A New Desalination Pump Help Define the pH of Ocean Worlds

We study ocean exoplanets, for which the global surface ocean is separated from the rocky interior by a high-pressure ice mantle.

We describe a mechanism that can pump salts out of the ocean, resulting in oceans of very low salinity. Here we focus on the H2O-NaCl system, though we discuss the application of this pump to other salts as well. We find our ocean worlds to be acidic, with a pH in the range of 2-4. We discuss and compare between the conditions found within our studied oceans and the conditions in which polyextremophiles were discovered.

This work focuses on exoplanets in the super-Earth mass range (2 M_Earth), with water composing at least a few percent of their mass. Although, the principal of the desalination pump may extend beyond this mass range.

Amit Levi, Dimitar Sasselov
(Submitted on 23 Mar 2018)

Comments: 61 pages, 18 figures, accepted for publication in ApJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1803.08937 [astro-ph.EP] (or arXiv:1803.08937v1 [astro-ph.EP] for this version)
Submission history
From: Amit Levi
[v1] Fri, 23 Mar 2018 18:09:35 GMT (1441kb,D)
https://arxiv.org/abs/1803.08937
Astrobiology