J/A+A/664/A112 Jupiter interior hydrogen equation of state (Mazevet+, 2022)
Benchmarking the ab initio hydrogen equation of state for the interior
structure of Jupiter.
Mazevet S., Licari A., Soubiran F.
<Astron. Astrophys. 664, A112 (2022)>
=2022A&A...664A.112M 2022A&A...664A.112M (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Planets ; Models
Keywords: planets and satellites: interiors -
planets and satellites: gaseous planets - equation of state
Abstract:
As Juno is presently measuring Jupiter's gravitational moments to
unprecedented accuracy, models for the interior structure of the
planet are putted to the test. While equations of state based on first
principles or ab initio simulations have been available and used for
the two most abundant elements constituting the envelope, hydrogen and
helium, significant discrepancies remain regarding the predictions of
the inner structure of Jupiter. The differences are severe enough to
clutter the analysis of Juno's data and even cast doubts on the
usefulness of these computationally expensive EOSs for the modeling of
the interior of Jupiter and exoplanets at large.
Using our newly developed equations of state for hydrogen and helium,
we asses the ab initio equations of state currently available and
establish their efficiency at predicting the interior structure of
Jupiter in a two-layers model. We paid particular attention to the
calculation of the total entropy for hydrogen that is required to
calculate the convective H-He envelope but is a derived quantity from
ab initio simulations.
The ab initio equations of state used in this work are based on a
parameterization of the ab initio simulation points using a functional
form of the Helmholtz free energy. It extends on our previous work
recently published. Compared to previous ab initio equations of state
available, this latter approach provides an independent mean of
calculating the entropy that was recently pointed out as deficient in
some ab initio results.
By adjusting our free energy parameterization to reproduce previous ab
initio EOS behavior, we identify the source of the disagreement
previously reported for the interior structure of Jupiter. We further
point to area where care should be taken when building EOS for the
modeling of giant planets. This concerns the interpolation between the
ab initio results and the physical models used to cover the low
density range as well as the interpolation of the ab initio simulation
results at high densities. This sensitivity falls well within the
uncertainties of the ab initio simulations. This suggests that
hydrogen EOS should be carefully benchmarked using a simple planetary
model before being used in the more advanced planetary models needed
to interpret the Juno data.We finally provide an updated version of
our ab initio hydrogen EOS recently published.
Description:
Updated version of the hydrogen equation of state based on ab initio
simulations and published in Chabrier, Mazevet, Soubiran,
2019ApJ...872...51C 2019ApJ...872...51C. This version of the EOS given in a limited
temperature and density range follows more accuratly the ab initio
results at high densities. Arbitrary reference energy for the entropy.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 73 29029 Hydrogen equation of state (EOS) table
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 F7.1 K T [130.0/82024.5] Temperature
9- 23 E15.10 g/cm3 rho [0.0/10.0] Density
25- 39 E15.10 GPa P [0.0/44542.66] Pressure
41- 55 F15.12 eV/atm Ubar [0.0/40.13] Internal Energy
57- 73 E17.10 MJ/kg/K Sbar [-0.01/0.45] Entropy
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Acknowledgements:
Stephane Mazevet, stephane.mazevet(at)oca.eu
References:
Chabrier et al., 2019ApJ...872...51C 2019ApJ...872...51C,
A new equation of state for dense hydrogen-helium mixtures
(End) Patricia Vannier [CDS]: 04-Jul-2022