Protoplanet collisions: Statistical properties of ejecta

Author(s)
Samuele Crespi, I. Dobbs-Dixon, Nikolaos Georgakarakos, Nader Haghighipour, Thomas Maindl, Christoph M. Schäfer, Philip Winter
Abstract

The last phase of the formation of rocky planets is dominated by collisions among Moon- to Mars-sized planetary embryos. Simulations of this phase need to handle the difficulty of including the post-impact material without saturating the numerical integrator. A common approach is to include the collision-generated material by clustering it into few bodies with the same mass and uniformly scattering them around the collision point. However, this approach oversimplifies the properties of the collision material by neglecting features that can play important roles in the final structure and composition of the system. In this study, we present a statistical analysis of the orbital architecture, mass, and size distributions of the material generated through embryo-embryo collisions and show how they can be used to develop a model that can be directly incorporated into the numerical integrations. For instance, results of our analysis indicate that the masses of the fragments follow an exponential distribution with an exponent of -2.21 ± 0.17 over the range of 10-7 to 2 × 10-2 Earth-masses. The distribution of the post-impact velocities show that a large number of fragments are scattered towards the central star. The latter is a new finding that may be quite relevant to the delivery of material from the outer regions of the asteroid belt to the accretion zones of terrestrial planets. Finally, we present an analytical model for the 2D distribution of fragments that can be directly incorporated into numerical integrations.

Organisation(s)
Department of Astrophysics
External organisation(s)
Johannes Kepler Universität Linz, University of Hawaii, Eberhard Karls Universität Tübingen, New York University Abu Dhabi, SDB Science-driven Business Ltd
Journal
Monthly Notices of the Royal Astronomical Society
Volume
508
Pages
6013-6022
No. of pages
10
ISSN
0035-8711
DOI
https://doi.org/10.1093/mnras/stab2951
Publication date
10-2021
Peer reviewed
Yes
Austrian Fields of Science 2012
103003 Astronomy, 103004 Astrophysics
Keywords
ASJC Scopus subject areas
Astronomy and Astrophysics, Space and Planetary Science
Portal url
https://ucrisportal.univie.ac.at/en/publications/0fc00442-0810-4765-9078-75573df13cca