J/ApJ/819/103 Abundances of two very metal-poor stars (Afsar+, 2016)
The chemical compositions of very metal-poor stars HD 122563 and HD 140283:
a view from the infrared.
Afsar M., Sneden C., Frebel A., Kim H., Mace G.N., Kaplan K.F., Lee H.-I.,
Oh H., Oh J.S., Pak S., Park C., Pavel M.D., Yuk I.-S., Jaffe D.T.
<Astrophys. J., 819, 103 (2016)>
=2016ApJ...819..103A 2016ApJ...819..103A (SIMBAD/NED BibCode)
ADC_Keywords: Abundances ; Equivalent widths ; Spectra, infrared ; Stars, halo
Keywords: instrumentation: spectrographs; stars: abundances; stars: atmosphere;
stars: individual: (HD 122563, HD 140283); stars: Population II
Abstract:
From high resolution (R~=45000), high signal-to-noise ratio (S/N>400)
spectra gathered with the Immersion Grating Infrared Spectrograph
(IGRINS) in the H and K photometric bands, we have derived elemental
abundances of two bright, well-known metal-poor halo stars: the red
giant HD 122563 and the subgiant HD 140283. Since these stars have
metallicities approaching [Fe/H]=-3, their absorption features are
generally very weak. Neutral-species lines of Mg, Si, S and Ca are
detectable, as well as those of the light odd-Z elements Na and Al.
The derived IR-based abundances agree with those obtained from
optical-wavelength spectra. For Mg and Si the abundances from the
infrared transitions are improvements to those derived from shorter
wavelength data. Many useful OH and CO lines can be detected in the
IGRINS HD 122563 spectrum, from which derived O and C abundances are
consistent to those obtained from the traditional [OI] and CH
features. IGRINS high resolutions H- and K-band spectroscopy offers
promising ways to determine more reliable abundances for additional
metal-poor stars whose optical features are either not detectable, or
too weak, or are based on lines with analytical difficulties.
Description:
We obtained high-resolution (R∼45000), high S/N (S/N>400, per
resolution element) spectra of HD 122563 and HD 140283 with the H and
K band Immersion Grating Infrared Spectrograph (IGRINS) during an
instrument commissioning run on the night of 2014 May 23 at the
McDonald Observatory with the 2.7m Smith Telescope.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 59 2 Program star parameters and observations
table2.dat 67 232 Parameters of Fe and Ti lines
table3.dat 67 169 Parameters of other species lines
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See also:
J/A+A/584/A86 : Abundance analysis of HD 140283 (Siqueira-Mello+, 2015)
J/A+A/577/A18 : Reduced CRIRES spectra around S multiplet 3 (Kacharov+, 2015)
J/A+A/575/A26 : The Population II star HD 140283 data (Creevey+, 2015)
J/ApJS/215/23 : FeI branching fractions (Den Hartog+, 2014)
J/ApJS/214/26 : Line lists for CN isotopes transitions (Sneden+, 2014)
J/MNRAS/441/3127 : FeI oscillator strengths for Gaia-ESO (Ruffoni+, 2014)
J/AJ/147/136 : Stars of very low metal abundance. VI. (Roederer+, 2014)
J/ApJS/208/27 : Sun and HD 84937 TiII log(gf) and abundances (Wood+, 2013)
J/ApJ/762/26 : Most metal-poor stars. II. Galactic halo stars (Yong+, 2013)
J/A+A/548/A42 : HD 140283 average spectrum (370-1040nm) (Siqueira Mello+ 2012)
J/AJ/141/175 : Abundances in M15 RGB/RHB stars (Sobeck+, 2011)
J/ApJ/742/54 : CASH project II. 14 extremely metal-poor stars (Hollek+, 2011)
J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)
J/A+A/415/993 : FeII, ZNI and SI abundances on halo stars (Nissen+, 2004)
J/ApJ/530/783 : The r-process enriched giant HD 115444 (Westin+, 2000)
J/ApJS/95/535 : Infrared CO line list for X 1Σ+ state (Goorvitch, 1994)
J/AJ/90/2089 : Stars of very low metal abundance. I (Beers+, 1985)
http://www.sdss3.org/surveys/apogee.php : APOGEE home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Star Star Name
11- 12 I2 h RAh SIMBAD Hour of Right Ascension (J2000) (1)
14- 15 I2 min RAm Minute of Right Ascension (J2000)
17- 22 F6.3 s RAs Second of Right Ascension (J2000)
23 A1 --- DE- SIMBAD Sign of the Declination (J2000) (1)
24- 25 I2 deg DEd SIMBAD Degree of Declination (J2000) (1)
27- 28 I2 arcmin DEm Arcminute of Declination (J2000)
30- 34 F5.2 arcsec DEs Arcsecond of Declination (J2000)
36- 39 F4.2 mag Vmag [6.1/7.3] SIMBAD V magnitude (1)
41- 44 F4.2 mag Hmag [3.7/5.7] SIMBAD H magnitude (1)
46- 49 F4.2 mag Kmag [3.7/5.6] SIMBAD K magnitude (1)
51- 53 I3 s Exp [960] Total Exposure time
56 A1 --- l_S/N Upper limit flag on S/N
57- 59 I3 --- S/N [400] Signal to Noise
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Note (1): Positions and magnitudes taken from the SIMBAD database,
http://simbad.u-strasbg.fr/simbad/
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 11 F11.2 0.1nm lambda [4394/7946] Wavelength in Angstroms, in air units
12- 18 A7 --- Ion Species identification (Fe I, Fe II, Ti I or Ti II)
19- 27 F9.3 eV chi [0/4.7] Lower excitation level
28- 35 F8.2 [-] log(gf) [-5.5/0.6] Log of the oscillator strength
36- 43 F8.1 0.1pm EW-1 [1/168] HD 122563 equivalent width, milli-Angstroms
44- 51 F8.1 0.1pm EW-2 [1/109]? HD 140283 equivalent width (mÅ)
52- 59 F8.2 --- [X/Fe]1 [-3.3/0.4] Relative abundance, HD 122563 (G1)
60- 67 F8.2 --- [X/Fe]2 [-2.9/0.5]? Relative abundance, HD 140283 (G1)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 11 F11.2 0.1nm lambda [3905.5/23447.8] Wavelength in Angstroms,
in air units
12- 18 A7 --- Ion Species identification
19- 27 F9.3 eV chi [0/8.1] Lower excitation level
30- 35 F6.2 --- log(gf) [-10.2/4.9] Oscillator strength
39- 43 F5.1 0.1pm EW-1 [1.5/237]? Equivalent width, HD 122563 (mÅ)
45 A1 --- f_EW-1 [s] s: spectrum synthesis measurement
47- 51 F5.1 0.1pm EW-2 [2.8/169.8]? Equivalent width, HD 140283 (mÅ)
53 A1 --- f_EW-2 [s] s: spectrum synthesis measurement
55- 59 F5.2 --- [X/Fe]1 [-0.7/1.1]? Relative abundance, HD 122563 (G1)
63- 67 F5.2 --- [X/Fe]2 [-1/0.8]? Relative abundance, HD 140283 (G1)
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Global note:
Note (G1): Solar abundances are from Asplund et al. (2009ARA&A..47..481A 2009ARA&A..47..481A);
for Fe I and Fe II, the abundances are expressed as [Fe/H].
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 23-May-2016