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Shocked H 2 O ice: Thermal emission measurements and the criteria for phase changes during impact events
Author(s) -
Stewart Sarah T.,
Seifter Achim,
Obst Andrew W.
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl035947
Subject(s) - vaporization , impact crater , materials science , shock (circulatory) , thermodynamics , thermal , hypervelocity , phase (matter) , equation of state , water ice , mechanics , atmospheric sciences , geology , physics , astrobiology , quantum mechanics , medicine
Impact cratering events on icy planetary bodies may produce transient liquid water and vapor. We present the first thermal emission measurements from shocked H 2 O ice and derive peak and post‐shock temperatures. Under shock pressures between 8.2 and 13.6 GPa, initially ∼165 K ice is heated to between 673 and 1055 K. In the time frame of the experiment, the shocked H 2 O releases to the saturation vapor curve and does not achieve full decompression. The temperature results are used to validate the new 5‐Phase H 2 O model equation of state (EOS). The 5‐Phase EOS is used to predict the critical shock pressures required to induce melting and vaporization of ice for a wide range of ambient pressures and temperatures. Impact events with velocities as low as ∼1 km/s will initiate phase changes on icy surfaces. Thus, shock‐induced melting and vaporization of ice is a widespread process in the solar system.