Triggering Sublimation-driven Activity of Main Belt Comets

Autor(en)

Nader Haghighipour, Thomas Maindl, Christoph Schäfer, Roland Speith, Rudolf Dvorak

Abstrakt

It has been suggested that the comet-like activity of main belt comets (MBCs) is due to the sublimation of sub-surface water-ice that has been exposed as a result of their surfaces being impacted by meter-sized bodies. We have examined the viability of this scenario by simulating impacts between meter-sized and kilometer-sized objects using a smooth particle hydrodynamics approach. Simulations have been carried out for different values of the impact velocity and impact angle, as well as different target material and water-mass fractions. Results indicate that for the range of impact velocities corresponding to those in the asteroid belt, the depth of an impact crater is slightly larger than 10 m, suggesting that if the activation of MBCs is due to the sublimation of sub-surface water-ice, this ice has to exist no deeper than a few meters from the surface. Results also show that ice exposure occurs in the bottom and on the interior surface of impact craters, as well as on the surface of the target where some of the ejected icy inclusions are re-accreted. While our results demonstrate that the impact scenario is indeed a viable mechanism to expose ice and trigger the activity of MBCs, they also indicate that the activity of the current MBCs is likely due to ice sublimation from multiple impact sites and/or the water contents of these objects (and other asteroids in the outer asteroid belt) is larger than the 5% that is traditionally considered in models of terrestrial planet formation, providing more ice for sublimation. We present the details of our simulations and discuss their results and implications.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

University of Hawaii, Eberhard Karls Universität Tübingen

Journal

The Astrophysical Journal

Band

830

Anzahl der Seiten

11

ISSN

0004-637X

DOI

https://doi.org/10.3847/0004-637X/830/1/22

Publikationsdatum

10-2016

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik

Schlagwörter

ASJC Scopus Sachgebiete

Astronomy and Astrophysics, Space and Planetary Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/a5a4aa77-65ca-4dee-9c1b-5e68e2cdc05f