Cool Stars 14 - Submitted Abstract # 300
This version created on 05 October 2006

Heaven or hell?  Giants and IMPs


Eric Gaidos, University of Hawaii

Jupiter-mass planets on ~0.1 AU orbits are presumed to have migrated
to their present location by angular momentum exchange with a
primordial gas disk or some other mechanism.  The migrating planet
will also shepherd, scatter, and/or accrete interior planetesimals,
and numerical simulations predict that one or more Earth-mass or
larger planets may form near mean-motion resonances.  Such inner
migrated planets (IMPs) can be detected by transit timing or
space-based photometry, and are a test of planet formation models.
The efficiency of sheperding depends on sheperd mass and migration
rate, and the accretion rate in the planetesimal disk is governed by
competition between surface density enhancement and excitation of
planetesimals.  The composition of IMPs is also a probe of chemistry
and plantesimal formation in the outer disk.  IMPs will enter
synchronous rotation on short timescales and the least massive will
lose their atmospheres.  The dayside of IMPs within 0.1 AU of G stars
have surface temperatures great than the silicate solidus and a magma
ocean will form.  Dissipation of giant planet tides will be an
internal heat source powering Io-like volcanism, producing a Na/S-rich
atmosphere.  Loss of volatiles and silicon will slowly erode the
planet.  IMPs around M stars will have lower, even clement, surface
temperatures but because migration occurs within a few Myr, the
luminosity of the star on the Hyashi track was much larger and
volatiles may have been efficiently removed from the system before
they could be bound in sufficiently large bodies.  

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