J/ApJ/829/14 Behavior of heavy elements in H-He-Z mixtures (Soubiran+, 2016)
The properties of heavy elements in giant planet envelopes.
Soubiran F., Militzer B.
<Astrophys. J., 829, 14-14 (2016)>
=2016ApJ...829...14S 2016ApJ...829...14S (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; Models
Keywords: equation of state; planets and satellites: gaseous planets;
planets and satellites: individual: Jupiter, Saturn, Uranus, Neptune
Abstract:
The core-accretion model for giant planet formation suggests a
two-layer picture for the initial structure of Jovian planets, with
heavy elements in a dense core and a thick H-He envelope. Late
planetesimal accretion and core erosion could potentially enrich the
H-He envelope in heavy elements, which is supported by the threefold
solar metallicity that was measured in Jupiter's atmosphere by the
Galileo entry probe. In order to reproduce the observed gravitational
moments of Jupiter and Saturn, models for their interiors include
heavy elements, Z, in various proportions. However, their effect on
the equation of state of the hydrogen-helium mixtures has not been
investigated beyond the ideal mixing approximation. In this article,
we report results from ab initio simulations of fully interacting
H-He-Z mixtures in order to characterize their equation of state and
to analyze possible consequences for the interior structure and
evolution of giant planets. Considering C, N, O, Si, Fe, MgO, and
SiO2, we show that the behavior of heavy elements in H-He mixtures
may still be represented by an ideal mixture if the effective volumes
and internal energies are chosen appropriately. In the case of oxygen,
we also compute the effect on the entropy. We find the resulting
changes in the temperature-pressure profile to be small. A homogeneous
distribution of 2% oxygen by mass changes the temperature in Jupiter's
interior by only 80K.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 52 971 Pressure and internal energy of H-He-Z mixtures
with 220 H, 18 He and NZ heavy entities
table2.dat 64 35 Pressure and internal energy of H-He-O mixtures
with 220 H, 18 He and NO O atoms
table3.dat 54 1543 Effective properties of heavy elements in
H-He mixtures
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See also:
J/ApJ/806/228 : Ab initio EOS for water-hydrogen mixtures (Soubiran+, 2015)
J/ApJ/774/148 : Ab initio EOS for hydrogen-helium mixtures (Militzer+, 2013)
J/ApJ/750/52 : Jupiter model with improved EOS (Nettelmann+, 2012)
J/PASP/123/412 : Exoplanet Orbit Database (Wright+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- El Heavy element identifier (C, Fe, Mg0, N, O, Si,
SiO2)
6- 10 I5 K T [2000/15000] Temperature
12 I1 --- NZ [2/8] Number of heavy element entities inserted
14- 20 F7.5 --- V [0.8/8.2] Volume per nucleus in units
of Å3/nucleus
22- 29 F8.3 GPa P [8/1679] Pressure
31- 35 F5.3 GPa e_P [0.02/0.7] Uncertainty in P
37- 44 F8.5 --- IntE [-3/5] Internal energy per nucleus in units
of eV/nucleus
46- 52 F7.5 --- e_IntE [0.0006/0.3] Uncertainty in IntE
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 K T [3500/10000] Temperature
7 I1 --- NO [4/8] Number of oxygen atoms inserted
9- 16 F8.5 --- V [1/11] Volume per nucleus in units
of Å3/nucleus
18- 24 F7.3 GPa P [6.6/856] Pressure
26- 30 F5.3 GPa e_P [0.02/0.4] Uncertainty in P
32- 39 F8.5 --- IntE [-2.64/1.875] Internal energy per nucleus in units
of eV/nucleus
41- 47 F7.5 --- e_IntE [0.001/0.004] Uncertainty in IntE
49- 56 F8.5 --- F [-8.71/-1.81] Helmholtz free energy per nucleus
in units of eV/nucleus
58- 64 F7.5 --- e_F [0.0001/0.002] Uncertainty in F
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- El Heavy element identifier (C, Fe, Mg0, N, O, Si,
SiO2)
6- 10 I5 K T [2000/15000] Temperature
12- 15 I4 GPa P [10/1950] Pressure
17- 22 F6.3 0.1nm3 V [-7/54] Effective volume per heavy element entity
in units of Å3
24- 29 F6.3 0.1nm3 e_V [0.002/13] Uncertainty in V
31- 37 F7.3 eV IntE [-21/28] Effective energy per heavy element entity
39- 43 F5.3 eV e_IntE [0.002/7] Uncertainty in IntE
45- 49 F5.2 --- S [8/13]? Effective entropy per heavy element entity
in units of kB the Boltzmann constant;
Only for oxygen
51- 54 F4.2 --- e_S [0.04/0.8]? Uncertainty in S
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 09-Dec-2016