J/A+A/608/A46 Constraining cosmic scatter (Reggiani+, 2017)
Constraining cosmic scatter in the Galactic halo through a differential analysis
of metal-poor stars.
Reggiani H., Melendez J., Kobayashi C., Karakas A., Placco V.
<Astron. Astrophys. 608, A46 (2017)>
=2017A&A...608A..46R 2017A&A...608A..46R (SIMBAD/NED BibCode)
ADC_Keywords: Stars, population II ; Abundances, [Fe/H] ; Spectroscopy
Keywords: stars: abundances - stars: evolution - stars: Population II -
Galaxy: abundances - Galaxy: evolution - Galaxy: halo
Abstract:
We present the stellar parameters, abundances, associated errors and
the linelist of a set of 23 metal-poor and very metal-poor halo stars.
Stellar parameters and chemical abundances were derived in a
line-by-line differential analysis from equivalent widths of UVES/VLT
spectra. The differential analysis provided us unprecedented small
data scatter and errors. Our sample, along with data from different
authors in different metallicity ranges, allowed us to do an extensive
comparison of the chemical abundances with the predictions of a Galaxy
chemical evolution model.
Description:
The observational data were obtained with the UVES spectrograph at the
8.2m VLT telescope, during 2015A (project 095.D-0504(A)). All the
spectra were taken with the same instrumental configuration, which
guarantees similar spectra quality and improves the precision in a
line-by-line differential analysis. The blue side of the spectra has
an effective range from 330nm to 450nm, and the red side of the
spectra has a range of 480nm-680nm. We used a 0.8" slit on both arms
of the spectrograph, with a final resolution of R=50000 per pixel in
both the blue arm and red arms. The average S/N of the sample is:
S/N=130 at 4000Å and S/N=250 at 6000Å. All equivalent widths
were measured manually using the splot task in IRAF.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea.dat 309 23 Stellar parameters and abundances (tables A1-A6)
linelist.dat 30 823 Linelist
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Byte-by-byte Description of file: tablea.dat
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Bytes Format Units Label Explanations
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1- 24 A24 --- Star Identification of the star
26- 29 I4 K Teff Effective temperature
31- 32 I2 K e_Teff Error in effective temperature
34- 37 F4.2 [cm/s2] logg Logarithmic surface gravity
39- 42 F4.2 [cm/s2] e_logg Error in surface gravity
44- 47 F4.2 km/s vt Micro-turbulence velocity
49- 52 F4.2 km/s e_vt Error in micro-turbulence velocity
54- 59 F6.3 --- [Fe/H] Metallicity
61- 65 F5.3 --- e_[Fe/H] Error in metallicity
67- 71 F5.3 --- [Mg/Fe] Magnesium-to-iron ratio
73- 77 F5.3 --- e_[Mg/Fe] Error in magnesium-to-iron ratio
79- 83 F5.3 --- [Si/Fe] Silicon-to-iron ratio
85- 89 F5.3 --- e_[Si/Fe] Error in silicon-to-iron ratio
91- 95 F5.3 --- [Ca/Fe] Calcium-to-iron ratio
97-101 F5.3 --- e_[Ca/Fe] Error in calcium-to-iron ratio
103-107 F5.3 --- [Ti/Fe] Titanium-to-iron ratio
109-113 F5.3 --- e_[Ti/Fe] Error in titanium-to-iron ratio
115-120 F6.3 --- [Na/Fe]N NLTE sodium-to-iron ratio
122-126 F5.3 --- e_[Na/Fe]N Error in sodium-to-iron ratio
128-133 F6.3 --- [Al/Fe]N NLTE aluminium-to-iron ratio
135-139 F5.3 --- e_[Al/Fe]N Error in aluminium-to-iron ratio
141-145 F5.3 --- [Sc/Fe] Scandium-to-iron ratio
147-151 F5.3 --- e_[Sc/Fe] Error in scandium-to-iron ratio
153-158 F6.3 --- [V/Fe] Vanadium-to-iron ratio
160-164 F5.3 --- e_[V/Fe] Error in vanadium-to-iron ratio
166-171 F6.3 --- [CrI/Fe] ChromiumI-to-iron ratio
173-177 F5.3 --- e_[CrI/Fe] Error in chromiumI-to-iron ratio
179-183 F5.3 --- [CrII/Fe] ChromiumII-to-iron ratio
185-189 F5.3 --- e_[CrII/Fe] Error in chromiumII-to-iron ratio
191-196 F6.3 --- [Mn/Fe] Manganese-to-iron ratio
198-202 F5.3 --- e_[Mn/Fe] Error in manganese-to-iron ratio
204-209 F6.3 --- [Co/Fe] Cobalt-to-iron ratio
211-215 F5.3 --- e_[Co/Fe] Error in cobalt-to-iron ratio
217-222 F6.3 --- [Ni/Fe] Nickel-to-iron ratio
224-228 F5.3 --- e_[Ni/Fe] Error in nickel-to-iron ratio
230-234 F5.3 --- [Zn/Fe] Zinc-to-iron ratio
236-240 F5.3 --- e_[Zn/Fe] Error in zinc-to-iron ratio
242-247 F6.3 --- [Sr/Fe] Strontium-to-iron ratio
249-253 F5.3 --- e_[Sr/Fe] Error in strontium-to-iron ratio
255-260 F6.3 --- [Y/Fe] Yttrium-to-iron ratio
262-266 F5.3 --- e_[Y/Fe] Error in yttrium-to-iron ratio
268-272 F5.3 --- [Zr/Fe] Zirconium-to-iron ratio
274-278 F5.3 --- e_[Zr/Fe] Error in zirconium-to-iron ratio
280-285 F6.3 --- [Ba/Fe] Barium-to-iron ratio
287-291 F5.3 --- e_[Ba/Fe] Error in barium-to-iron ratio
293-297 F5.3 --- A(Li) ? Li abundance (1)
299-303 F5.3 --- e_A(Li) ? Error in Li abundance
305-309 F5.3 Msun Mass ? Mass (1)
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Note (1): No value for the two blue straggler stars.
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Byte-by-byte Description of file: linelist.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 --- lambda Wavelength of the line
13- 16 F4.1 --- Species Species and ionization stage
21- 24 F4.2 --- EP Excitation potential of the line
26- 30 F5.2 --- loggf log gf of the line
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Acknowledgements:
Henrique Reggiani, hreggiani(at)gmail.com
(End) H. Reggiani [Max Planck, Germany], P. Vannier [CDS] 13-Sep-2017