The smaller of the two planets, dubbed Kepler-20 e, is about the size of Venus, with a radius 0.87 times that of Earth. It orbits its star every 6 Earth days and sits at a temperature of 1,040 Kelvin — hot enough to vaporize any atmosphere and leave a solid hunk of silica- and iron-rich rock.
Kepler-20 f, the larger planet with a radius 1.03 times that of Earth, has a 20-day orbit. As a result, it is a bit less scorching, at 705 Kelvin. At that temperature, says Fressin, hydrogen and helium wouldn’t survive in the atmosphere, but a shroud of water vapour might.
Then there is this planet Alpha Centauri Bb
This planet orbits very close to its star, like Kepler-20 e, in fact its close enough that its surface is most likely molten. But its only 4 light years away and generally where there is one planet there are likely others. This planet was not discovered by the Kepler observatory and there is some discussion as to the data set used to derive its existence…but it seems likely that its there and it’s certainly cool….