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| Paper: |
Chondrule Formation in Planetesimal Bow Shocks: Heating and Cooling Rates |
| Volume: |
341, Chondrites and the Protoplanetary Disk |
| Page: |
873 |
| Authors: |
Hood, L.L.; Ciesla, F.J.; Weidenschilling, S.J. |
| Abstract: |
If Jupiter formed within a few Myr of CAI formation and if the nebula persisted for a few Myr afterward, then it follows that planetesimal bow shocks would have existed during the chondrule formation epoch. Passage of precursor silicate aggregates through such bow shocks and subsequent accretion onto other planetesimals in nearly circular orbits could represent a plausible mechanism for chondrule formation. Heating and cooling rates for chondrules formed in this manner have recently been estimated using a detailed one-dimensional steady-state shock model that accounts for particlegas momentum and energy transfer. For nominal model parameters (e.g., solids to gas mass ratio of 0.005; wavelength averaged emissivity of 0.9; mass ratio of chondrule sized particles to micron-sized particles of 75%) heating rates in the 1200 to 1600 K temperature range are +103-104 K/hour. Cooling rates at temperatures above the assumed solidus (1400 K) are of the order of −103 K/hr for a planetesimal radius of 1000 km and increase in magnitude with decreasing planetesimal radius. |
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