J/A+A/681/A57 Frequencies of solar global acoustic modes (Buldgen+, 2024)
Helioseismic determination of the solar metal mass fraction.
Buldgen G., Noels A., Baturin V.A., Oreshina A.V., Ayukov S.V.,
Scuflaire R., Amarsi A.M., Grevesse N.
<Astron. Astrophys. 681, A57 (2024)>
=2024A&A...681A..57B 2024A&A...681A..57B (SIMBAD/NED BibCode)
ADC_Keywords: Sun ; Asteroseismology ; Models
Keywords: Sun: helioseismology - Sun: oscillations -
Sun: fundamental parameters - Sun: abundances
Abstract:
The metal mass fraction of the Sun Z is a key constraint in solar
modelling, but its value is still under debate. The standard solar
chemical composition of the late 2000s have the ratio of metals to
hydrogen Z/X=0.0181, with a small increase to 0.0187 in 2021, as
inferred from 3D non-LTE spectroscopy. However, more recent work on a
horizontally and temporally averaged <3D> model claim Z/X=0.0225,
consistent with the high values of twenty-five years ago based on 1D
LTE spectroscopy.
We aim to determine a precise and robust value of the solar metal mass
fraction from helioseismic inversions, thus providing independent
constraints from spectroscopic methods.
We devise a detailed seismic reconstruction technique of the solar
envelope, combining multiple inversions and equations of state to
accurately and precisely determine the metal mass fraction value.
Results. We show that a low value of the solar metal mass fraction
corresponding to Z/X=0.0187 is favoured by helioseismic constraints
and that a higher metal mass fraction corresponding to Z/X=0.0225
are strongly rejected by helioseismic data.
We conclude that direct measurement of the metal mass fraction in the
solar envelope favours a low metallicity, in line with the 3D non-LTE
spectroscopic determination of 2021. A high metal mass fraction as
measured using a <3D> model in 2022 is disfavoured by helioseismology
for all modern equations of state used to model the solar convective
envelope.
Description:
Dataset 1 taken as the "optimal dataset" of Basu et al.
(2009ApJ...699.1403B 2009ApJ...699.1403B), which is a combination of BiSON and MDI data.
Total number of frequencies: 2186
Dataset 2 taken from Davies et al. (2014MNRAS.439.2025D 2014MNRAS.439.2025D) and Larson &
Schou (2015SoPh..290.3221L 2015SoPh..290.3221L).
Total number of frequencies: 2156
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
dataset1.dat 25 2186 Frequencies of solar global acoustic modes (Set 1)
dataset2.dat 50 2156 Frequencies of solar global acoustic modes (Set 2)
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Byte-by-byte Description of file: dataset1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 deg l [0/250] Spherical degree of the oscillation mode
5- 6 I2 --- n Radial order of the oscillation mode
8- 16 F9.4 uHz Freq Frequency of global solar acoustic
oscillation mode
18- 25 F8.6 uHz e_Freq One sigma uncertainty of the frequency
of the oscillation mode
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Byte-by-byte Description of file: dataset2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 deg l [0/250] Spherical degree of the oscillation mode
5- 6 I2 --- n Radial order of the oscillation mode
8- 26 F19.14 uHz Freq Frequency of global solar acoustic
oscillation mode
28- 50 E23.17 uHz e_Freq One sigma uncertainty of the frequency
of the oscillation mode
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Acknowledgements:
Gael Buldgen, Gael.Buldgen(at)unige.ch
(End) Patricia Vannier [CDS] 13-Nov-2023