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A new equation of state for dense hydrogen-helium mixtures
- Source :
- The Astrophysical Journal, The Astrophysical Journal, 2019, 872 (1), ⟨10.3847/1538-4357/aaf99f⟩, The Astrophysical Journal, American Astronomical Society, 2019, 872 (1), ⟨10.3847/1538-4357/aaf99f⟩
- Publication Year :
- 2019
-
Abstract
- We present a new equation of state (EOS) for dense hydrogen/helium mixtures which covers a range of densities from $10^{-8}$ to $10^6$ g.cm$^{-3}$, pressures from $10^{-9}$ to $10^{13}$ GPa and temperatures from $10^{2}$ to $10^{8}$ K. The calculations combine the EOS of Saumon, Chabrier & vanHorn (1995) in the low density, low temperature molecular/atomic domain, the EOS of Chabrier & Potekhin (1998) in the high-density, high-temperature fully ionized domain, the limits of which differ for H and He, and ab initio quantum molecular dynamics (QMD) calculations in the intermediate density and temperature regime, characteristic of pressure dissociation and ionization. The EOS for the H/He mixture is based on the so-called additive volume law and thus does not take into account the interactions between the two species. A major improvement of the present calculations over existing ones is that we calculate the entropy over the entire density-temperature domain, a necessary quantity for stellar or planetary evolution calculations. The EOS results are compared with existing experimental data, namely Hugoniot shock experiments for pure H and He, and with first principle numerical simulations for both the single elements and the mixture. This new EOS covers a wide range of physical and astrophysical conditions, from jovian planets to solar-type stars, and recovers the existing relativistic EOS at very high densities, in the domains of white dwarfs and neutron stars.<br />To appear in Astrophysical Journal. Figures in the published version will be larger
- Subjects :
- Equation of state
dense matter
010504 meteorology & atmospheric sciences
Hydrogen
Ab initio
FOS: Physical sciences
chemistry.chemical_element
01 natural sciences
7. Clean energy
Ionization
0103 physical sciences
stars: low mass
010303 astronomy & astrophysics
Solar and Stellar Astrophysics (astro-ph.SR)
Helium
equation of state
0105 earth and related environmental sciences
white dwarfs
Physics
White dwarf
Astronomy and Astrophysics
planets and satellites: general
plasmas
Neutron star
chemistry
Astrophysics - Solar and Stellar Astrophysics
13. Climate action
Space and Planetary Science
[SDU]Sciences of the Universe [physics]
First principle
Atomic physics
brown dwarfs
Subjects
Details
- Language :
- English
- ISSN :
- 0004637X and 15384357
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal, The Astrophysical Journal, 2019, 872 (1), ⟨10.3847/1538-4357/aaf99f⟩, The Astrophysical Journal, American Astronomical Society, 2019, 872 (1), ⟨10.3847/1538-4357/aaf99f⟩
- Accession number :
- edsair.doi.dedup.....62b7a632fb4850dd28970aae82e51eda