Implicações da água de cometas

Implications of cometary water: Deep Impact, Stardust and Hayabusa

Robert B. Sheldon and Richard B. Hoover

NASA/MSFC/NSSTC, 320 Sparkman Dr, Huntsville, AL, USA

ABSTRACT

Three recent in situ spacecraft missions have explored comets or asteroids, producing data in conflict with the standard comet paradigm, the Whipple Dirty Snowball Model (DSM). We have developed an alternative Wet Comet Model (WCM) which proposes that comets undergo an irreversible phase change to a wet comet when they enter within Mars orbit. The WCM may explain some of the observational discrepancies seen by Deep
Impact, Stardust and Hayabusa. In particular, it accurately predicted Deep Impact observation of organics, biominerals, and meltwater temperatures. Predictions concerning Stardust's returned cometary dust particles have yet to be falsied, but if comets are largely composed of the silicates seen by Stardust, there may be a cometary explanation for Itokawa's low density rubble-pile observed by Hayabusa.

Keywords: Comet, liquid water, astrobiology, orbital dynamics, geysers, Deep Impact, Stardust, Hayabusa

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