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J/A+A/487/307       Nearby B-type stars abundances                (Morel+, 2008)

The neon content of nearby B-type stars and its implications for the solar model problem. Morel T., Butler K. <Astron. Astrophys. 487, 307 (2008)> =2008A&A...487..307M
ADC_Keywords: Stars, nearby ; Stars, early-type ; Stars, B-type ; Abundances Keywords: stars: early-type - stars: fundamental parameters - stars: abundances - stars: atmospheres - sun: helioseismology Abstract: The recent downward revision of the solar photospheric abundances now leads to severe inconsistencies between the theoretical predictions for the internal structure of the Sun and the results of helioseismology. There have been claims that the solar neon abundance may be underestimated and that an increase in this poorly-known quantity could alleviate (or even completely solve) this problem. Early-type stars in the solar neighbourhood are well-suited to testing this hypothesis because they are the only stellar objects whose absolute neon abundance can be derived from the direct analysis of photospheric lines. Here we present a fully homogeneous NLTE abundance study of the optical Ne I and Ne II lines in a sample of 18 nearby, early B-type stars, which suggests log[epsilon(Ne)]=7.97±0.07dex (on the scale in which log[epsilon(H)=12)]) for the present-day neon abundance of the local ISM. Chemical evolution models of the Galaxy only predict a very small enrichment of the nearby interstellar gas in neon over the past 4.6Gyr, implying that our estimate should be representative of the Sun at birth. Although higher by about 35% than the new recommended solar abundance, such a value appears insufficient by itself to restore the past agreement between the solar models and the helioseismological constraints. Description: This Table gives the adopted loggf values, EW measurements (in mA) and line-by-line abundances (on the scale in which log[epsilon(H)]=12). A blank indicates that the EW was not reliably measurable, the line was considered blended for the relevant temperature range or yielded a discrepant abundance. The accuracy of the EW measurements is discussed in Sect.3 of the paper. The wing of HeI 4387.9 was taken as pseudo continuum in the case of NeII 4391.99. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file stars.dat 57 18 Star positions (from Simbad) tableb1.dat 43 146 loggf values, EW measurements and line-by-line abundances
See also: J/A+A/412/495 : Equivalent widths for 6 RS CVn systems (Morel+, 2003) J/A+A/423/677 : Chromospherically active stars oxygen abundances (Morel+ 2004) J/A+A/426/1007 : Abundances of 8 single-lined active binaries (Morel+, 2004) J/A+A/457/651 : Abundance of nine beta Cephei stars (Morel+, 2006) Byte-by-byte Description of file: stars.dat
Bytes Format Units Label Explanations
1- 11 A11 --- Name Star name 13- 14 I2 h RAh Simbad Hour of Right Ascension (J2000.0) 16- 17 I2 min RAm Simbad Minute of Right Ascension (J2000.0) 19- 22 F4.1 s RAs Simbad Second of Right Ascension (J2000.0) 24 A1 --- DE- Simbad Sign of the Declination (J2000.0) 25- 26 I2 deg DEd Simbad Degree of Declination (J2000.0) 28- 29 I2 arcmin DEm Simbad Arcminute of Declination (J2000.0) 31- 32 I2 arcsec DEs Simbad Arcsecond of Declination (J2000.0) 36- 40 F5.3 mag Bmag Simbad B band magnitude 42- 46 F5.3 mag Vmag ? Simbad V band magnitude 48- 57 A10 --- SpType Simbad MK spectral type
Byte-by-byte Description of file: tableb1.dat
Bytes Format Units Label Explanations
1- 11 A11 --- Name Star name 13- 18 A6 --- Ion Ion designation 19- 25 F7.2 0.1nm lambda Mean line wavelength 27- 32 F6.3 [-] loggf loggf value 34- 38 F5.1 0.1pm EW ? Equivalent width 40- 43 F4.2 [-] Abund ? Abundance, on log[epsilon(H)]=12 scale
Acknowledgements: Thierry Morel, morel(at)astro.ulg.ac.be
(End) Patricia Vannier [CDS] 05-Jun-2008
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

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