The American Astronomical Society is holding its latest meeting (the 215th!) this week, and the team behind NASA's Kepler probe has used the opportunity to announce the first discoveries for the new probe. The first and easiest planets to spot are the so-called "hot Jupiters," massive planets that orbit close to their host stars. And Kepler has indeed spotted them—five in all—in just the first six weeks of data. The probe is budgeted for over two years' worth of observations, and may be extended beyond that, which should provide some hint of its potential.
The super-Jupiters have (with a stunning lack of creativity) been named Kepler 4b, 5b, 6b, 7b, and 8b. The existence of these five have been confirmed using ground-based observatories, while Keplers 1-3 represent known planets that were used to test the instrument and analysis pipeline .
Kepler spots planets by watching for the decrease in light that occurs as they partially eclipse their host stars. All of the new planets have orbital periods of less than five days, which means Kepler had the chance to spot several of these events during the six weeks of data gathering. The short orbital periods also mean that the planets were very close to their host stars, meaning surface temperatures in excess of 2,000�C.
With more time, Kepler should be able to observe transits by planets that are a bit further from their host stars, meaning cooler surfaces, perhaps extending out into the habitable zone. It's also likely that smaller signals, originating from lighter planets, will become apparent once signals from multiple transits are combined in the analysis pipeline. NASA's Jon Morse felt these discoveries were inevitable, stating, "It's only a matter of time before more Kepler observations lead to smaller planets with longer period orbits, coming closer and closer to the discovery of the first Earth analog."