  The Kepler mission has discovered more than 4000 exoplanet candidates. Many
are in systems with tightly packed inner planets. Inside-Out Planet Formation
(IOPF) has been proposed to explain these systems. It involves sequential in
situ planet formation at the local pressure maximum of a retreating dead zone
inner boundary (DZIB). Pebbles accumulate at this pressure trap, which builds
up a ring, and then a planet. The planet is expected to grow until it opens a
gap, which helps to both truncate pebble accretion and induce DZIB retreat that
sets the location of formation of the next planet. This simple scenario may be
modified if the planet migrates significantly from its formation location. Thus
planet-disk interactions play a crucial role in the IOPF scenario. We present
numerical simulations that first assess migration of planets of various masses
that are forming at the DZIB of an active accretion disk, where the effective
viscosity rapidly increases in the radially inward direction. We find that the
disk's torques on the planet tend to trap the planet at a location very close
to the initial pressure maximum where it formed. We then study gap opening by
these planets to assess at what mass a significant gap is created. Finally we
present a simple model for DZIB retreat due to penetration of X-rays from the
star to the disk midplane. Overall, these simulations help to quantify both the
mass scale of first,"Vulcan," planet formation and the orbital separation to
the location of second planet formation.
