J/ApJ/795/23 Line list for stellar chemical abundances (Bedell+, 2014)
Stellar chemical abundances: in pursuit of the highest achievable precision.
Bedell M., Melendez J., Bean J.L., Ramirez I., Leite P., Asplund M.
<Astrophys. J., 795, 23 (2014)>
=2014ApJ...795...23B 2014ApJ...795...23B (SIMBAD/NED BibCode)
ADC_Keywords: Minor planets ; Milky Way ; Equivalent widths
Keywords: stars: abundances - stars: fundamental parameters -
techniques: spectroscopic
Abstract:
The achievable level of precision on photospheric abundances of stars
is a major limiting factor on investigations of exoplanet host star
characteristics, the chemical histories of star clusters, and the
evolution of the Milky Way and other galaxies. While model-induced
errors can be minimized through the differential analysis of
spectrally similar stars, the maximum achievable precision of this
technique has been debated. As a test, we derive differential
abundances of 19 elements from high-quality asteroid-reflected solar
spectra taken using a variety of instruments and conditions. We treat
the solar spectra as being from unknown stars and use the resulting
differential abundances, which are expected to be zero, as a
diagnostic of the error in our measurements. Our results indicate that
the relative resolution of the target and reference spectra is a major
consideration, with use of different instruments to obtain the two
spectra leading to errors up to 0.04 dex. Use of the same instrument
at different epochs for the two spectra has a much smaller effect
(∼0.007 dex). The asteroid used to obtain the solar standard also has
a negligible effect (∼0.006 dex). Assuming that systematic errors from
the stellar model atmospheres have been minimized, as in the case of
solar twins, we confirm that differential chemical abundances can be
obtained at sub-0.01 dex precision with due care in the observations,
data reduction, and abundance analysis.
Description:
The five solar spectra used in this analysis were obtained with very
high resolution and signal-to-noise ratios (S/Ns) characteristic of
data used in past stellar abundance analyses. Two spectra were taken
with the Echelle SpectroPolarimetric Device for the Observation of
Stars (ESPaDOnS) instrument (Donati 2003, Solar Polarization (ASP
Conf. Ser. 307), ed. J. Trujillo-Bueno & J. Sanchez Almeida (San
Francisco, CA: ASP), 41) at the 3.6 m Canada-France-Hawaii
Telescope on the night of 2013 March 4. The asteroids Ceres and Vesta
were each observed in "star only" mode at a spectral resolving power
R=81000. The remaining three solar spectra were taken with the
Magellan Inamori Kyocera Echelle (MIKE) spectrograph (Bernstein et al.
2003SPIE.4841.1694B 2003SPIE.4841.1694B) at the 6.5 m Magellan Clay telescope. The
asteroid Vesta was observed twice and Iris was observed once during
three separate observing runs spanning January to September of 2011.
All observations were carried out in MIKE's standard setup with the
0.35 arcsec width slit, giving a spectral resolving power of
R=83000 on the blue CCD and 65000 on the red CCD.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 53 307 Line list
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See also:
J/A+A/544/A125 : Solar lines from Ceres spectra (Molaro+, 2012)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 0.1nm Wave Wavelength in Angstroms
9- 12 F4.1 --- Species Species identifier (1)
14- 17 F4.2 eV ExPot Excitation potential
19- 23 F5.2 [-] log(gf) Log of the oscillator strength
25- 29 F5.1 0.1pm Vesta1 ? ESPaDOnS equivalent width of Vesta (2)
31- 35 F5.1 0.1pm Ceres ? ESPaDOnS equivalent width of Ceres (2)
37- 41 F5.1 0.1pm Vesta2 ? MIKE June 24, 2011 equivalent width
of Vesta (2)
43- 47 F5.1 0.1pm Vesta3 ? MIKE Sept 09, 2011 equivalent width
of Vesta (2)
49- 53 F5.1 0.1pm Iris ? MIKE equivalent width of Iris (2)
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Note (1): Where the number before the decimal is the element number and the
number after the decimal is the ionization state, e.g. 6.0=C I.
Note (2): In units of milli-Angstroms. Observation details available in Table 1.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 17-May-2017