Planet Formation: Some Theoretical Considerations. Morris Podolak Dept. of Geophysical, Atmospheric and Planetary Sciences Tel Aviv University Exoplanets and Binaries Workshop Tel Aviv University December 2012. Attay Kovetz Ravit Helled Allona Vazan Asia Salner. Nature 1989.
Dept. of Geophysical, Atmospheric and Planetary Sciences
Tel Aviv University
Exoplanets and Binaries Workshop Tel Aviv University December 2012
Latham et al., Nature 339 (1989)
… unless the planet moves.
More realistic physics changes this picture. Including magnetic fields, turbulence, realistic temperature gradients, etc. can lengthen the lifetime against migration, and even reverse its direction.
You build models with all kinds of stuff
You fit all you can see
Then you go talk to Tsevi
And you learn that it’s still not enough!
Pollack et al. (1996)
Alibert et al. (2005)
Based on Hubickyj et al. (2005)
Most of the ice remains as vapor in the envelope.
The molecular weight increase can reduce the critical core mass by ~10%.
Iaroslavitz and Podolak (2006)
The grain size distribution in the envelope is not that of interstellar clouds.
This calculation does not allow grains to break up. Including grain breakup leads to smaller grains and the opacity goes back up. The question is still open.
Movshovitz et al. (2009)
(and by equation of state).
20% all in core
20% all in envelope
Baraffe et al. (2008)
Increased molecular weight in the envelope makes the planet smaller, but the associated opacity increase will reverse this effect and keep the planet inflated.
Vazan et al. ( 2012 unpublished)
a = 4x10-4
Lissauer et al. (2009)
D’Angelo et al. (2010))
Migration gets the planet to the turnover point more quickly.
Higher molecular weight in the envelope makes the planet more compact.
But the corresponding increase in opacity keeps the planet extended.
The supply of gas is limited by the disk properties.
We still need to put all this together into a self-consistent model.
Meyer et al. 2002
Helled et al. (2006)
Helled & Schubert (2009)
Not only is the universe stranger than we imagine, it is stranger than we can imagine. – Sir Arthur Eddington
God is subtle but not malicious. – Albert Einstein
There is a tendency to stop looking for more physics once the model fits the observations.
New observations inspire better theory.
Tsevi and I need to keep talking.