Damage due to ultraviolet and ionizing radiation during the ejection of shielded micro-organisms from the vicinity of 1M
⊙ main sequence and red giant stars |
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| Authors: | Jeff Secker James Lepock Paul Wesson |
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| Institution: | (1) Department of Physics and Astronomy, McMaster University, L8S 4M1 Hamilton, Ontario, Canada;(2) Department of Physics, University of Waterloo, N2L 3G1 Waterloo, Ontario, Canada |
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| Abstract: | We present the astrophysical conditions necessary for the ejection of shielded microorganisms from a solar system and the biological conditions involving ultraviolet and ionizing radiations to which they are subjected in space. The radiation dose for both UV and ionizing radiation from the host star, the destination star and interstellar space is calculated for three different micro-organisms. The time of transport and the survival of the micro-organisms are strongly dependent on the composition and thickness of any mantle encasing the micro-organism and on the mass/luminosity ratio of the two stars. The maximum size of grains that can be ejected from the vicinity of one solar mass main sequence and red giant stars ranges from 0.65-0.35µm and 2.1-1.2µm respectively, for a reasonable range of densities. We conclude that unshielded known micro-organisms are immediately killed by ultraviolet radiation, and that an ice mantle does not provide sufficient shielding for either type of star. However, micro-organisms shielded by a carbonaceous thin-film mantle can be ejected from the vicinity of a one solar-mass red-giant star, and such micro-organisms have a high probability of surviving damage from the ultraviolet and ionizing radiations to which they are exposed. |
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