Transiting Gas Giant a ‘Rosetta Stone’

Claire Moutou, one of an international team of astronomers behind the discovery of the planet CoRoT-9b, says the distant world will become a ‘Rosetta stone in exoplanet research.’ And perhaps it will, for this is a transiting gas giant, but not a ‘hot Jupiter.’ In an orbit not dissimilar to that of Mercury, CoRoT-9b transits its star every 95 days, each transit lasting about eight hours. We’ve identified approximately 70 planets by transit methods, but this one is ten times farther from its host star than most gas giants previously discovered by this technique.
We may be jumping the gun a bit to call the climate here ‘temperate,’ as this European Southern Observatory news release does, because temperatures here will depend on layers of highly reflective clouds that may or may not exist on CoRoT-9b. ESO cites temperatures between 160 degrees and minus twenty degrees Celsius beneath those assumed clouds, but we should be able to learn much more because of the lengthy transit periods. Didier Queloz, a co-author of the Nature paper announcing the find, sees it this way:
“Our analysis has provided more information on CoRoT-9B than for other exoplanets of the same type. It may open up ...