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Thermo‐mechanical adjustment after impacts during planetary growth
Author(s) -
Monteux Julien,
Coltice Nicolas,
Dubuffet Fabien,
Ricard Yanick
Publication year - 2007
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 - 10.1029/2007gl031635
Subject(s) - advection , planet , mars exploration program , thermal , accretion (finance) , mechanics , isothermal process , materials science , rotational symmetry , viscosity , diffusion , geology , physics , astrobiology , astrophysics , thermodynamics , composite material
The thermal evolution of planets during their growth is strongly influenced by impact heating. The temperature increase after a collision is mostly located next to the shock. For Moon to Mars size planets where impact melting is limited, the long term thermo‐mechanical readjustment is driven by spreading and cooling of the heated zone. To determine the time and length scales of the adjustment, we developed a numerical model in axisymmetric cylindrical geometry with variable viscosity. We show that if the impactor is larger than a critical size, the spherical heated zone isothermally flattens until its thickness reaches a value for which motionless thermal diffusion becomes more effective. The thickness at the end of advection depends only on the physical properties of the impacted body. The obtained timescales for the adjustment are comparable to the duration of planetary accretion and depend mostly on the physical properties of the impacted body.