J/A+A/591/A34 Chemical abundances of zeta Reticuli (Adibekyan+, 2016)
zeta2 Reticuli, its debris disk, and its lonely stellar companion
zeta 1 Ret. Different Tc trends for different spectra.
Adibekyan V., Delgado-Mena E., Figueira P., Sousa S.G., Santos N.C.,
Faria J.P., Gonzalez Hernandez J.I., Israelian G., Harutyunyan G.,
Suarez-Andres L., Hakobyan A.A.
<Astron. Astrophys. 591, A34 (2016)>
=2016A&A...591A..34A 2016A&A...591A..34A (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Abundances
Keywords: stars: abundances - planetary systems -
stars: individual: Zet1 Ret (HD 20766) - techniques: spectroscopic -
stars: individual: Zet2 Ret (HD 20807) - binaries: general
Abstract:
Several studies have reported a correlation between the chemical
abundances of stars and condensation temperature (known as Tc trend).
Very recently, a strong Tc trend was reported for the zeta Reticuli
binary system, which consists of two solar analogs. The observed trend
in zeta2 Ret relative to its companion was explained by the presence
of a debris disk around zeta2 Ret. Our goal is to re-evaluate the
presence and variability of the Tc trend in the zeta Reticuli system
and to understand the impact of the presence of the debris disk on a
star. We used very high-quality spectra of the two stars retrieved
from the HARPS archive to derive very precise stellar parameters and
chemical abundances. We derived the stellar parameters with the
classical (nondifferential) method, while we applied a differential
line-by-line analysis to achieve the highest possible precision in
abundances, which are fundamental to explore for very tiny differences
in the abundances between the stars. We confirm that the abundance
difference between zeta2 Ret and zeta1 Ret shows a significant
(∼2σ) correlation with Tc. However, we also find that the Tc
trends depend on the individual spectrum used (even if always of very
high quality). In particular, we find significant but varying
differences in the abundances of the same star from different
individual high-quality spectra. Our results for the zeta Reticuli
system show, for example, that nonphysical factors, such as the
quality of spectra employed and errors that are not accounted for, can
be at the root of the Tc trends for the case of individual spectra.
Description:
The file table1.dat lists stellar parameters, S/N, and observation
dates of zeta1 Ret and zeta2 Ret derived from individual and
combined spectra
The file ew.dat lists the equivalent widths (EW) of all the spectral
lines.
The file s_lines.dat lists the lines that were used in this study.
The file abund.dat lists the derived abundances of the elements for
each star and spectra.
Objects:
--------------------------------------------------
RA (2000) DE Designation(s)
--------------------------------------------------
03 17 46.16 -62 34 31.2 zeta1 Ret = HD 20766
03 18 12.82 -62 30 22.9 zeta2 Ret = HD 20807
--------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 82 11 Stellar parameters, S/N, and observation dates of
zeta1 Ret and zeta2 Ret derived from
individual and combined spectra
ew.dat 31 1997 EWs of the spectral lines used to derive
abund.dat 242 24 Abundances for each star and element
s_lines.dat 33 627 Line list of S (6046.0, 6052.5, 6743.5, and 6757.1)
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See also:
J/A+A/588/A81 : Line list and abundances of the binary zet2 Ret (Saffe+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Star Star's identifier/spectrum
14- 17 I4 K Teff Effective temperature
19- 20 I2 K e_Teff rms uncertainty on Teff
22- 25 F4.2 [cm/s2] logg Surface gravity
27- 30 F4.2 [cm/s2] e_logg rms uncertainty on logg
32- 37 F6.3 [-] [Fe/H] Metallicity
39- 43 F5.3 [-] e_[Fe/H] rms uncertainty on [Fe/H]
45- 48 F4.2 km/s Vtur Turbulent velocity
50- 53 F4.2 km/s e_Vtur rms uncertainty on Vtur
55- 58 I4 --- S/N Signal-to-noise ratio
60- 82 A23 --- Obs.date Observation date (YYYY-MM-DDThh:mm:ss.sss)
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Byte-by-byte Description of file: ew.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 ----- Star Star's identifier/spectrum
14- 20 F7.2 0.1nm lambda Central wavelength
22- 25 F4.1 --- Elem Element number
27- 31 F5.1 0.1pm EW Equivalent width of the line
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Byte-by-byte Description of file: abund.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Elem Element
10- 15 F6.3 [Sun] [X/H]1 Abundance (zet1ret_comb - Sun)
17- 21 F5.3 [Sun] stot1 Total error (zet1ret_comb - Sun)
23- 28 F6.3 [Sun] [X/H]2 Abundance (zet1ret_s16 - Sun)
30- 34 F5.3 [Sun] stot2 Total error (zet1ret_s16 - Sun)
36- 41 F6.3 [Sun] [X/H]3 Abundance (zet1ret_c - Sun)
43- 47 F5.3 [Sun] stot3 Total error (zet1ret_c - Sun)
49- 54 F6.3 [Sun] [X/H]4 Abundance (zet1ret_b - Sun)
56- 60 F5.3 [Sun] stot4 Total error (zet1ret_b - Sun)
62- 67 F6.3 [Sun] [X/H]5 Abundance (zet1ret_a - Sun)
69- 73 F5.3 [Sun] stot5 Total error (zet1ret_a - Sun)
75- 80 F6.3 [Sun] [X/H]6 Abundance (zet2ret_comb - Sun)
82- 86 F5.3 [Sun] stot6 Total error (zet2ret_comb - Sun)
88- 93 F6.3 [Sun] [X/H]7 Abundance (zet2ret_s16 - Sun)
95- 99 F5.3 [Sun] stot7 Total error (zet2ret_s16 - Sun)
101-106 F6.3 [Sun] [X/H]8 Abundance (zet2ret_c - Sun)
108-112 F5.3 [Sun] stot8 Total error (zet2ret_c - Sun)
114-119 F6.3 [Sun] [X/H]9 Abundance (zet2ret_b - Sun)
121-125 F5.3 [Sun] stot9 Total error (zet2ret_b - Sun)
127-132 F6.3 [Sun] [X/H]10 Abundance (zet2ret_a - Sun)
134-138 F5.3 [Sun] stot10 Total error (zet2ret_a - Sun)
140-145 F6.3 [Sun] [X/H]11 Abundance (zet2ret_comb - zet1ret_comb)
147-151 F5.3 [Sun] stot11 Total error (zet2ret_comb - zet1ret_comb)
153-158 F6.3 [Sun] [X/H]12 Abundance (zet2ret_s16 - zet1ret_s16)
160-164 F5.3 [Sun] stot12 Total error (zet2ret_s16 - zet1ret_s16)
166-171 F6.3 [Sun] [X/H]13 Abundance (zet1ret_b - zet1ret_a)
173-177 F5.3 [Sun] stot13 Total error (zet1ret_b - zet1ret_a)
179-184 F6.3 [Sun] [X/H]14 Abundance (zet1ret_c - zet1ret_a)
186-190 F5.3 [Sun] stot14 Total error (zet1ret_c - zet1ret_a)
192-197 F6.3 [Sun] [X/H]15 Abundance (zet1ret_c - zet1ret_b)
199-203 F5.3 [Sun] stot15 Total error (zet1ret_c - zet1ret_b)
205-210 F6.3 [Sun] [X/H]16 Abundance (zet2ret_b - zet2ret_a)
212-216 F5.3 [Sun] stot16 Total error (zet2ret_b - zet2ret_a)
218-223 F6.3 [Sun] [X/H]17 Abundance (zet2ret_c - zet2ret_a)
225-229 F5.3 [Sun] stot17 Total error (zet2ret_c - zet2ret_a)
231-236 F6.3 [Sun] [X/H]18 Abundance (zet2ret_c - zet2ret_b)
238-242 F5.3 [Sun] stot18 Total error (zet2ret_c - zet2ret_b)
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Byte-by-byte Description of file: s_lines.dat
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Bytes Format Units Label Explanations
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1- 9 F9.4 0.1nm lambda Central wavelength
11- 15 F5.1 --- Elem Element number
17- 21 F5.3 eV EP Excitation potential
23- 28 F6.3 [-] loggf Oscillator strength
30- 33 F4.2 eV DE ? Dissociation energy of molecules
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Acknowledgements:
Vardan Adibekyan, Vardan.Adibekyan(at)astro.up.pt
(End) Vardan Adibekyan [CAUP], Patricia Vannier [CDS] 17-May-2016