Credit: NASA/JPL-Caltech
This artist's concept depicts the planetary system that contains the three smallest exoplanets yet discovered. The dwarf star is one-sixth the size of the sun. The smallest of the three planets, which is about the size of Mars, orbits the farthest from the star and is pictured in the foreground. The next planet to the upper right is 0.78 times the radius of Earth while the planet closest to the star has a radius 0.73 times Earth's.