Atmospheric Erosion by Giant Impacts onto Terrestrial Planets

Abstract

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Atmospheric Erosion by Giant Impacts onto Terrestrial Planets: A Scaling Law for any Speed, Angle, Mass, and Density

“…For the third suite of different-density bodies, we take as a base a fast, grazing scenario (b=0.7, v c =3 v esc ) with the 10 0 M ⊕ target and --10 1, 0.5,0 M ⊕ impactors. These collisions yield middling erosion and tend to align closely with previous scaling laws ( Kegerreis et al 2020). For each of these default planets, we create new versions that are made entirely of iron or entirely of rock (instead of the default 30:70 mass ratio) keeping the same masses and allowing the radii to change, or keeping the same radii and allowing the masses to change, as listed in Table 1.…”

“…For the variable bulk densities in this study, we make the minor change to a fractional interacting mass, f M (b), as detailed in Appendix B, though this modification makes little quantitative are set ignoring the atmosphere and neglecting any tidal distortion before the collision. The initial separation is set such that the time to impact under the same assumptions is 1 hr, using the equations in Appendix A of Kegerreis et al (2020). 6 The WoMa code for producing spherical and spinning planetary profiles and initial conditions is publicly available with documentation and examples at github.com/srbonilla/WoMa, and the python module woma can be installed directly with pip (Ruiz-Bonilla et al 2020).…”

“…In order to run the simulations until the amount of eroded material no longer changes significantly (see Kegerreis et al 2020, their Figure 6), high-speed and/or low-angle scenarios with v c =3, or v c =2 and b=0, 0.3, are run for 5 hr after contact, the others are run conservatively for 14 hr (plus the initial 1 hour before contact in both cases). The three simulations with b=0.9, v c =1 v esc , and an impactor:target mass ratio of 10 −0.25 are exceptions and are stopped (in terms of their analysis) after 8.5 hr, before the nearly intact impactor fragment re-collides with the target.…”

Venus, an Astrobiology Target

“…It is not known whether Venus lost its water gradually over time through warming or through episodic impacts (e.g., Ahrens, 1993;Kegerreis et al, 2020). However, it is important to learn the history of water on Venus because it contextualizes the potential timeline of the origin of life, and the divergent evolution of the two most similar planets in our solar system.…”

TFBN: A Cost Effective High Performance Hierarchical Interconnection Network

“…In addition, these techniques are not enough to solve some computation-intensive problems and grand challenge problems. For example, recently the impact of a planetary collision is revealed by the simulation, and this simulation is carried out by a COSmology MAchine (COSMA) supercomputer to have the simulation result in a reasonable time [2]. Definitely, a rational researcher could not expect a simulation will take a couple of months or even years.…”