Atmospheric Erosion by Giant Impacts onto Terrestrial Planets: A Scaling Law for any Speed, Angle, Mass, and Density. (arXiv:2007.04321v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Kegerreis_J/0/1/0/all/0/1">Jacob A. Kegerreis</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Eke_V/0/1/0/all/0/1">Vincent R. Eke</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Catling_D/0/1/0/all/0/1">David C. Catling</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Massey_R/0/1/0/all/0/1">Richard J. Massey</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Teodoro_L/0/1/0/all/0/1">Luis F. A. Teodoro</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zahnle_K/0/1/0/all/0/1">Kevin J. Zahnle</a>
We present a new scaling law to predict the loss of atmosphere from planetary
collisions for any speed, angle, impactor mass, target mass, and body
compositions, in the regime of giant impacts onto broadly terrestrial planets
with relatively thin atmospheres. To this end, we examine the erosion caused by
a wide range of impacts, using 3D smoothed particle hydrodynamics simulations
with sufficiently high resolution to directly model the fate of low-mass
atmospheres. Different collision scenarios lead to extremely different
behaviours and consequences for the planets. In spite of this complexity, the
fraction of lost atmosphere is fitted well by a power law. Scaling is
independent of the system mass for a constant impactor mass ratio. We find no
evident departure from the trend at the extremes of the parameters explored.
The scaling law can readily be incorporated into models of planet formation.
We present a new scaling law to predict the loss of atmosphere from planetary
collisions for any speed, angle, impactor mass, target mass, and body
compositions, in the regime of giant impacts onto broadly terrestrial planets
with relatively thin atmospheres. To this end, we examine the erosion caused by
a wide range of impacts, using 3D smoothed particle hydrodynamics simulations
with sufficiently high resolution to directly model the fate of low-mass
atmospheres. Different collision scenarios lead to extremely different
behaviours and consequences for the planets. In spite of this complexity, the
fraction of lost atmosphere is fitted well by a power law. Scaling is
independent of the system mass for a constant impactor mass ratio. We find no
evident departure from the trend at the extremes of the parameters explored.
The scaling law can readily be incorporated into models of planet formation.
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