J/A+A/493/601 Lithium abundances of halo dwarfs (Hosford+, 2009)
Lithium abundances of halo dwarfs based on excitation temperature.
I. Local thermodynamic equilibrium.
Hosford A., Ryan S.G., Garcia Perez A.E., Norris J.E., Olive K.A.
<Astron. Astrophys. 493, 601 (2009)>
=2009A&A...493..601H 2009A&A...493..601H
ADC_Keywords: Stars, dwarfs ; Abundances
Keywords: Galaxy: halo - cosmology: early Universe -
nuclear reactions, nucleosynthesis, abundances - stars: abundances
Abstract:
The discovery of the Spite plateau in the abundances of 7Li^ for
metal-poor stars led to the determination of an observationally
deduced primordial lithium abundance. However, after the success of
the Wilkinson Microwave Anisotropy Probe (WMAP) in determining the
baryon density, ΩBh2, there was a discrepancy between
observationally determined and theoretically determined abundances in
the case of 7Li. One of the most important uncertain
factors in the calculation of the stellar 7Li abundance is
the effective temperature, Teff.
We use sixteen metal-poor halo dwarfs to calculate new Teff values
using the excitation energy method. With this temperature scale we
then calculate new Li abundances for this group of stars in an attempt
to resolve the 7Li discrepancy.
Description:
Using high signal-to-noise (S/N∼100) spectra of 16 metal-poor halo
dwarfs, obtained with the UCLES spectrograph on the AAT, measurements
of equivalent widths from a set of unblended FeI lines are made.
Table contains the wavelength, first column, of each line measured in
the spectra of the program stars. Along with this there are the
log(gf) values, the references for the log(gf) values and the
excitation energy values for each spectral line, columns 2, 3 and 4
respectively. Following this we present the measured equivalent widths
from the program stars, remaining columns.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
stars.dat 52 18 Star list
table.dat 49 4338 Equivalent widths (tables 6-8 of the paper)
--------------------------------------------------------------------------------
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)
35- 39 F5.2 mag Bmag Simbad B band magnitude
41- 45 F5.2 mag Vmag Simbad V band magnitude
47- 52 A6 --- SpType Simbad MK spectral type
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Name Star name
13- 16 A4 --- Ion Ion (FeI or FeII)
18- 24 F7.2 0.1nm Lambda Wavelength
26- 30 F5.2 --- loggf Oscillator strength
32- 38 A7 --- r_loggf Reference for loggf (1)
40- 43 F4.2 eV chi Excitation energy value
45- 49 F5.1 --- EW ?=- Equivalent width
--------------------------------------------------------------------------------
Note (1): References as follows:
1 = Bard & Kock (1994A&A...282.1014B 1994A&A...282.1014B)
2 = Bard et al. (1991A&A...248..315B 1991A&A...248..315B)
3 = Fuhr et al. (1988, Cat. VI/72)
4 = O'Brian et al. (1991JOSAB...8.1185O 1991JOSAB...8.1185O)
5 = Oxford FeI consortium
6 = Thevenin et al (1989A&AS...77..137T 1989A&AS...77..137T)
7 = Hannaford et al (1992A&A...259..301H 1992A&A...259..301H)
8 = Heise & Kock (1990A&A...230..244H 1990A&A...230..244H)
9 = Kroll & Kock (1987A&AS...67..225K 1987A&AS...67..225K)
10 = Moity (1983A&AS...52...37M 1983A&AS...52...37M)
11 = Schnabel, Kock & Holweger (1999A&A...342..610S 1999A&A...342..610S)
--------------------------------------------------------------------------------
Acknowledgements:
A. Hosford, a.hosford(at)herts.ac.uk
(End) Patricia Vannier [CDS] 06-Nov-2008