J/A+A/699/A46 Solar analogs abundances (Martos+, 2025)
Signatures of planets and Galactic subpopulations in solar analogs.
Precise chemical abundances obtained with Neural Networks.
Martos G., Melendez J., Spina L., Lucatello S.
<Astron. Astrophys. 699, A46 (2025)>
=2025A&A...699A..46M 2025A&A...699A..46M (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Stars, G-type ; Abundances
Keywords: planets and satellites: detection - stars: abundances -
stars: fundamental parameters - stars: solar-type -
Galaxy: abundances - Galaxy: disk
Abstract:
The aim of this work was to obtain precise atmospheric parameters
and chemical abundances automatically for solar twins, in order to
find signatures of exoplanets, assess how peculiar is the Sun
compared to these stars and analyze possible fine structures in the
Galactic thin disk.
We developed a Neural Network algorithm using python to derive
atmospheric parameters and chemical abundances for a sample of 99
solar twins previously studied in the literature directly from
normalized high-quality spectra from HARPS, with resolving power
R∼115000 and signal-to-noise ratio S/N>400. Results. We obtained
precise atmospheric parameters and abundance ratios [X/Fe] of 20
chemical elements (Li, C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn,
Co, Ni, Cu, Zn, Y and Ba). The results obtained are in line with the
literature, with average differences and standard deviations of
(2±27)K for Teff , (0.00±0.06)dex for logg, (0.00±0.02)dex for
[Fe/H], (-0.01±0.05)km/s for micro turbulence velocity (vt),
(0.02±0.08)km/s for macro turbulence velocity (vmacro) and
(-0.12±0.26)km/s for projected rotational velocity (vsini).
Regarding the chemical abundances, most of the elements agree with the
literature within 0.01-0.02dex. The abundances were corrected from the
effects of the Galactic Chemical Evolution through a fitting versus
the age of the stars and analyzed with the condensation temperature
(Tcond ) to verify if the stars presented depletion of refractories
compared to volatiles.
We found that the Sun is more depleted in refractory elements compared
to volatiles than 89% of the studied solar twins, with a significance
of 9.5σ when compared to the stars without detected exoplanets.
We also found the possible presence of three subpopulations in the
solar twins, one Cu-rich, one Cu-poor, and the other slightly older
and poor in Na.
Description:
We used neural networks (NNs) to obtain precise atmospheric parameters
and abundance ratios [X/Fe] of 20 elements for a sample of 99 solar
twins and analogs, using high-quality spectra from HARPS. The results
obtained are in line with the literature, with average residuals and
standard deviations of (2.0±27.1)K for Teff, (0.00±0.06)dex for
logg, (0.00±0.02) dex for [Fe/H], (-0.01±0.05)km/s for vt,
(0.02±0.08)km/s for vmacro, and (-0.12±0.26) km/s for vsini.
It was possible to achieve the desired precision of 0.01dex for
approximately half of the elements (Na, Mg, Al, Si, Ca, Ti, Cr, Co,
Ni, and Cu) and about 0.02dex for the rest.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 80 99 Stellar parameters obtained using Neural Networks
tablea2.dat 276 99 Chemical abundances obtained using Neural Networks
tablea3.dat 52 20 Solar abundances obtained using spectra of the
Moon, Venus and Ganymede
coefs.dat 48 20 Coefficients of the linear fit of the chemical
abundances versus age
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Star Name of the star
11 A1 --- n_Star [p] p for planet host
13- 16 I4 K Teff Effective temperature
18- 19 I2 K e_Teff rms uncertainty of the effective temperature
21- 25 F5.3 [cm/s2] logg Surface gravity
27- 31 F5.3 [cm/s2] e_logg rms uncertainty of surface gravity
33- 38 F6.3 --- [Fe/H] Metallicity [Fe/H]
40- 44 F5.3 --- e_[Fe/H] rms uncertainty of metallicity [Fe/H]
46- 50 F5.3 km/s vmic Microturbulence velocity
52- 56 F5.3 km/s e_vmic rms uncertainty of microturbulence velocity
58- 62 F5.3 km/s vmac Macroturbulence velocity
64- 68 F5.3 km/s e_vmac rms uncertainty of macroturbulence velocity
70- 74 F5.3 km/s vsini Rotational velocity
76- 80 F5.3 km/s e_vsini rms uncertainty of rotational velocity
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Star Name of the star
11 A1 --- n_Star [p] p for planet host
13- 18 F6.3 --- [Li/Fe] ? Abundance [Li/Fe]
20- 24 F5.3 --- e_[Li/Fe] ? rms uncertainty on [Li/Fe]
26- 31 F6.3 --- [C/Fe] Abundance [C/Fe]
33- 37 F5.3 --- e_[C/Fe] rms uncertainty on [C/Fe]
39- 44 F6.3 --- [O/Fe] ? Abundance [O/Fe]
46- 50 F5.3 --- e_[O/Fe] ? rms uncertainty on [O/Fe]
52- 57 F6.3 --- [Na/Fe] Abundance [Na/Fe]
59- 63 F5.3 --- e_[Na/Fe] rms uncertainty on [Na/Fe]
65- 70 F6.3 --- [Mg/Fe] Abundance [Mg/Fe]
72- 76 F5.3 --- e_[Mg/Fe] rms uncertainty on [Mg/Fe]
78- 83 F6.3 --- [Al/Fe] Abundance [Al/Fe]
85- 89 F5.3 --- e_[Al/Fe] rms uncertainty on [Al/Fe]
91- 96 F6.3 --- [Si/Fe] Abundance [Si/Fe]
98-102 F5.3 --- e_[Si/Fe] rms uncertainty on [Si/Fe]
104-109 F6.3 --- [S/Fe] Abundance [S/Fe]
111-115 F5.3 --- e_[S/Fe] rms uncertainty on [S/Fe]
117-122 F6.3 --- [Ca/Fe] Abundance [Ca/Fe]
124-128 F5.3 --- e_[Ca/Fe] rms uncertainty on [Ca/Fe]
130-135 F6.3 --- [Sc/Fe] Abundance [Sc/Fe]
137-141 F5.3 --- e_[Sc/Fe] rms uncertainty on [Sc/Fe]
143-148 F6.3 --- [Ti/Fe] Abundance [Ti/Fe]
150-154 F5.3 --- e_[Ti/Fe] rms uncertainty on [Ti/Fe]
156-161 F6.3 --- [V/Fe] Abundance [V/Fe]
163-167 F5.3 --- e_[V/Fe] rms uncertainty on [V/Fe]
169-175 F7.4 --- [Cr/Fe] Abundance [Cr/Fe]
177-181 F5.3 --- e_[Cr/Fe] rms uncertainty on [Cr/Fe]
183-189 F7.4 --- [Mn/Fe] Abundance [Mn/Fe]
191-195 F5.3 --- e_[Mn/Fe] rms uncertainty on [Mn/Fe]
197-202 F6.3 --- [Co/Fe] Abundance [Co/Fe]
204-208 F5.3 --- e_[Co/Fe] rms uncertainty on [Co/Fe]
210-215 F6.3 --- [Ni/Fe] Abundance [Ni/Fe]
217-221 F5.3 --- e_[Ni/Fe] rms uncertainty on [Ni/Fe]
223-228 F6.3 --- [Cu/Fe] Abundance [Cu/Fe]
230-234 F5.3 --- e_[Cu/Fe] rms uncertainty on [Cu/Fe]
236-241 F6.3 --- [Zn/Fe] Abundance [Zn/Fe]
243-247 F5.3 --- e_[Zn/Fe] rms uncertainty on [Zn/Fe]
249-255 F7.4 --- [Ba/Fe] Abundance [Ba/Fe]
257-261 F5.3 --- e_[Ba/Fe] rms uncertainty on [Ba/Fe]
263-270 F8.5 --- [Y/Fe] ? Abundance [Y/Fe]
272-276 F5.3 --- e_[Y/Fe] ? rms uncertainty on [Y/Fe]
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- El Element ratio
9- 14 F6.3 --- AMoon Solar abundance obtained with Moon spectra
16- 20 F5.3 --- e_AMoon Solar abundance error obtained with
Moon spectra
22- 27 F6.3 --- AVesta Solar abundance obtained with Vesta spectra
29- 33 F5.3 --- e_AVesta Solar abundance error obtained with
Vesta spectra
35- 40 F6.3 --- AGanymede Solar abundance obtained with Ganymede spectra
42- 46 F5.3 --- e_AGanymede Solar abundance error obtained with
Ganymede spectra
48- 52 F5.3 --- Error rms uncertainty adopted for solar abundances
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Byte-by-byte Description of file: coefs.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- El Element ratio
9- 15 F7.4 Gyr-1 A Angular coefficient of the fit (dex/Gyr)
17- 22 F6.4 Gyr-1 e_A rms uncertainty of the angular coefficient of
the fit (dex/Gyr)]
24- 30 F7.4 --- B Linear coefficient of the fit (dex)
32- 37 F6.4 --- e_B rms uncertainty of the linear coefficient of
the fit (dex)
39- 42 F4.1 --- rchi2 Reduced chi-squared
44- 48 F5.3 --- s_resid Standard deviation of the residuals of the fit
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Acknowledgements:
Giulia Martos, gimartos(at)mpia.de
(End) Patricia Vannier [CDS] 30-May-2025