But staring at 150,000 stars for four years turned up thousands of other potential planets, including four candidate planets with orbits 20 times closer than Mercury circles the sun.
Surface temperatures on these planets would soar past 3,000 degrees Fahrenheit -- hot enough to melt rock.
One suspected planet, referred to as KOI-1843, circles its host star in 4.2 hours -- an orbit that brings it 40 times closer to its star than Mercury orbits the sun -- with a surface temperatures of about 4,200 degrees Fahrenheit.
Conditions on these planets would be extreme. Surfaces on their day-sides are likely molten rock, setting up the bizarre prospect of rocky vapor atmospheres that transform into "rock snow" falling on their relatively cooler night-sides.
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"That could be very interesting," Jackson told reporters during a webcast press conference at the American Astronomical Society meeting in Denver this week.
"These molten rock lakes could shed a rocky vapor atmosphere that could go screaming around to the night side of the planet and then be deposited as sort of a rock snow as the rock vapor cools," Jackson said.