some of the hot jupiters do not match well models based on jupiter & saturn: gas giant planets....
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Some of the Hot Jupiters do not match wellmodels based on Jupiter & Saturn:
Gas Giant Planets. III.
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Our own Solar System: Jupiter & Saturn Eroding Jupiter’s core by convection ? The problem with Saturn’s luminosity
Helium phase separation
Evolution models for extrasolar planets Helium phase separation as a function of planetary mass
Ice Giant Planets: Uranus & Neptune
Outline
Jupiter’s core mass and mass of heavyelements:
Interiors of Giant Planets
Saumon &Guillot (2004)
For MZ -the heavyelements aremixed in theH/He envelope
Saturn’s core mass and mass of heavyelements:
Interiors of Giant Planets
Saumon &Guillot (2004)
Its current luminosity is ~50% greater than predictedby models thatwork for Jupiter:
A Problem with Saturn ?...
Fortney & Hubbard (2004)
Saturn reaches its currentTeff (luminosity) in only2 Gyr !
The only promising idea for resolving the discrepancy - phase separation of neutral He from liquid metallic H (Stevenson & Salpeter 1977):
for a saturation number fraction of the solute (He), phase separation will occur when the temperature drops below T :
x = exp (B - A/kT)where x=0.085 (solar comp., Y=0.27), B=const.
(~0), A~1-2 eV (pressure- dependent const.),
therefore T = 5,000 - 10,000 K
A Problem with Saturn ?…
Phase diagram for H & He:
A Problem with Saturn ?...Fortney & Hubbard (2004)
Model results:
Stevenson (‘75)vs.Pfaffenzelleret al. (‘95) -
different signfor dA/dP !
New models:
A Problem with Saturn ?...Fortney & Hubbard (2004)
Model results:
The modified Pfaffenzelleret al. (‘95) phase diagramresolves the discrepancy.
Good match to observedhelium depletions in theatmospheres of Jupiter (Y=0.234) & Saturn (Y~0.2).
Cooling curves:
Evolution Models of Exo-planets:Fortney & Hubbard (2004)
Models:
All planets have 10 ME
cores & no irradiation.
The models with Heseparation have ~2 xhigher luminosities.
Could the very low-density “puffy” planetsbe heated by phase separation ?
Evolution Models of Exo-planets:
Phase separationof other elements
Ne, O
Could the very low-density “puffy” planetsbe heated by phase separation ?
Evolution Models of Exo-planets:
Phase separationof other elements
Ne, O
Ice Giants: Uranus & Neptune
Conclusions
Sizes of extrasolar planets are already precise beware of biases & systematic errors
Models are based on Jupiter & Saturn Perhaps, Hot & Very Hot Jupiters are more Z
enriched: because of history - excessive migration through disk, or because of orbit - manage to capture more planetesimals ?
Implications for the core-accretion model: it requires at least ~6 ME for Mcore of Jupiter & Saturn invoke Jupiter core erosion (e.g. Guillot 2005), use the He settling for Saturn (Fortney & Hubbard
2003)