Collision Chains among the Terrestrial Planets. II. An Asymmetry between Earth and Venus

Emsenhuber, Alexandre; Asphaug, Erik; Cambioni, Saverio; Gabriel, Travis S. J.; Schwartz, Stephen R. (2021). Collision Chains among the Terrestrial Planets. II. An Asymmetry between Earth and Venus. The planetary science journal, 2(5), p. 199. IOP Publishing 10.3847/PSJ/ac19b1

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During the late stage of terrestrial planet formation, hit-and-run collisions are about as common as accretionary mergers, for expected velocities and angles of giant impacts. Average hit-and-runs leave two major remnants plus debris: the target and impactor, somewhat modified through erosion, escaping at lower relative velocity. Here we continue our study of the dynamical effects of such collisions. We compare the dynamical fates of intact runners that start from hit-and-runs with proto-Venus at 0.7 au and proto-Earth at 1.0 au. We follow the orbital evolutions of the runners, including the other terrestrial planets, Jupiter, and Saturn, in an N-body code. We find that the accretion of these runners can take ≳10 Myr (depending on the egress velocity of the first collision) and can involve successive collisions with the original target planet or with other planets. We treat successive collisions that the runner experiences using surrogate models from machine learning, as in previous work, and evolve subsequent hit-and-runs in a similar fashion. We identify asymmetries in the capture, loss, and interchange of runners in the growth of Venus and Earth. Hit-and-run is a more probable outcome at proto-Venus, being smaller and faster orbiting than proto-Earth. But Venus acts as a sink, eventually accreting most of its runners, assuming typical events, whereas proto-Earth loses about half, many of those continuing to Venus. This leads to a disparity in the style of late-stage accretion that could have led to significant differences in geology, composition, and satellite formation at Earth and Venus.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute
08 Faculty of Science > Physics Institute > NCCR PlanetS
08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences

UniBE Contributor:

Emsenhuber, Alexandre

Subjects:

500 Science
500 Science > 520 Astronomy
500 Science > 530 Physics
600 Technology > 620 Engineering

ISSN:

2632-3338

Publisher:

IOP Publishing

Language:

English

Submitter:

Janine Jungo

Date Deposited:

24 Mar 2022 13:24

Last Modified:

05 Dec 2022 16:12

Publisher DOI:

10.3847/PSJ/ac19b1

BORIS DOI:

10.48350/166489

URI:

https://boris.unibe.ch/id/eprint/166489

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