The Survival Rate of Ejected Terrestrial Planets with Moons - AstrophysicsReport as inadecuate

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Abstract: During planet formation, a gas giant will interact with smaller protoplanetsthat stray within its sphere of gravitational influence. We investigate theoutcome of interactions between gas giants and terrestrial-sized protoplanetswith lunar-sized companions. An interaction between a giant planet and aprotoplanet binary may have one of several consequences, including the deliveryof volatiles to the inner system, the capture of retrograde moons by the giantplanet, and the ejection of one or both of the protoplanets. We show that aninteresting fraction of terrestrial-sized planets with lunar sized companionswill likely be ejected into interstellar space with the companion bound to theplanet. The companion provides an additional source of heating for the planetfrom tidal dissipation of orbital and spin angular momentum. This heat fluxtypically is larger than the current radiogenic heating of the Earth for up tothe first few hundred million years of evolution. In combination with anatmosphere of sufficient thickness and composition, the heating can provide theconditions necesary for liquid water to persist on the surface of theterrestrial mass planet, making it a potential site for life. We also determinethe possibility for directly detecting such systems through all-sky infraredsurveys or microlensing surveys. Microlensing surveys in particular willdirectly measure the frequency of this phenomenon.

Author: J. H. Debes, S. Sigurdsson


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