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Can comets deliver prebiotic molecules to rocky exoplanets?

Published version
Peer-reviewed

Repository DOI


Change log

Abstract

jats:pIn this work, we consider the potential of cometary impacts to deliver complex organic molecules and the prebiotic building blocks required for life to rocky exoplanets. Numerical experiments have demonstrated that for these molecules to survive, impacts at very low velocities are required. This work shows that for comets scattered from beyond the snow-line into the habitable zone, the minimum impact velocity is always lower for planets orbiting Solar-type stars than M-dwarfs. Using both an analytical model and numerical N-body simulations, we show that the lowest velocity impacts occur onto planets in tightly packed planetary systems around high-mass (i.e. Solar-mass) stars, enabling the intact delivery of complex organic molecules. Impacts onto planets around low-mass stars are found to be very sensitive to the planetary architecture, with the survival of complex prebiotic molecules potentially impossible in loosely packed systems. Rocky planets around M-dwarfs also suffer significantly more high velocity impacts, potentially posing unique challenges for life on these planets. In the scenario that cometary delivery is important for the origins of life, this study predicts the presence of biosignatures will be correlated with (i) decreasing planetary mass (i.e. escape velocity), (ii) increasing stellar-mass and (iii) decreasing planetary separation (i.e. exoplanets in tightly-packed systems).</jats:p>

Description

Peer reviewed: True


Publication status: Published


Funder: Science and Technology Facilities Council (STFC) PhD Studentship

Keywords

5109 Space Sciences, 5101 Astronomical Sciences, 51 Physical Sciences

Journal Title

Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences

Conference Name

Journal ISSN

1364-5021
1471-2946

Volume Title

479

Publisher

The Royal Society
Sponsorship
STFC (ST/W000997/1)
Royal Society (URF\R1\211421)