- 14 A5 --- Inst Instrument 17- 18 I2 --- Exp [1/10] Exposure number for star+instrument 19 A1 --- n_Exp [*] * indicates archival spectra 21- 31 F11.5 d ObsDate Observation date (HJD-2400000) 33- 36 F4.2 --- Phase [0/1] Phase 38- 41 F4.1 min texp [3/60] Exposure time 43- 45 I3 --- S/N [20/160] Signal-to-noise ratio (at 600nm) -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 8 A8 --- Star Star name 10- 15 A6 --- Inst Instrument name 16 I1 --- Exp [0/9] Exposure number for star+instrument 17- 26 F10.3 0.1nm lambda [4620/7946] Wavelength {lambda} in Angstroms 30- 34 A5 --- Ion Element name and ionization stage 35- 42 F8.2 0.1pm EW [6/111] Equivalent width in milliAngstroms 43- 49 F7.2 0.1pm e_EW Error on EW in milliAngstroms 50- 58 F9.3 [-] loggf Logarithm of the oscillator strength 59- 66 F8.3 eV EP Excitation potential {chi} -------------------------------------------------------------------------------- Acknowledgements: Elena Pancino, elena.pancino(at)oabo.inaf.it ================================================================================ (End) Elena Pancino [INAF-OABo, Italy], Patricia Vannier [CDS] 26-Feb-2015