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 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:
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FileName Lrecl Records Explanations
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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
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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
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Bytes Format Units Label Explanations
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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
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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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
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Acknowledgements:
Thierry Morel, morel(at)astro.ulg.ac.be
(End) Patricia Vannier [CDS] 05-Jun-2008