Protostars and Planets VI, Heidelberg, July 15-20, 2013
Poster 2K084
CHONDRULE FORMATION: NEBULAR GAS CONFINEMENT OF IMPACT SPLASHES
Dullemond, Cornelis Petrus (Heidelberg University, Institute for Theoretical Astrophysics, Albert-Ueberle-Strasse 2, 69120 Heidelberg, Germany)
Johansen, Anders (Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, Sweden)
Abstract:
We show that the impact debris from a high-speed collision between two
planetesimals during the first few million years would sweep up the nebular
gas as a snow plow, leading to deceleration and compression of the debris
into a thin shell. This shell breaks up into dense bullets through the
Rayleigh-Taylor instability. As a result of the compression by the gas,
these bullets will have super-Roche densities and thus will gravitationally
collapse to form new planetesimals. Chondrules that may have formed from
impact melting would thus rapidly be reaccreted into planetesimals. These
dense environments are ideal for forming compound chondrules. The
hydrodynamic interaction with the nebular gas could lead to mixing between
the newly formed chondrules and surviving pre-impact material. Volatiles can
be exchanged between these components in the dense bullets, allowing for
chemical complementarity. We believe that this scenario may have some
advantages over earlier impact scenarios for chondrule formation.
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