Planet seeding and lithopanspermia through gas-assisted capture of interstellar objects

Evgeni Grishin, Hagai B. Perets, Yael Avni
(Submitted on 25 Apr 2018)

Planet formation begins with collisional-growth of small planetesimals accumulating into larger-ones. Such growth occurs while planetesimals are embedded in a gaseous protoplanetary-disk. However, small-planetesimals experience collisions and gas-drag that lead to their destruction on short-timescales, not allowing, or requiring fine-tuned conditions for the efficient growth of ~meter-size planetesimals. Here we show that small (up-to $0.1-10$ km-size) unbound interstellar-objects passing through a gaseous protoplanetary-disk can be efficiently captured to become embedded in the disk. ‘Seeding’ of such planetesimals then catalyze further planetary-growth into planetary embryos, and potentially alleviate the main-challenges with the meter-size growth-“barrier”. Moreover, planetesimal-capture provides a far-more efficient route for lithopanspermia than previously thought, and $\sim 10^{4}$ interstellar objects such as the recently detected 1I/2017-U1 (‘Oumuamua) could have been captured, and become part of the young Solar System.

Comments:    Comments are welcome
Subjects:    Earth and Planetary Astrophysics (astro-ph.EP)
Cite as:    arXiv:1804.09716 [astro-ph.EP] (or arXiv:1804.09716v1 [astro-ph.EP] for this version)
Submission history
From: Evgeni Grishin
[v1] Wed, 25 Apr 2018 18:00:00 GMT (578kb,D)
https://arxiv.org/abs/1804.09716