KITP: making planets stick

Exoplanets Rising continues theoretical rumination, as we contemplate formation, migration, water delivery and evolution

Johansen and Lissauer on oligarchic models before lunch.
Then Mayer on collapse of Too Big Too Fail blobs before Chambers and Raymond return to rocks bashing into each other.
Finish with Mardling looking at the subtleties of tidal evolution.

Ok, Showman and Dobbs-Dixon did the whole giant circulation thing early this morning, but I wasn’t here for that. It is all online if you like that sort of thing.

Good review by Anders on dust bunnies and the irritation dust causes.
Do we need local instabilities do get from dust to rocks without going through the pebble phase?

Planetesimals as rubble piles, or snowballs, depending on how hot you like things.
Whole thing gets to be a bit of a drag, which is important and interesting.

Anders does cool animations…

Hey, I like this – Anders can make protoplanetary cores late in disk lifetime due to enhanced dust/gas ratio – so make planets in low Z systems but too late for migration since a lot of the gas is done. So fewer hot giants in low metallicity systems, but still some wide orbit giants, albeit less massive on average than for high metallicity systems.
(Johansen et al 2009)

This is what I’ve been speculating has to be the case for my favourite planet – good ol’ 1620-26. There are other interesting conceivable ways around the problem, but this one: I like it!

Jack next: what do you need in the core to start rapid gas accretion to make a proper giant.
You have less than 10 Million years, starting NOW!

Jack has more on the Matsya discovery – look about 5 mins into the talk he flashes up the Kepler data!!! Damn, they have THREE of them, that’ll show the CoRoT crowd!

Good review of the issue. Make giant planets faster with higher disk surface densities and lower dust opacities (say what?).

Summary of coarse grained planet formation scenarios at end.
Disk instability scenarios keep hanging in there… stubborn lot those.

We need to make moons – Galilean moons that is.

“Irrational Exuberance in the Field of Planetary Displacement”, hmm, yes.

Nice lunch.

Mayer is on: disk instability formation – especially the newly interesting outer disk prospects, a ~> 50 AU

really need to do cooling properly – get right EoS and at least approx radiative transport
also sensitive to assumed Σ(R,t), of course

argument for why jovian mass is characteristic of disk fragmentation
good summary slide on progress and issues

Chambers: planetesimal growth and terrestrial planets

brings up the role of turbulent eddies and stagnant pools in clumping the dust
does it give right size scales and time scales for the formation of early protoplanetary aggregates and espc. the chondrules?

Hm, this inverts timescales for planetesimal formation – shorter timescales for growth and bigger characteristic lumps at larger distances (Chambers 2010).
Hmm, that is interesting. Might help solve the issues of discrepancies in model formation timescales for giant vs inner terrestrial planets.

Morbidelli et al 2009 say bigger planetesimals initially do better fitting current observed asteroid belt distribution (which is poorly constrained at small sizes)

oligarchies and runaway agglomeration of finite resources
don’t forget fragmentation in collisions

Ramirez et al – 22 solar twins have higher fractional abundance for more refractory metals.
Because Sun has metals tied in planets? Hmm. Maybe.
See Chambers 2010b for some speculation.
Could it be a tracer of terrestrial planet formation?
Why? Signature of failure to form planetesimals? As function of disk mass?
Chambers looks at correlations with Z – signature of more efficient planetesimal formation at higher mean metallicity.

Sean: hydrating planets!
Importance of the snow line – and why don’t we know where it is to a factor of 2 or more?

Dynamical effects on radial transport – giant planets, eccentric giant planets, migrating giant planets. Brilliant!

Role of planet-planet scattering – Malmberg et al, Raymond et al, and Thommes

Nice animation of triple giant planet instability
NB: Spiegel et al 2010 on climate of planets in eccentric orbits

Interesting discussion of dust production in context.
Is cold dust a tracer of terrestrial planet formation in the inner system.

Good question from Bill: what does the dust evolution imply for zodiacal light?
If asteroids are cleared out, then there is less dust, and less opportunity for radial mixing, so less water on the terrestrials.


Rosemary clears out the session:
tidal circularization and circular hot giant planets vs eccentric warm and hot giants.
Eccentricity as a tracer of planetary perturbations, little bits of eccentricity matter.
Resonant coupling matters.

Oh noes. Rosemary has caught on to the role of Kozai in driving giant planets inwards…

How big is your Q, and can we measure it through the Love Number?
Do taxpayers know that we are observing Love Numbers of exotic bodies?

Then the equations come.
It is all Darwin’s fault – no not that Darwin, George Darwin (1879)
130 year old paper that is 140 pages long – took that long for anyone to read it all the way through.

Yes, those are disturbing functions.