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Proceedings Paper

Interstellar transport and local establishment dynamics of spaceborne propagules
Author(s): Jeff Secker; Richard Gomulkiewicz; Mark A. McPeek
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Paper Abstract

We discuss two new factors relevant to the dispersal of established life to hospitable and sterile planets. The first factor concerns the interstellar dispersal of viable microbes within the environment of old, metal-rich, open star clusters. We determine that these clusters present an excellent environment for the transfer of microbial life, since the likelihood of interstellar dispersal is enhanced: the stellar density on the order of 15 stars per pc-3, which decreases the interstellar travel time and raises the probability of collisions between the microbes and planets. As well, the old open clusters remain bound for billions of years, a time scale sufficient for life to arise and be dispersed amongst component starts, after which the open cluster are disrupted, and the component stars are dispersed throughout the Galactic disk. The second factor concerns the probabilistic dynamics of local establishment once an invading propagule is deposited on a planet's surface. We describe a population model relevant to the initial dynamics of invasion for a group of N initial colonists, and discuss processes that affect the long-term persistence of established colonizing groups, including temporal and spatial environmental fluctuations, mutation, and adaptation. This model places a strong constraint on the panspermia hypotheses: not only must microbes survive the hazards associated with transport through interplanetary and interstellar space, but we determined that demographic stochasticity can quickly lead to the extinction of small groups of invading microbes, even if the environment is hospitable for colonization.

Paper Details

Date Published: 6 July 1998
PDF: 11 pages
Proc. SPIE 3441, Instruments, Methods, and Missions for Astrobiology, (6 July 1998); doi: 10.1117/12.319843
Show Author Affiliations
Jeff Secker, Washington State Univ. (Canada)
Richard Gomulkiewicz, Washington State Univ. (United States)
Mark A. McPeek, Darmouth College (United States)

Published in SPIE Proceedings Vol. 3441:
Instruments, Methods, and Missions for Astrobiology
Richard B. Hoover, Editor(s)

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