Evolution and Structure of Giant Planets Nadine Nettelmann

“Evolution and Structure of Giant Planets" Nadine Nettelmann (U Rostock) • Jupiter standard models Acknowledgement: • Observational constraints • H/He phase diagram • Jupiter & Saturn models with He rain Jonathan Fortney (UCSC), Ronald Redmer (U Rostock) Winfried Lorenzen, Kevin Moore, Chris Mankovich (UCSC), Martin French (U Rostock) N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre

Schematic interior structure of H/He gas planets origin? Z, He, H 2 ~100 K fluid, convective, adiabatic transition region ~1 -10 Mbar origin? plasma, convective, adiabatic B-field? Z, He, H+ ~5 - 50 Mbar, ~5 - 50, 000 K <100 Mbar N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre 2 / 22

Standard Jupiter structure models LM-REOS SCv. Hi Sesame Militzer et al 2008 Nettelmann et al 2012 Saumon & Guillot 2004 Saumon et al 1995 Holst et al 2008, 2011; Becker +2014 Atreya et al. 2003 Lodders 2003 N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre 3 / 22

What may be the origin of a layer boundary? Plasma phase transition in H? Not anymore! The formation process? (Lozovsky, Helled et al 2017) T (K) metallic fluid 250 MEarth nonmetallic fluid solid P (GPa) Becker 2015, Ph. D Thesis Helium rain ? N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre 4 / 22

Observational constraints the standard models cannot explain N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre

1. Saturn‘s high luminosity N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre 6 / 22

2. Saturn‘s dipolar, axisymmetric magnetic field < 1° A thick stable, and/or differentially rotating region can axisymmetrize the B-field. H 2, He stably stratified zone? H+, He rain 1 Mbar, ~ 5000 K H+, He www. lasp. colorado. edu/~bagenal/ magn. field generation? core Stevenson 1980, 1982 Cao, Russell, Christensen et al 2011 Cao, Russell, Wicht et al 2012 MECMATPLA winter school 2017, Montgenèvre N. Nettelmann : giant planets 7 / 22

3. Saturn ring waves Cassini/NASA Fuller (2014) N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre

4 4. Uranus‘ low luminosity ( L~Teff ) Hubbard and Mac. Farlane 1980 Uranus Poster by L. Scheibe today H 2 O phase diagram: e. g. French et al 2009 Teff (K) H 2 O experiments: Knutson et al 2012 CH 4 phase diagram: Gao et al 2010 Nettelmann. Hirai : giant planets CH 4 N. experiments: et al 2009 MECMATPLA winter school 2017, Montgenèvre 8 / 22

5. Jupiter‘s atmospheric He-Ne depletion Guillot (2005), Ann. Rev. EPS Wilson & Militzer 2010, PRL MECMATPLA winter school 2017, Montgenèvre Helium: giant rainplanets ? N. Nettelmann 9 / 22

H-He demixing diagram Tdmx (P, x. He) He depleted layer Z H 2 He mixing demixing He enriched layer rocky core Helium particle fraction x. He Lorenzen, Holst, Redmer (2009, 2011) MECMATPLA winter school 2017, Montgenèvre N. Nettelmann : giant planets 11 / 22

H/He phase diagram T(P) , x. He=solar Morales, Hamel, Caspersen, Schwegler (2013) N. Nettelmann : giant planets Militzer & Hubbard (2016), Ap. J MECMATPLA winter school 2017, Montgenèvre 12 / 22

Atmospheric helium abundance predicted by Lorenzen H/He phase diagram (PBE) Saumon et al 1995 Becker et al 2014 N. Nettelmann : giant planets Nettelmann et al 2015 MECMATPLA winter school 2017, Montgenèvre 13 / 22

Jupiter: inhomogeneous He rain zone Lorenzen H/He phase diagram (PBE, -200 K) 1 2 3 4 10 Jup N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre 14 / 22

adiabatic Saturn: He layer ontop the core 1 He layer grows 2 3 4 10 Fortney & Hubbard 2003 Püstow et al 2016 N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre 15 / 22

Inhomogeneity can suppress convection cool, not so dense, low-P rpar rsur instability Dr stability warm, dense, high-P parcel moves adiabatically: - no loss of heat - loss of particles due to rain MECMATPLA winter school 2017, Montgenèvre N. Nettelmann : giant planets 16 / 22

Inhomogeneity can suppress convection cool, not so dense rpar rsur instability Dr > stability warm, dense non-dimensional derivatives < : = R N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre 17 / 22

He rain in thin, stable zone can explain Jupiter N. Nettelmann : giant planets Nettelmann et al 2015 MECMATPLA winter school 2017, Montgenèvre 18 / 22

He rain & stable zone in Saturn? (prelim. ) 1 2 3 4 10 stable convective R N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre 19 / 22

In addition, Z-gradients may dramatically change the cooling behavior. . . 1 MSat, Z-gradient (Leconte & Chabrier 2013) Teff (K) log L / LSun 1 MJup, Z-gradient (Vazan et al 2015) log time (Gyr) CONCLUSION: the uncertainty in Jupiter & Saturn internal structure is currently exploding! N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre 20 / 22

Summary JUPITER Enormous variety in structure models due to different H/He EOS Assumption of He rain in thin, stable zone is consistent with the observational constraints SATURN WANTED He layer formation difficult to avoid unless demixing temperatures are much lower than predicted Experimental benchmark (P, T) points for H/He phase separation N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre 21 / 22

Announcements HP 4 6. Workshop on High Pressure, Planetary, and Plasma Physics 4 -6 October 2017 Göttingen (Germany) Participating institutions: U Rostock, U & BGI Bayreuth, TU & DLR Berlin, DESY & XFEL Hamburg N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre 22 / 22

Appendix N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre

Current H/He phase diagrams are based on FT-DFT-MD simulations DFT-Molecular Dynamics simulations. ions, electron density Exchange. Correlational Functionals: e. g. ; LDA, GGA, PBE, HSE Entropie? Ice X Courtesy of Martin French VASP Package: G. Kresse and J. Hafner, PRB (1993, 1994) G. Kresse and J. Furthmüller, (1996 a, 1996 b) MECMATPLA winter school 2017, Montgenèvre Perdew, Burke, Ernzerhof (1996) Heyd, Scuseria, Ernzerhof (2003, 2006) N. Nettelmann planets Lee et : algiant (2010)

Comparison to shock experiments on H, D chem. pic. PBE Miguel, Guillot, Fayon (2016), A&A N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre

Hydrogen EOS: Hugoniot curves The different H EOS are stiff / compressible at different pressure levels. Other ab initio EOS (for H/He Y=0. 24): Sesame: chem. picture Militzer et al 2008 Los Alamos database Militzer & Hubbard. 2013 SCv. Hi: chem. picture Saumon et al. (1995), Ap. JS H-REOS: ab initio EOS Holst et al. (2008), PRB Becker et al (2014), Ap. JS Experiments: Knudson & Desjarlais (2009) Boriskov et al. (2005) Knudson et al. (2004), PRB Nellis et al (1983) N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre

Comparison to Sandia Z-machine experiments on deuterium DF 2 HSE PIMD PBE DF 1 NQE vd. WDF 2 NQE Knudson et al (2015), Science PIMD: Morales et al 2013, PRL PBE: Lorenzen et al 2010, Morales et al 2010 vdw-DF 2: Lee et al 2010 MECMATPLA winter school 2017, Montgenèvre N. Nettelmann : giant planets

Inhomogeneous & superadiabatic interior with layered instead of overturning convection? Leconte & Chabrier 2012, A&A An inhomogeneous, superadiabatic jovian planet may be ~50% more enriched in heavy elements. N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre

convection – layered convection – stability Leconte & Chabrier (2012) layered conv. ~10 Mirouh et al 2012, Ap. J Stevenson & Salpeter 1977, Ap. JS French et al 2012, Ap. JS N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre

Modeling giant planets Method observational constraints Three-layer structure: ~two convective, adiabatic, and homogeneous envelopes above ice-rock core Y 1 Z 2 Y 2 P 1 -2 CORE metallicity Chabrier et al 1992, Ap. J Guillot 1999, PSS He fraction Miguel et al 2016, A&A explicitly to be adjusted fitting parameters Mp Rp Mcore Yatm Y Y 2 T 1 bar J 2 Z 2 J 4 Z 1 age & heat flux N. Nettelmann : giant planets Militzer et al 2008, 2013 Nettelmann et al. 2008, 2012, Ap. J MECMATPLA winter school 2017, Montgenèvre

Future work: understanding the physics of H/He phase separation and He sedimentation in a planet Nettelmann 2015, CPP N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre

internal He abundance profile The He abundance in the demixing region increases with LH because of warmer interiors. He rain zone, 10 -10, 000 layers adiabatic outer inner envelope H N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre He 1 Mbar ~2. 5 Mbar

Why do we study Jupiter and Saturn? • solar system and planet formation • infer how atmospheres and planetary magnetic fields work by comparative planetology (habitability) • test theoretical / experimental predictions on warm dense matter ESA‘s Cosmic Vision plan 2015 -2025, Theme 2/4: How does the solar system work? http: //sci. esa. int/cosmic-vision/38656 -cosmic-vision-2015 -2025 -the-solar-system/ Missions current: Cassini @ Saturn, Juno @ Jupiter future: JUICE to Jupiter‘s icy moons suggested: Saturn entry probe N. Nettelmann : giant planets MECMATPLA winter school 2017, Montgenèvre