Exocomets in the Proxima Centauri System and Their Importance for Water Transport

©ESO

Proxima Centauri

The scenario and the efficiency of water transport by icy asteroids and comets are still amongst the most important unresolved questions about the early phases of planetary systems.

The detection of Proxima Centauri b (PCb), which moves in the habitable zone, triggered a debate whether or not this planet can be habitable depending on its formation history and available water content. A better understanding of cometary dynamics in extrasolar systems shall provide information about cometary reservoirs and give an insight into water transport especially to planets in the habitable zone.

In our study we perform numerous N-body simulations with PCb and an outer reservoir of comets. We investigate close encounters and collisions with the planet, which are important for the transport of water.

Observers found hints for a second planet with a period up to 500 days. Our studies show that from the dynamical point of view two planets are stable even for a massive second planet with up to ~ 12 Earth masses. The simulations of a possible second planet yield that this planet can stay in a stable orbit very close to PCb. For the study of exocomets we include an additional planet outside of PCb in our calculations and we also consider the in uence of the binary alpha Centauri.

The studies on the dynamics of exocomets reveal that the outer limit for water transport is between 100 and 200 au. From our simulations we estimate the water mass delivered to the planets to be between 0 and 30 Earth oceans.

Richard Schwarz, Akos Bazso, Nikolaos Georgakarakos, Birgit Loibnegger, David Bancelin, Elke Pilat-Lohinger, Kristina Kislyakova, Rudolf Dvorak, Thomas Maindl, Ian Dobbs-Dixon
(Submitted on 13 Nov 2017)

Comments: 13 pages, 9 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Report number: MN-17-2349-MJ
Cite as: arXiv:1711.04685 [astro-ph.EP] (or arXiv:1711.04685v1 [astro-ph.EP] for this version)
Submission history
From: Richard Schwarz
[v1] Mon, 13 Nov 2017 16:28:33 GMT (1808kb,D)
https://arxiv.org/abs/1711.04685
Astrobiology
Astrochemistry

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