Access to Astronomical Catalogues

← Click to display the menu
J/A+A/425/671       Equivalent widths of 10 metal-poor halo stars   (Bai+, 2004)

Chemical abundances of 10 metal-poor halo stars. Bai G.S., Zhao G., Chen Y.Q., Shi J.R., Klochkova V.G., Panchuk V.E., Qiu H.M., Zhang H.W. <Astron. Astrophys. 425, 671 (2004)> =2004A&A...425..671B
ADC_Keywords: Stars, population II ; Stars, metal-deficient ; Equivalent widths Keywords: stars: abundances - stars: fundamental parameters - Galaxy: abundances - Galaxy: halo Abstract: We presented the observed information of ten metal-poor halo stars with the metallicity range -2.3<[Fe/H]< -1.4 and derived their stellar parameters, acquired some elemental abundances relative to iron and discussed the relation between the abundance ratio and the metallicity. The stars were observed using the 6m telescope of the Special Astrophysical Observatory with the ECHELLE spectrometer PFES equipped with the CCD (1040x1160 pixels, pixel size 16x16µm). The spectral wavelength coverage is of 430-798nm with the resolving power of 15000 and the signal-to-noise ratio is about 200. It was found that oxygen abundances are nearly constant at a level of 0.6dex for our metal-poor halo stars when the non-LTE correction is considered. The alpha-elements (Mg, Si, Ca and Ti) are overabundant relative to Fe and decrease with increasing metallicity. We also obtained a significant underabundant non-LTE [Na/Fe] ratio from NaI D lines which have large deviation from LTE assumption. Scandium is marginally overabundant with respect to iron and tends to decrease with increasing metallicity like the alpha-elements. Nearly solar value of [Cr/Fe] ratio and underabundant [Mn/Fe] ratio are obtained. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file stars.dat 64 10 Star positions and magnitudes (from Simbad) ewline.dat 111 197 Atomic line data and equivalent widths
See also: J/A+AS/141/491 : Chemical composition of halo and disk stars (Nissen+, 2000) Byte-by-byte Description of file: stars.dat
Bytes Format Units Label Explanations
1- 10 A10 --- Name Star name 15- 16 I2 h RAh Right ascension (J2000.0) 18- 19 I2 min RAm Right ascension (J2000.0) 21- 24 F4.1 s RAs Right ascension (J2000.0) 26 A1 --- DE- Declination sign (J2000.0) 27- 28 I2 deg DEd Declination (J2000.0) 30- 31 I2 arcmin DEm Declination (J2000.0) 33- 34 I2 arcsec DEs Declination (J2000.0) 38- 42 F5.2 mag Bmag ? B magnitude 44- 48 F5.2 mag Vmag ? V magnitude 50- 53 A4 --- SpType Spectral type 55- 64 A10 "Y-M-D" ObsDate Observation Date
Byte-by-byte Description of file: ewline.dat
Bytes Format Units Label Explanations
1- 8 F8.3 0.1nm Lambda Wavelength 11- 14 A4 --- Ion Specie name and ionization 16- 19 F4.2 eV EP Excitation potential 22- 26 F5.2 --- loggf log of Oscillator Strength 29- 31 F3.1 --- f6 Enhancement factor 34- 39 F6.1 0.1pm EW1 ? Equivalent width for HD 108177 42- 47 F6.1 0.1pm EW2 ? Equivalent width for HD 149414 50- 55 F6.1 0.1pm EW3 ? Equivalent width for BD+02 3375 58- 63 F6.1 0.1pm EW4 ? Equivalent width for BD+20 3603 66- 71 F6.1 0.1pm EW5 ? Equivalent width for BD+26 2606 74- 79 F6.1 0.1pm EW6 ? Equivalent width for BD+28 2137 82- 87 F6.1 0.1pm EW7 ? Equivalent width for BD+29 2091 90- 95 F6.1 0.1pm EW8 ? Equivalent width for BD+34 2476 98-103 F6.1 0.1pm EW9 ? Equivalent width for BD+42 2667 106-111 F6.1 0.1pm EW10 ? Equivalent width for BD+51 1696
Acknowledgements: Chen Yu Qin, cyq(at)ns.bao.ac.cn
(End) Patricia Vannier [CDS] 17-Sep-2004
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© UDS/CNRS

Contact