Transfer and loss of water in hit-and-run collisions during late-stage planet formation

Autor(en)

Christoph Burger, Thomas I. Maindl, Christoph M. Schäfer

Abstrakt

Collision events between large, similar-sized bodies shape the final characteristics of (terrestrial) planets. Volatile material like water is particularly prone to collisional loss processes, due to its volatile nature, but also because it is preferentially found in the outer layers of colliding bodies. We studied transfer, loss and processing of water in collisions between planetary embryos in the late stages of planet formation, focusing on the peculiarities of hit-and-run collisions. This additional outcome regime emerges in rather grazing encounters between roughly similar-sized bodies and is characterized by two large post-collision objects, originating mainly from the two pre-collision bodies respectively. Besides the common figure of overall water loss, transfer between the two colliding bodies as well as their individual losses have to be considered in hit-and-run encounters. For disentangling these effects we ran a suite of multi-material Smooth Particle Hydrodynamics (SPH) simulations including self-gravity, with varying impact velocity, impact angle and projectile-to-target mass ratio over the full range of reasonable values. We find overall water losses of up to 75% in the most energetic impacts, and much greater effects for the smaller body, which is often stripped of a large fraction of its volatiles while the larger body remains relatively unaltered. Therefore the cumulative effect of a sequence of such collisions can be expected to greatly reduce water contents of growing planets. To additionally study the amount of water vapor production in connection to potential further losses of water vapor atmosphere, we also varied the total colliding mass. Results indicate that these additional losses are particularly important in collisions of Mars-sized embryos, where vapor production is already significant, but their gravity to prevent atmospheric losses is still weak.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

Eberhard Karls Universität Tübingen

Band

345

Publikationsdatum

10-2019

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik

Schlagwörter

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/7b72f474-a116-4191-a12b-2fa20708651b